feat(ci): add goreleaser config and release workflow

detect package failed to compile on non-Linux/FreeBSD/OpenBSD because
candidates() and allManagers() had no fallback. Added detect_other.go
with empty implementations.

.github/workflows/release.yml

@@ -0,0 +1,30 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+permissions:
+  contents: write
+
+jobs:
+  goreleaser:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - uses: goreleaser/goreleaser-action@v6
+        with:
+          distribution: goreleaser-pro
+          version: "~> v2"
+          args: release --clean
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GORELEASER_KEY: ${{ secrets.GORELEASER_KEY }}

.goreleaser.yaml

@@ -0,0 +1,97 @@
+# yaml-language-server: $schema=https://goreleaser.com/static/schema.json
+# vim: set ts=2 sw=2 tw=0 fo=cnqoj
+
+version: 2
+
+before:
+  hooks:
+    - go mod tidy
+
+snapshot:
+  name_template: "{{ incpatch .Version }}-next"
+
+builds:
+  - main: ./cmd/snack/
+    id: snack
+    binary: snack
+    goos:
+      - linux
+      - darwin
+      - freebsd
+      - openbsd
+    goarch:
+      - amd64
+      - arm64
+      - arm
+    ldflags:
+      - -X main.version={{.Version}}
+
+universal_binaries:
+  - id: snack-universal
+    ids:
+      - snack
+    name_template: "snack-{{.Version}}-darwin-universal"
+    replace: true
+
+archives:
+  - formats: tar.gz
+    allow_different_binary_count: true
+    ids:
+      - snack
+      - snack-universal
+    name_template: "snack-{{.Version}}-{{.Os}}-{{.Arch}}"
+
+nfpms:
+  - id: snack
+    package_name: snack
+    builds: [snack]
+    formats: [apk, deb, rpm]
+    bindir: /usr/bin
+    description: "A unified CLI for system package managers"
+    maintainer: Tai Groot <tai@taigrr.com>
+    license: 0BSD
+    homepage: https://github.com/gogrlx/snack
+    vendor: Adatomic, Inc.
+
+release:
+  github:
+    owner: gogrlx
+    name: snack
+  ids:
+    - snack
+    - snack-universal
+  draft: true
+  prerelease: auto
+
+changelog:
+  use: github
+  sort: asc
+  abbrev: -1
+  filters:
+    exclude:
+      - "^docs:"
+      - "^test:"
+      - "^ci:"
+      - "^chore:"
+      - "^style:"
+  groups:
+    - title: "Breaking Changes"
+      regexp: "^.*!:+.*$"
+      order: 0
+    - title: "Features"
+      regexp: "^.*feat[(\\w)]*:+.*$"
+      order: 1
+    - title: "Bug Fixes"
+      regexp: "^.*fix[(\\w)]*:+.*$"
+      order: 2
+    - title: "Performance"
+      regexp: "^.*perf[(\\w)]*:+.*$"
+      order: 3
+    - title: "Refactor"
+      regexp: "^.*refactor[(\\w)]*:+.*$"
+      order: 4
+    - title: "Build"
+      regexp: "^.*build[(\\w)]*:+.*$"
+      order: 5
+    - title: Others
+      order: 999

README.md

@@ -11,20 +11,22 @@ Part of the [grlx](https://github.com/gogrlx/grlx) ecosystem.
 
 ## Supported Package Managers
 
-| Package | Manager | Platform | Status |
+| Package | Manager | Platform | Extras |
 |---------|---------|----------|--------|
-| `pacman` | pacman | Arch Linux | 🚧 |
-| `aur` | AUR (makepkg) | Arch Linux | 🚧 |
-| `apk` | apk-tools | Alpine Linux | 🚧 |
-| `apt` | APT (apt-get/apt-cache) | Debian/Ubuntu | 🚧 |
-| `dpkg` | dpkg | Debian/Ubuntu | 🚧 |
-| `dnf` | DNF | Fedora/RHEL | 🚧 |
-| `rpm` | RPM | Fedora/RHEL | 🚧 |
-| `flatpak` | Flatpak | Cross-distro | 🚧 |
-| `snap` | snapd | Cross-distro | 🚧 |
-| `pkg` | pkg(8) | FreeBSD | 🚧 |
-| `ports` | ports/packages | OpenBSD | 🚧 |
-| `detect` | Auto-detection | All | 🚧 |
+| `apt` | APT (apt-get/apt-cache) | Debian/Ubuntu | DryRun, FileOwner, Holder, KeyManager, NameNormalizer, RepoManager |
+| `dpkg` | dpkg | Debian/Ubuntu | DryRun, FileOwner, NameNormalizer |
+| `dnf` | DNF 4/5 | Fedora/RHEL | DryRun, FileOwner, Grouper, Holder, KeyManager, NameNormalizer, RepoManager |
+| `rpm` | RPM | Fedora/RHEL | FileOwner, NameNormalizer |
+| `pacman` | pacman | Arch Linux | DryRun, FileOwner, Grouper |
+| `aur` | AUR (makepkg) | Arch Linux | — |
+| `apk` | apk-tools | Alpine Linux | DryRun, FileOwner |
+| `flatpak` | Flatpak | Cross-distro | RepoManager |
+| `snap` | snapd | Cross-distro | — |
+| `pkg` | pkg(8) | FreeBSD | FileOwner |
+| `ports` | ports/packages | OpenBSD | FileOwner |
+| `detect` | Auto-detection | All | — |
+
+All providers implement `Manager`, `VersionQuerier`, `Cleaner`, and `PackageUpgrader`. The **Extras** column lists additional capabilities beyond that baseline.
 
 ## Install
 
@@ -50,11 +52,12 @@ func main() {
     ctx := context.Background()
     mgr := apt.New()
 
-    // Install a package
-    err := mgr.Install(ctx, []string{"nginx"}, snack.WithSudo(), snack.WithAssumeYes())
+    // Install packages
+    result, err := mgr.Install(ctx, snack.Targets("nginx", "curl"), snack.WithSudo(), snack.WithAssumeYes())
     if err != nil {
         log.Fatal(err)
     }
+    fmt.Printf("Installed: %d, Unchanged: %d\n", len(result.Installed), len(result.Unchanged))
 
     // Check if installed
     installed, err := mgr.IsInstalled(ctx, "nginx")
@@ -62,6 +65,14 @@ func main() {
         log.Fatal(err)
     }
     fmt.Println("nginx installed:", installed)
+
+    // Upgrade specific packages
+    if up, ok := mgr.(snack.PackageUpgrader); ok {
+        _, err := up.UpgradePackages(ctx, snack.Targets("nginx"), snack.WithSudo(), snack.WithAssumeYes())
+        if err != nil {
+            log.Fatal(err)
+        }
+    }
 }
 ```
 
@@ -75,6 +86,11 @@ if err != nil {
     log.Fatal(err)
 }
 fmt.Println("Detected:", mgr.Name())
+
+// All available managers
+for _, m := range detect.All() {
+    fmt.Println(m.Name())
+}
 ```
 
 ## Interfaces
@@ -83,17 +99,21 @@ snack uses a layered interface design. Every provider implements `Manager` (the
 
 ```go
 // Base — every provider
-snack.Manager           // Install, Remove, Purge, Upgrade, Update, List, Search, Info, IsInstalled, Version
+snack.Manager            // Install, Remove, Purge, Upgrade, Update, List, Search, Info, IsInstalled, Version
 
-// Optional capabilities — type-assert to check
-snack.VersionQuerier    // LatestVersion, ListUpgrades, UpgradeAvailable, VersionCmp
-snack.Holder            // Hold, Unhold, ListHeld (version pinning)
-snack.Cleaner           // Autoremove, Clean (orphan/cache cleanup)
-snack.FileOwner         // FileList, Owner (file-to-package queries)
-snack.RepoManager       // ListRepos, AddRepo, RemoveRepo
-snack.KeyManager        // AddKey, RemoveKey, ListKeys (GPG keys)
-snack.Grouper           // GroupList, GroupInfo, GroupInstall
-snack.NameNormalizer    // NormalizeName, ParseArch
+// Core optional — implemented by all providers
+snack.VersionQuerier     // LatestVersion, ListUpgrades, UpgradeAvailable, VersionCmp
+snack.Cleaner            // Autoremove, Clean (orphan/cache cleanup)
+snack.PackageUpgrader    // UpgradePackages (upgrade specific packages)
+
+// Provider-specific — type-assert to check
+snack.Holder             // Hold, Unhold, ListHeld, IsHeld (version pinning)
+snack.FileOwner          // FileList, Owner (file-to-package queries)
+snack.RepoManager        // ListRepos, AddRepo, RemoveRepo
+snack.KeyManager         // AddKey, RemoveKey, ListKeys (GPG keys)
+snack.Grouper            // GroupList, GroupInfo, GroupInstall, GroupIsInstalled
+snack.NameNormalizer     // NormalizeName, ParseArch
+snack.DryRunner          // SupportsDryRun (honors WithDryRun option)
 ```
 
 Check capabilities at runtime:
@@ -103,8 +123,49 @@ caps := snack.GetCapabilities(mgr)
 if caps.Hold {
     mgr.(snack.Holder).Hold(ctx, []string{"nginx"})
 }
+if caps.FileOwnership {
+    owner, _ := mgr.(snack.FileOwner).Owner(ctx, "/usr/bin/curl")
+    fmt.Println("Owned by:", owner)
+}
 ```
 
+## Options
+
+All mutating operations accept functional options:
+
+```go
+snack.WithSudo()           // prepend sudo
+snack.WithAssumeYes()      // auto-confirm prompts
+snack.WithDryRun()         // simulate (if DryRunner)
+snack.WithVerbose()        // verbose output
+snack.WithRefresh()        // refresh index before operation
+snack.WithReinstall()      // reinstall even if current
+snack.WithRoot("/mnt")     // alternate root filesystem
+snack.WithFromRepo("sid")  // install from specific repository
+```
+
+## CLI
+
+A companion CLI is included at `cmd/snack`:
+
+```bash
+snack install nginx curl     # install packages
+snack remove nginx           # remove packages
+snack upgrade                # upgrade all packages
+snack update                 # refresh package index
+snack search redis           # search for packages
+snack info nginx             # show package details
+snack list                   # list installed packages
+snack which /usr/bin/curl    # find owning package
+snack hold nginx             # pin package version
+snack unhold nginx           # unpin package version
+snack clean                  # autoremove + clean cache
+snack detect                 # show detected managers + capabilities
+snack version                # show version
+```
+
+Global flags: `--manager <name>`, `--sudo`, `--yes`, `--dry-run`
+
 ## Design
 
 - **Thin CLI wrappers** — each sub-package wraps a package manager's CLI tools. No FFI, no library bindings.
@@ -115,27 +176,6 @@ if caps.Hold {
 - **Platform-safe** — build tags ensure packages compile everywhere but only run where appropriate.
 - **No root assumption** — use `snack.WithSudo()` when elevated privileges are needed.
 
-## Implementation Priority
-
-1. pacman + AUR (Arch Linux)
-2. apk (Alpine Linux)
-3. apt + dpkg (Debian/Ubuntu)
-4. dnf + rpm (Fedora/RHEL)
-5. flatpak + snap (cross-distro)
-6. pkg + ports (BSD)
-
-## CLI
-
-A companion CLI tool is planned for direct terminal usage:
-
-```bash
-snack install nginx
-snack remove nginx
-snack search redis
-snack list
-snack upgrade
-```
-
 ## License
 
 0BSD — see [LICENSE](LICENSE).

apk/apk_test.go

@@ -17,13 +17,23 @@ func TestSplitNameVersion(t *testing.T) {
 		{"libcurl-doc-8.5.0-r0", "libcurl-doc", "8.5.0-r0"},
 		{"go-1.21.5-r0", "go", "1.21.5-r0"},
 		{"noversion", "noversion", ""},
+		// Edge cases
+		{"", "", ""},
+		{"a-1", "a", "1"},
+		{"my-pkg-name-0.1-r0", "my-pkg-name", "0.1-r0"},
+		{"a-b-c-3.0", "a-b-c", "3.0"},
+		{"single", "single", ""},
+		{"-1.0", "-1.0", ""},  // no digit follows last hyphen at position > 0
+		{"pkg-0", "pkg", "0"},
 	}
 	for _, tt := range tests {
-		name, ver := splitNameVersion(tt.input)
-		if name != tt.name || ver != tt.version {
-			t.Errorf("splitNameVersion(%q) = (%q, %q), want (%q, %q)",
-				tt.input, name, ver, tt.name, tt.version)
-		}
+		t.Run(tt.input, func(t *testing.T) {
+			name, ver := splitNameVersion(tt.input)
+			if name != tt.name || ver != tt.version {
+				t.Errorf("splitNameVersion(%q) = (%q, %q), want (%q, %q)",
+					tt.input, name, ver, tt.name, tt.version)
+			}
+		})
 	}
 }
 
@@ -46,6 +56,111 @@ musl-1.2.4-r2 x86_64 {musl} (MIT) [installed]
 	}
 }
 
+func TestParseListInstalledEdgeCases(t *testing.T) {
+	t.Run("empty input", func(t *testing.T) {
+		pkgs := parseListInstalled("")
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages, got %d", len(pkgs))
+		}
+	})
+
+	t.Run("whitespace only", func(t *testing.T) {
+		pkgs := parseListInstalled("   \n  \n  ")
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages, got %d", len(pkgs))
+		}
+	})
+
+	t.Run("single package", func(t *testing.T) {
+		pkgs := parseListInstalled("busybox-1.36.1-r5 x86_64 {busybox} (GPL-2.0-only) [installed]\n")
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Name != "busybox" || pkgs[0].Version != "1.36.1-r5" {
+			t.Errorf("unexpected package: %+v", pkgs[0])
+		}
+	})
+
+	t.Run("not installed", func(t *testing.T) {
+		pkgs := parseListInstalled("curl-8.5.0-r0 x86_64 {curl} (MIT)\n")
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Installed {
+			t.Error("expected Installed=false")
+		}
+	})
+}
+
+func TestParseListLine(t *testing.T) {
+	tests := []struct {
+		name      string
+		line      string
+		wantName  string
+		wantVer   string
+		wantArch  string
+		installed bool
+	}{
+		{
+			name:      "full line",
+			line:      "curl-8.5.0-r0 x86_64 {curl} (MIT) [installed]",
+			wantName:  "curl",
+			wantVer:   "8.5.0-r0",
+			wantArch:  "x86_64",
+			installed: true,
+		},
+		{
+			name:      "no installed marker",
+			line:      "vim-9.0-r0 x86_64 {vim} (Vim)",
+			wantName:  "vim",
+			wantVer:   "9.0-r0",
+			wantArch:  "x86_64",
+			installed: false,
+		},
+		{
+			name:      "name only",
+			line:      "curl-8.5.0-r0",
+			wantName:  "curl",
+			wantVer:   "8.5.0-r0",
+			wantArch:  "",
+			installed: false,
+		},
+		{
+			name:      "empty line",
+			line:      "",
+			wantName:  "",
+			wantVer:   "",
+			wantArch:  "",
+			installed: false,
+		},
+		{
+			name:      "aarch64 arch",
+			line:      "openssl-3.1.4-r0 aarch64 {openssl} (Apache-2.0) [installed]",
+			wantName:  "openssl",
+			wantVer:   "3.1.4-r0",
+			wantArch:  "aarch64",
+			installed: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkg := parseListLine(tt.line)
+			if pkg.Name != tt.wantName {
+				t.Errorf("Name = %q, want %q", pkg.Name, tt.wantName)
+			}
+			if pkg.Version != tt.wantVer {
+				t.Errorf("Version = %q, want %q", pkg.Version, tt.wantVer)
+			}
+			if pkg.Arch != tt.wantArch {
+				t.Errorf("Arch = %q, want %q", pkg.Arch, tt.wantArch)
+			}
+			if pkg.Installed != tt.installed {
+				t.Errorf("Installed = %v, want %v", pkg.Installed, tt.installed)
+			}
+		})
+	}
+}
+
 func TestParseSearch(t *testing.T) {
 	// verbose output
 	output := `curl-8.5.0-r0 - URL retrieval utility and library
@@ -76,6 +191,51 @@ curl-doc-8.5.0-r0
 	}
 }
 
+func TestParseSearchEdgeCases(t *testing.T) {
+	t.Run("empty input", func(t *testing.T) {
+		pkgs := parseSearch("")
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages, got %d", len(pkgs))
+		}
+	})
+
+	t.Run("single result verbose", func(t *testing.T) {
+		pkgs := parseSearch("nginx-1.24.0-r0 - HTTP and reverse proxy server\n")
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Name != "nginx" {
+			t.Errorf("expected nginx, got %q", pkgs[0].Name)
+		}
+		if pkgs[0].Description != "HTTP and reverse proxy server" {
+			t.Errorf("unexpected description: %q", pkgs[0].Description)
+		}
+	})
+
+	t.Run("single result plain", func(t *testing.T) {
+		pkgs := parseSearch("nginx-1.24.0-r0\n")
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Name != "nginx" || pkgs[0].Version != "1.24.0-r0" {
+			t.Errorf("unexpected package: %+v", pkgs[0])
+		}
+		if pkgs[0].Description != "" {
+			t.Errorf("expected empty description, got %q", pkgs[0].Description)
+		}
+	})
+
+	t.Run("description with hyphens", func(t *testing.T) {
+		pkgs := parseSearch("git-2.43.0-r0 - Distributed version control system - fast\n")
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Description != "Distributed version control system - fast" {
+			t.Errorf("unexpected description: %q", pkgs[0].Description)
+		}
+	})
+}
+
 func TestParseInfo(t *testing.T) {
 	output := `curl-8.5.0-r0 installed size:
 description: URL retrieval utility and library
@@ -94,11 +254,84 @@ webpage: https://curl.se/
 	}
 }
 
+func TestParseInfoEdgeCases(t *testing.T) {
+	t.Run("empty input", func(t *testing.T) {
+		pkg := parseInfo("")
+		if pkg == nil {
+			t.Fatal("expected non-nil (parseInfo always returns a pkg)")
+		}
+	})
+
+	t.Run("no description", func(t *testing.T) {
+		pkg := parseInfo("arch: aarch64\n")
+		if pkg == nil {
+			t.Fatal("expected non-nil")
+		}
+		if pkg.Arch != "aarch64" {
+			t.Errorf("expected aarch64, got %q", pkg.Arch)
+		}
+		if pkg.Description != "" {
+			t.Errorf("expected empty description, got %q", pkg.Description)
+		}
+	})
+
+	t.Run("multiple colons in value", func(t *testing.T) {
+		pkg := parseInfo("description: A tool: does things: really well\n")
+		if pkg == nil {
+			t.Fatal("expected non-nil")
+		}
+		// Note: strings.Cut splits on first colon only
+		if pkg.Description != "A tool: does things: really well" {
+			t.Errorf("unexpected description: %q", pkg.Description)
+		}
+	})
+}
+
 func TestParseInfoNameVersion(t *testing.T) {
-	output := "curl-8.5.0-r0 description:\nsome stuff"
-	name, ver := parseInfoNameVersion(output)
-	if name != "curl" || ver != "8.5.0-r0" {
-		t.Errorf("got (%q, %q), want (curl, 8.5.0-r0)", name, ver)
+	tests := []struct {
+		name    string
+		input   string
+		wantN   string
+		wantV   string
+	}{
+		{
+			name:  "standard",
+			input: "curl-8.5.0-r0 description:\nsome stuff",
+			wantN: "curl",
+			wantV: "8.5.0-r0",
+		},
+		{
+			name:  "single line no version",
+			input: "noversion",
+			wantN: "noversion",
+			wantV: "",
+		},
+		{
+			name:  "multi-hyphen name",
+			input: "lib-ssl-dev-3.0.0-r0 some text",
+			wantN: "lib-ssl-dev",
+			wantV: "3.0.0-r0",
+		},
+		{
+			name:  "empty",
+			input: "",
+			wantN: "",
+			wantV: "",
+		},
+		{
+			name:  "whitespace_only",
+			input: "   ",
+			wantN: "",
+			wantV: "",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			name, ver := parseInfoNameVersion(tt.input)
+			if name != tt.wantN || ver != tt.wantV {
+				t.Errorf("got (%q, %q), want (%q, %q)", name, ver, tt.wantN, tt.wantV)
+			}
+		})
 	}
 }
 
@@ -112,3 +345,151 @@ func TestName(t *testing.T) {
 		t.Errorf("expected apk, got %q", a.Name())
 	}
 }
+
+// Compile-time interface compliance checks
+var (
+	_ snack.VersionQuerier  = (*Apk)(nil)
+	_ snack.Cleaner         = (*Apk)(nil)
+	_ snack.FileOwner       = (*Apk)(nil)
+	_ snack.DryRunner       = (*Apk)(nil)
+	_ snack.PackageUpgrader = (*Apk)(nil)
+)
+
+func TestInterfaceCompliance(t *testing.T) {
+	// Verify at test time as well
+	var m snack.Manager = New()
+	if _, ok := m.(snack.VersionQuerier); !ok {
+		t.Error("Apk should implement VersionQuerier")
+	}
+	if _, ok := m.(snack.Cleaner); !ok {
+		t.Error("Apk should implement Cleaner")
+	}
+	if _, ok := m.(snack.FileOwner); !ok {
+		t.Error("Apk should implement FileOwner")
+	}
+	if _, ok := m.(snack.DryRunner); !ok {
+		t.Error("Apk should implement DryRunner")
+	}
+	if _, ok := m.(snack.PackageUpgrader); !ok {
+		t.Error("Apk should implement PackageUpgrader")
+	}
+}
+
+func TestCapabilities(t *testing.T) {
+	caps := snack.GetCapabilities(New())
+	if !caps.VersionQuery {
+		t.Error("expected VersionQuery=true")
+	}
+	if !caps.Clean {
+		t.Error("expected Clean=true")
+	}
+	if !caps.FileOwnership {
+		t.Error("expected FileOwnership=true")
+	}
+	if !caps.DryRun {
+		t.Error("expected DryRun=true")
+	}
+	// Should be false
+	if caps.Hold {
+		t.Error("expected Hold=false")
+	}
+	if caps.RepoManagement {
+		t.Error("expected RepoManagement=false")
+	}
+	if caps.KeyManagement {
+		t.Error("expected KeyManagement=false")
+	}
+	if caps.Groups {
+		t.Error("expected Groups=false")
+	}
+	if caps.NameNormalize {
+		t.Error("expected NameNormalize=false")
+	}
+	if !caps.PackageUpgrade {
+		t.Error("expected PackageUpgrade=true")
+	}
+}
+
+func TestSupportsDryRun(t *testing.T) {
+	a := New()
+	if !a.SupportsDryRun() {
+		t.Error("SupportsDryRun() should return true")
+	}
+}
+
+func TestParseUpgradeSimulation(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		wantLen  int
+		wantPkgs []snack.Package
+	}{
+		{
+			name:    "empty",
+			input:   "",
+			wantLen: 0,
+		},
+		{
+			name:    "OK only",
+			input:   "OK: 123 MiB in 45 packages\n",
+			wantLen: 0,
+		},
+		{
+			name:  "single upgrade",
+			input: "(1/1) Upgrading curl (8.5.0-r0 -> 8.6.0-r0)\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "curl", Version: "8.6.0-r0", Installed: true},
+			},
+		},
+		{
+			name: "multiple upgrades",
+			input: `(1/3) Upgrading musl (1.2.4-r2 -> 1.2.5-r0)
+(2/3) Upgrading openssl (3.1.4-r0 -> 3.2.0-r0)
+(3/3) Upgrading curl (8.5.0-r0 -> 8.6.0-r0)
+OK: 123 MiB in 45 packages
+`,
+			wantLen: 3,
+			wantPkgs: []snack.Package{
+				{Name: "musl", Version: "1.2.5-r0", Installed: true},
+				{Name: "openssl", Version: "3.2.0-r0", Installed: true},
+				{Name: "curl", Version: "8.6.0-r0", Installed: true},
+			},
+		},
+		{
+			name:    "non-upgrade lines only",
+			input:   "Purging old package\nInstalling new-pkg\n",
+			wantLen: 0,
+		},
+		{
+			name:  "upgrade without version parens",
+			input: "(1/1) Upgrading busybox\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "busybox", Version: "", Installed: true},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkgs := parseUpgradeSimulation(tt.input)
+			if len(pkgs) != tt.wantLen {
+				t.Fatalf("expected %d packages, got %d", tt.wantLen, len(pkgs))
+			}
+			for i, want := range tt.wantPkgs {
+				if i >= len(pkgs) {
+					break
+				}
+				if pkgs[i].Name != want.Name {
+					t.Errorf("pkg[%d].Name = %q, want %q", i, pkgs[i].Name, want.Name)
+				}
+				if pkgs[i].Version != want.Version {
+					t.Errorf("pkg[%d].Version = %q, want %q", i, pkgs[i].Version, want.Version)
+				}
+				if pkgs[i].Installed != want.Installed {
+					t.Errorf("pkg[%d].Installed = %v, want %v", i, pkgs[i].Installed, want.Installed)
+				}
+			}
+		})
+	}
+}

apk/parse.go

@@ -127,10 +127,12 @@ func parseInfo(output string) *snack.Package {
 // The first line is typically "pkgname-version description".
 func parseInfoNameVersion(output string) (string, string) {
 	lines := strings.Split(strings.TrimSpace(output), "\n")
-	if len(lines) == 0 {
+	if len(lines) == 0 || lines[0] == "" {
 		return "", ""
 	}
-	// first line: name-version
-	first := strings.Fields(lines[0])[0]
-	return splitNameVersion(first)
+	fields := strings.Fields(lines[0])
+	if len(fields) == 0 {
+		return "", ""
+	}
+	return splitNameVersion(fields[0])
 }

apt/apt_test.go

@@ -67,5 +67,50 @@ func TestNew(t *testing.T) {
 	}
 }
 
-// Verify Apt implements snack.Manager at compile time.
-var _ snack.Manager = (*Apt)(nil)
+func TestSupportsDryRun(t *testing.T) {
+	a := New()
+	if !a.SupportsDryRun() {
+		t.Error("expected SupportsDryRun() = true")
+	}
+}
+
+func TestCapabilities(t *testing.T) {
+	caps := snack.GetCapabilities(New())
+	checks := []struct {
+		name string
+		got  bool
+		want bool
+	}{
+		{"VersionQuery", caps.VersionQuery, true},
+		{"Hold", caps.Hold, true},
+		{"Clean", caps.Clean, true},
+		{"FileOwnership", caps.FileOwnership, true},
+		{"RepoManagement", caps.RepoManagement, true},
+		{"KeyManagement", caps.KeyManagement, true},
+		{"Groups", caps.Groups, false},
+		{"NameNormalize", caps.NameNormalize, true},
+		{"DryRun", caps.DryRun, true},
+		{"PackageUpgrade", caps.PackageUpgrade, true},
+	}
+	for _, c := range checks {
+		t.Run(c.name, func(t *testing.T) {
+			if c.got != c.want {
+				t.Errorf("Capabilities.%s = %v, want %v", c.name, c.got, c.want)
+			}
+		})
+	}
+}
+
+// Compile-time interface checks.
+var (
+	_ snack.Manager         = (*Apt)(nil)
+	_ snack.VersionQuerier  = (*Apt)(nil)
+	_ snack.Holder          = (*Apt)(nil)
+	_ snack.Cleaner         = (*Apt)(nil)
+	_ snack.FileOwner       = (*Apt)(nil)
+	_ snack.RepoManager     = (*Apt)(nil)
+	_ snack.KeyManager      = (*Apt)(nil)
+	_ snack.NameNormalizer  = (*Apt)(nil)
+	_ snack.DryRunner       = (*Apt)(nil)
+	_ snack.PackageUpgrader = (*Apt)(nil)
+)

apt/capabilities_linux.go

@@ -23,17 +23,11 @@ func latestVersion(ctx context.Context, pkg string) (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("apt-cache policy %s: %w", pkg, snack.ErrNotFound)
 	}
-	for _, line := range strings.Split(string(out), "\n") {
-		line = strings.TrimSpace(line)
-		if strings.HasPrefix(line, "Candidate:") {
-			candidate := strings.TrimSpace(strings.TrimPrefix(line, "Candidate:"))
-			if candidate == "(none)" {
-				return "", fmt.Errorf("apt-cache policy %s: %w", pkg, snack.ErrNotFound)
-			}
-			return candidate, nil
-		}
+	candidate := parsePolicyCandidate(string(out))
+	if candidate == "" {
+		return "", fmt.Errorf("apt-cache policy %s: %w", pkg, snack.ErrNotFound)
 	}
-	return "", fmt.Errorf("apt-cache policy %s: %w", pkg, snack.ErrNotFound)
+	return candidate, nil
 }
 
 func listUpgrades(ctx context.Context) ([]snack.Package, error) {
@@ -45,38 +39,7 @@ func listUpgrades(ctx context.Context) ([]snack.Package, error) {
 	if err != nil {
 		return nil, fmt.Errorf("apt-get --just-print upgrade: %w", err)
 	}
-	var pkgs []snack.Package
-	for _, line := range strings.Split(string(out), "\n") {
-		line = strings.TrimSpace(line)
-		// Lines starting with "Inst " indicate upgradable packages.
-		// Format: "Inst pkg [old-ver] (new-ver repo [arch])"
-		if !strings.HasPrefix(line, "Inst ") {
-			continue
-		}
-		line = strings.TrimPrefix(line, "Inst ")
-		fields := strings.Fields(line)
-		if len(fields) < 2 {
-			continue
-		}
-		name := fields[0]
-		// Find the new version in parentheses
-		parenStart := strings.Index(line, "(")
-		parenEnd := strings.Index(line, ")")
-		if parenStart < 0 || parenEnd < 0 {
-			continue
-		}
-		verFields := strings.Fields(line[parenStart+1 : parenEnd])
-		if len(verFields) < 1 {
-			continue
-		}
-		p := snack.Package{
-			Name:      name,
-			Version:   verFields[0],
-			Installed: true,
-		}
-		pkgs = append(pkgs, p)
-	}
-	return pkgs, nil
+	return parseUpgradeSimulation(string(out)), nil
 }
 
 func upgradeAvailable(ctx context.Context, pkg string) (bool, error) {
@@ -85,19 +48,12 @@ func upgradeAvailable(ctx context.Context, pkg string) (bool, error) {
 	if err != nil {
 		return false, fmt.Errorf("apt-cache policy %s: %w", pkg, snack.ErrNotFound)
 	}
-	var installed, candidate string
-	for _, line := range strings.Split(string(out), "\n") {
-		line = strings.TrimSpace(line)
-		if strings.HasPrefix(line, "Installed:") {
-			installed = strings.TrimSpace(strings.TrimPrefix(line, "Installed:"))
-		} else if strings.HasPrefix(line, "Candidate:") {
-			candidate = strings.TrimSpace(strings.TrimPrefix(line, "Candidate:"))
-		}
-	}
-	if installed == "(none)" || installed == "" {
+	installed := parsePolicyInstalled(string(out))
+	candidate := parsePolicyCandidate(string(out))
+	if installed == "" {
 		return false, fmt.Errorf("apt-cache policy %s: %w", pkg, snack.ErrNotInstalled)
 	}
-	if candidate == "(none)" || candidate == "" || candidate == installed {
+	if candidate == "" || candidate == installed {
 		return false, nil
 	}
 	return true, nil
@@ -148,15 +104,7 @@ func listHeld(ctx context.Context) ([]snack.Package, error) {
 	if err != nil {
 		return nil, fmt.Errorf("apt-mark showhold: %w", err)
 	}
-	var pkgs []snack.Package
-	for _, line := range strings.Split(strings.TrimSpace(string(out)), "\n") {
-		line = strings.TrimSpace(line)
-		if line == "" {
-			continue
-		}
-		pkgs = append(pkgs, snack.Package{Name: line, Installed: true})
-	}
-	return pkgs, nil
+	return parseHoldList(string(out)), nil
 }
 
 func isHeld(ctx context.Context, pkg string) (bool, error) {
@@ -198,14 +146,7 @@ func fileList(ctx context.Context, pkg string) ([]string, error) {
 		}
 		return nil, fmt.Errorf("dpkg-query -L %s: %w: %s", pkg, err, errMsg)
 	}
-	var files []string
-	for _, line := range strings.Split(strings.TrimSpace(string(out)), "\n") {
-		line = strings.TrimSpace(line)
-		if line != "" {
-			files = append(files, line)
-		}
-	}
-	return files, nil
+	return parseFileList(string(out)), nil
 }
 
 func owner(ctx context.Context, path string) (string, error) {
@@ -216,18 +157,11 @@ func owner(ctx context.Context, path string) (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("dpkg -S %s: %w", path, snack.ErrNotFound)
 	}
-	// Output format: "package: /path/to/file" or "package1, package2: /path"
-	line := strings.TrimSpace(strings.Split(string(out), "\n")[0])
-	colonIdx := strings.Index(line, ":")
-	if colonIdx < 0 {
+	pkg := parseOwner(string(out))
+	if pkg == "" {
 		return "", fmt.Errorf("dpkg -S %s: unexpected output", path)
 	}
-	// Return first package if multiple
-	pkgPart := line[:colonIdx]
-	if commaIdx := strings.Index(pkgPart, ","); commaIdx >= 0 {
-		pkgPart = strings.TrimSpace(pkgPart[:commaIdx])
-	}
-	return strings.TrimSpace(pkgPart), nil
+	return pkg, nil
 }
 
 // --- RepoManager ---
@@ -249,51 +183,14 @@ func listRepos(_ context.Context) ([]snack.Repository, error) {
 		}
 		scanner := bufio.NewScanner(bytes.NewReader(data))
 		for scanner.Scan() {
-			line := strings.TrimSpace(scanner.Text())
-			if line == "" || strings.HasPrefix(line, "#") {
-				continue
-			}
-			enabled := true
-			// deb822 format (.sources files) not fully parsed; treat as single entry
-			if strings.HasPrefix(line, "deb ") || strings.HasPrefix(line, "deb-src ") {
-				repos = append(repos, snack.Repository{
-					ID:      line,
-					URL:     extractURL(line),
-					Enabled: enabled,
-					Type:    strings.Fields(line)[0],
-				})
+			if r := parseSourcesLine(scanner.Text()); r != nil {
+				repos = append(repos, *r)
 			}
 		}
 	}
 	return repos, nil
 }
 
-// extractURL pulls the URL from a deb/deb-src line.
-func extractURL(line string) string {
-	fields := strings.Fields(line)
-	inOptions := false
-	for i, f := range fields {
-		if i == 0 {
-			continue // skip deb/deb-src
-		}
-		if inOptions {
-			if strings.HasSuffix(f, "]") {
-				inOptions = false
-			}
-			continue
-		}
-		if strings.HasPrefix(f, "[") {
-			if strings.HasSuffix(f, "]") {
-				// Single-token options like [arch=amd64]
-				continue
-			}
-			inOptions = true
-			continue
-		}
-		return f
-	}
-	return ""
-}
 
 func addRepo(ctx context.Context, repo snack.Repository) error {
 	repoLine := repo.URL

apt/helpers_linux_test.go

@@ -150,50 +150,3 @@ func TestBuildArgs(t *testing.T) {
 		})
 	}
 }
-
-func TestExtractURL(t *testing.T) {
-	tests := []struct {
-		name  string
-		input string
-		want  string
-	}{
-		{
-			name:  "basic_deb",
-			input: "deb http://archive.ubuntu.com/ubuntu/ jammy main",
-			want:  "http://archive.ubuntu.com/ubuntu/",
-		},
-		{
-			name:  "deb_src",
-			input: "deb-src http://archive.ubuntu.com/ubuntu/ jammy main",
-			want:  "http://archive.ubuntu.com/ubuntu/",
-		},
-		{
-			name:  "with_options",
-			input: "deb [arch=amd64] https://apt.example.com/repo stable main",
-			want:  "https://apt.example.com/repo",
-		},
-		{
-			name:  "with_signed_by",
-			input: "deb [arch=amd64 signed-by=/etc/apt/keyrings/key.gpg] https://repo.example.com/deb stable main",
-			want:  "https://repo.example.com/deb",
-		},
-		{
-			name:  "just_type",
-			input: "deb",
-			want:  "",
-		},
-		{
-			name:  "empty_options_bracket",
-			input: "deb [] http://example.com/repo stable",
-			want:  "http://example.com/repo",
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got := extractURL(tt.input)
-			if got != tt.want {
-				t.Errorf("extractURL(%q) = %q, want %q", tt.input, got, tt.want)
-			}
-		})
-	}
-}

apt/parse.go

@@ -51,6 +51,158 @@ func parseSearch(output string) []snack.Package {
 	return pkgs
 }
 
+// parsePolicyCandidate extracts the Candidate version from apt-cache policy output.
+// Returns empty string if no candidate is found or candidate is "(none)".
+func parsePolicyCandidate(output string) string {
+	for _, line := range strings.Split(output, "\n") {
+		line = strings.TrimSpace(line)
+		if strings.HasPrefix(line, "Candidate:") {
+			candidate := strings.TrimSpace(strings.TrimPrefix(line, "Candidate:"))
+			if candidate == "(none)" {
+				return ""
+			}
+			return candidate
+		}
+	}
+	return ""
+}
+
+// parsePolicyInstalled extracts the Installed version from apt-cache policy output.
+// Returns empty string if not installed or "(none)".
+func parsePolicyInstalled(output string) string {
+	for _, line := range strings.Split(output, "\n") {
+		line = strings.TrimSpace(line)
+		if strings.HasPrefix(line, "Installed:") {
+			installed := strings.TrimSpace(strings.TrimPrefix(line, "Installed:"))
+			if installed == "(none)" {
+				return ""
+			}
+			return installed
+		}
+	}
+	return ""
+}
+
+// parseUpgradeSimulation parses apt-get --just-print upgrade output.
+// Lines starting with "Inst " indicate upgradable packages.
+// Format: "Inst pkg [old-ver] (new-ver repo [arch])"
+func parseUpgradeSimulation(output string) []snack.Package {
+	var pkgs []snack.Package
+	for _, line := range strings.Split(output, "\n") {
+		line = strings.TrimSpace(line)
+		if !strings.HasPrefix(line, "Inst ") {
+			continue
+		}
+		line = strings.TrimPrefix(line, "Inst ")
+		fields := strings.Fields(line)
+		if len(fields) < 2 {
+			continue
+		}
+		name := fields[0]
+		parenStart := strings.Index(line, "(")
+		parenEnd := strings.Index(line, ")")
+		if parenStart < 0 || parenEnd < 0 {
+			continue
+		}
+		verFields := strings.Fields(line[parenStart+1 : parenEnd])
+		if len(verFields) < 1 {
+			continue
+		}
+		pkgs = append(pkgs, snack.Package{
+			Name:      name,
+			Version:   verFields[0],
+			Installed: true,
+		})
+	}
+	return pkgs
+}
+
+// parseHoldList parses apt-mark showhold output (one package name per line).
+func parseHoldList(output string) []snack.Package {
+	var pkgs []snack.Package
+	for _, line := range strings.Split(strings.TrimSpace(output), "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+		pkgs = append(pkgs, snack.Package{Name: line, Installed: true})
+	}
+	return pkgs
+}
+
+// parseFileList parses dpkg-query -L output (one file path per line).
+func parseFileList(output string) []string {
+	var files []string
+	for _, line := range strings.Split(strings.TrimSpace(output), "\n") {
+		line = strings.TrimSpace(line)
+		if line != "" {
+			files = append(files, line)
+		}
+	}
+	return files
+}
+
+// parseOwner parses dpkg -S output to extract the owning package name.
+// Output format: "package: /path/to/file" or "pkg1, pkg2: /path".
+// Returns the first package name.
+func parseOwner(output string) string {
+	line := strings.TrimSpace(strings.Split(output, "\n")[0])
+	colonIdx := strings.Index(line, ":")
+	if colonIdx < 0 {
+		return ""
+	}
+	pkgPart := line[:colonIdx]
+	if commaIdx := strings.Index(pkgPart, ","); commaIdx >= 0 {
+		pkgPart = strings.TrimSpace(pkgPart[:commaIdx])
+	}
+	return strings.TrimSpace(pkgPart)
+}
+
+// parseSourcesLine parses a single deb/deb-src line from sources.list.
+// Returns a Repository if the line is valid, or nil if it's a comment/blank.
+func parseSourcesLine(line string) *snack.Repository {
+	line = strings.TrimSpace(line)
+	if line == "" || strings.HasPrefix(line, "#") {
+		return nil
+	}
+	if !strings.HasPrefix(line, "deb ") && !strings.HasPrefix(line, "deb-src ") {
+		return nil
+	}
+	return &snack.Repository{
+		ID:      line,
+		URL:     extractURL(line),
+		Enabled: true,
+		Type:    strings.Fields(line)[0],
+	}
+}
+
+// extractURL pulls the URL from a deb/deb-src line.
+func extractURL(line string) string {
+	fields := strings.Fields(line)
+	inOptions := false
+	for i, f := range fields {
+		if i == 0 {
+			continue // skip deb/deb-src
+		}
+		if inOptions {
+			if strings.HasSuffix(f, "]") {
+				inOptions = false
+			}
+			continue
+		}
+		if strings.HasPrefix(f, "[") {
+			if strings.HasSuffix(f, "]") {
+				// Single-token options like [arch=amd64]
+				continue
+			}
+			inOptions = true
+			continue
+		}
+		return f
+	}
+	return ""
+}
+
 // parseInfo parses apt-cache show output into a Package.
 func parseInfo(output string) (*snack.Package, error) {
 	p := &snack.Package{}

apt/parse_test.go

@@ -194,3 +194,445 @@ func TestParseInfo_EdgeCases(t *testing.T) {
 		}
 	})
 }
+
+// --- New parse function tests ---
+
+func TestParsePolicyCandidate(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{
+			name: "normal_policy_output",
+			input: `bash:
+  Installed: 5.2-1
+  Candidate: 5.2-2
+  Version table:
+     5.2-2 500
+        500 http://archive.ubuntu.com/ubuntu jammy/main amd64 Packages
+ *** 5.2-1 100
+        100 /var/lib/dpkg/status`,
+			want: "5.2-2",
+		},
+		{
+			name: "candidate_none",
+			input: `virtual-pkg:
+  Installed: (none)
+  Candidate: (none)
+  Version table:`,
+			want: "",
+		},
+		{
+			name:  "empty_input",
+			input: "",
+			want:  "",
+		},
+		{
+			name: "installed_equals_candidate",
+			input: `curl:
+  Installed: 7.88.1-10+deb12u4
+  Candidate: 7.88.1-10+deb12u4
+  Version table:
+ *** 7.88.1-10+deb12u4 500`,
+			want: "7.88.1-10+deb12u4",
+		},
+		{
+			name: "epoch_version",
+			input: `systemd:
+  Installed: 1:252-2
+  Candidate: 1:252-3
+  Version table:`,
+			want: "1:252-3",
+		},
+		{
+			name:  "no_candidate_line",
+			input: "bash:\n  Installed: 5.2-1\n",
+			want:  "",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := parsePolicyCandidate(tt.input)
+			if got != tt.want {
+				t.Errorf("parsePolicyCandidate() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestParsePolicyInstalled(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{
+			name: "normal",
+			input: `bash:
+  Installed: 5.2-1
+  Candidate: 5.2-2`,
+			want: "5.2-1",
+		},
+		{
+			name: "not_installed",
+			input: `foo:
+  Installed: (none)
+  Candidate: 1.0`,
+			want: "",
+		},
+		{
+			name:  "empty",
+			input: "",
+			want:  "",
+		},
+		{
+			name: "epoch_version",
+			input: `systemd:
+  Installed: 1:252-2
+  Candidate: 1:252-3`,
+			want: "1:252-2",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := parsePolicyInstalled(tt.input)
+			if got != tt.want {
+				t.Errorf("parsePolicyInstalled() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestParseUpgradeSimulation(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  []snack.Package
+	}{
+		{
+			name:  "empty",
+			input: "",
+			want:  nil,
+		},
+		{
+			name: "single_upgrade",
+			input: `Reading package lists...
+Building dependency tree...
+Reading state information...
+The following packages will be upgraded:
+  bash
+1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
+Inst bash [5.2-1] (5.2-2 Ubuntu:22.04/jammy [amd64])
+Conf bash (5.2-2 Ubuntu:22.04/jammy [amd64])`,
+			want: []snack.Package{
+				{Name: "bash", Version: "5.2-2", Installed: true},
+			},
+		},
+		{
+			name: "multiple_upgrades",
+			input: `Inst bash [5.2-1] (5.2-2 Ubuntu:22.04/jammy [amd64])
+Inst curl [7.88.0] (7.88.1 Ubuntu:22.04/jammy [amd64])
+Inst systemd [1:252-1] (1:252-2 Ubuntu:22.04/jammy [amd64])
+Conf bash (5.2-2 Ubuntu:22.04/jammy [amd64])
+Conf curl (7.88.1 Ubuntu:22.04/jammy [amd64])
+Conf systemd (1:252-2 Ubuntu:22.04/jammy [amd64])`,
+			want: []snack.Package{
+				{Name: "bash", Version: "5.2-2", Installed: true},
+				{Name: "curl", Version: "7.88.1", Installed: true},
+				{Name: "systemd", Version: "1:252-2", Installed: true},
+			},
+		},
+		{
+			name:  "no_inst_lines",
+			input: "Reading package lists...\nBuilding dependency tree...\n0 upgraded, 0 newly installed.\n",
+			want:  nil,
+		},
+		{
+			name:  "inst_without_parens",
+			input: "Inst bash no-parens-here\n",
+			want:  nil,
+		},
+		{
+			name:  "inst_with_empty_parens",
+			input: "Inst bash [5.2-1] ()\n",
+			want:  nil,
+		},
+		{
+			name:  "conf_lines_ignored",
+			input: "Conf bash (5.2-2 Ubuntu:22.04/jammy [amd64])\n",
+			want:  nil,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := parseUpgradeSimulation(tt.input)
+			if len(got) != len(tt.want) {
+				t.Fatalf("parseUpgradeSimulation() returned %d packages, want %d", len(got), len(tt.want))
+			}
+			for i, g := range got {
+				w := tt.want[i]
+				if g.Name != w.Name || g.Version != w.Version || g.Installed != w.Installed {
+					t.Errorf("package[%d] = %+v, want %+v", i, g, w)
+				}
+			}
+		})
+	}
+}
+
+func TestParseHoldList(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  []string
+	}{
+		{"empty", "", nil},
+		{"whitespace_only", "  \n  \n", nil},
+		{"single_package", "bash\n", []string{"bash"}},
+		{"multiple_packages", "bash\ncurl\nnginx\n", []string{"bash", "curl", "nginx"}},
+		{"blank_lines_mixed", "\nbash\n\ncurl\n\n", []string{"bash", "curl"}},
+		{"trailing_whitespace", "  bash  \n  curl  \n", []string{"bash", "curl"}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkgs := parseHoldList(tt.input)
+			var names []string
+			for _, p := range pkgs {
+				names = append(names, p.Name)
+				if !p.Installed {
+					t.Errorf("expected Installed=true for %q", p.Name)
+				}
+			}
+			if len(names) != len(tt.want) {
+				t.Fatalf("got %d packages, want %d", len(names), len(tt.want))
+			}
+			for i, n := range names {
+				if n != tt.want[i] {
+					t.Errorf("package[%d] = %q, want %q", i, n, tt.want[i])
+				}
+			}
+		})
+	}
+}
+
+func TestParseFileList(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  []string
+	}{
+		{"empty", "", nil},
+		{"whitespace_only", "  \n\n  ", nil},
+		{
+			name:  "single_file",
+			input: "/usr/bin/bash\n",
+			want:  []string{"/usr/bin/bash"},
+		},
+		{
+			name:  "multiple_files",
+			input: "/.\n/usr\n/usr/bin\n/usr/bin/bash\n/usr/share/man/man1/bash.1.gz\n",
+			want:  []string{"/.", "/usr", "/usr/bin", "/usr/bin/bash", "/usr/share/man/man1/bash.1.gz"},
+		},
+		{
+			name:  "blank_lines_mixed",
+			input: "\n/usr/bin/curl\n\n/usr/share/doc/curl\n\n",
+			want:  []string{"/usr/bin/curl", "/usr/share/doc/curl"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := parseFileList(tt.input)
+			if len(got) != len(tt.want) {
+				t.Fatalf("parseFileList() returned %d files, want %d", len(got), len(tt.want))
+			}
+			for i, f := range got {
+				if f != tt.want[i] {
+					t.Errorf("file[%d] = %q, want %q", i, f, tt.want[i])
+				}
+			}
+		})
+	}
+}
+
+func TestParseOwner(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{
+			name:  "single_package",
+			input: "bash: /usr/bin/bash\n",
+			want:  "bash",
+		},
+		{
+			name:  "multiple_packages",
+			input: "bash, dash: /usr/bin/sh\n",
+			want:  "bash",
+		},
+		{
+			name:  "package_with_arch",
+			input: "libc6:amd64: /lib/x86_64-linux-gnu/libc.so.6\n",
+			want:  "libc6", // parseOwner splits on first colon, arch suffix is stripped
+		},
+		{
+			name:  "multiple_lines",
+			input: "coreutils: /usr/bin/ls\ncoreutils: /usr/bin/cat\n",
+			want:  "coreutils",
+		},
+		{
+			name:  "no_colon",
+			input: "unexpected output without colon",
+			want:  "",
+		},
+		{
+			name:  "empty",
+			input: "",
+			want:  "",
+		},
+		{
+			name:  "whitespace_around_package",
+			input: "  nginx  : /usr/sbin/nginx\n",
+			want:  "nginx",
+		},
+		{
+			name:  "three_packages_comma_separated",
+			input: "pkg1, pkg2, pkg3: /some/path\n",
+			want:  "pkg1",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := parseOwner(tt.input)
+			if got != tt.want {
+				t.Errorf("parseOwner() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestParseSourcesLine(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		wantNil bool
+		wantURL string
+		wantTyp string
+	}{
+		{
+			name:    "empty",
+			input:   "",
+			wantNil: true,
+		},
+		{
+			name:    "comment",
+			input:   "# This is a comment",
+			wantNil: true,
+		},
+		{
+			name:    "non_deb_line",
+			input:   "some random text",
+			wantNil: true,
+		},
+		{
+			name:    "basic_deb",
+			input:   "deb http://archive.ubuntu.com/ubuntu/ jammy main",
+			wantURL: "http://archive.ubuntu.com/ubuntu/",
+			wantTyp: "deb",
+		},
+		{
+			name:    "deb_src",
+			input:   "deb-src http://archive.ubuntu.com/ubuntu/ jammy main",
+			wantURL: "http://archive.ubuntu.com/ubuntu/",
+			wantTyp: "deb-src",
+		},
+		{
+			name:    "with_options",
+			input:   "deb [arch=amd64] https://repo.example.com/deb stable main",
+			wantURL: "https://repo.example.com/deb",
+			wantTyp: "deb",
+		},
+		{
+			name:    "with_signed_by",
+			input:   "deb [arch=amd64 signed-by=/etc/apt/keyrings/key.gpg] https://repo.example.com stable main",
+			wantURL: "https://repo.example.com",
+			wantTyp: "deb",
+		},
+		{
+			name:    "leading_whitespace",
+			input:   "   deb http://example.com/repo stable main",
+			wantURL: "http://example.com/repo",
+			wantTyp: "deb",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			r := parseSourcesLine(tt.input)
+			if tt.wantNil {
+				if r != nil {
+					t.Errorf("parseSourcesLine() = %+v, want nil", r)
+				}
+				return
+			}
+			if r == nil {
+				t.Fatal("parseSourcesLine() = nil, want non-nil")
+			}
+			if r.URL != tt.wantURL {
+				t.Errorf("URL = %q, want %q", r.URL, tt.wantURL)
+			}
+			if r.Type != tt.wantTyp {
+				t.Errorf("Type = %q, want %q", r.Type, tt.wantTyp)
+			}
+			if !r.Enabled {
+				t.Error("expected Enabled=true")
+			}
+		})
+	}
+}
+
+func TestExtractURL(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{
+			name:  "basic_deb",
+			input: "deb http://archive.ubuntu.com/ubuntu/ jammy main",
+			want:  "http://archive.ubuntu.com/ubuntu/",
+		},
+		{
+			name:  "deb_src",
+			input: "deb-src http://archive.ubuntu.com/ubuntu/ jammy main",
+			want:  "http://archive.ubuntu.com/ubuntu/",
+		},
+		{
+			name:  "with_options",
+			input: "deb [arch=amd64] https://apt.example.com/repo stable main",
+			want:  "https://apt.example.com/repo",
+		},
+		{
+			name:  "with_signed_by",
+			input: "deb [arch=amd64 signed-by=/etc/apt/keyrings/key.gpg] https://repo.example.com/deb stable main",
+			want:  "https://repo.example.com/deb",
+		},
+		{
+			name:  "just_type",
+			input: "deb",
+			want:  "",
+		},
+		{
+			name:  "empty_options_bracket",
+			input: "deb [] http://example.com/repo stable",
+			want:  "http://example.com/repo",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := extractURL(tt.input)
+			if got != tt.want {
+				t.Errorf("extractURL(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}

aur/aur_test.go

@@ -3,7 +3,9 @@ package aur
 import (
 	"testing"
 
+	"github.com/gogrlx/snack"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestParsePackageList(t *testing.T) {
@@ -63,3 +65,142 @@ func TestNewWithOptions(t *testing.T) {
 	assert.Equal(t, "/tmp/aur-builds", a.BuildDir)
 	assert.Equal(t, []string{"--skippgpcheck", "--nocheck"}, a.MakepkgFlags)
 }
+
+func TestInterfaceCompliance(t *testing.T) {
+	var _ snack.Manager = (*AUR)(nil)
+	var _ snack.VersionQuerier = (*AUR)(nil)
+	var _ snack.Cleaner = (*AUR)(nil)
+	var _ snack.PackageUpgrader = (*AUR)(nil)
+}
+
+func TestInterfaceNonCompliance(t *testing.T) {
+	a := New()
+	var m snack.Manager = a
+
+	if _, ok := m.(snack.FileOwner); ok {
+		t.Error("AUR should not implement FileOwner")
+	}
+	if _, ok := m.(snack.Holder); ok {
+		t.Error("AUR should not implement Holder")
+	}
+	if _, ok := m.(snack.RepoManager); ok {
+		t.Error("AUR should not implement RepoManager")
+	}
+	if _, ok := m.(snack.KeyManager); ok {
+		t.Error("AUR should not implement KeyManager")
+	}
+	if _, ok := m.(snack.Grouper); ok {
+		t.Error("AUR should not implement Grouper")
+	}
+	if _, ok := m.(snack.NameNormalizer); ok {
+		t.Error("AUR should not implement NameNormalizer")
+	}
+	if _, ok := m.(snack.DryRunner); ok {
+		t.Error("AUR should not implement DryRunner")
+	}
+}
+
+func TestCapabilities(t *testing.T) {
+	caps := snack.GetCapabilities(New())
+
+	tests := []struct {
+		name string
+		got  bool
+		want bool
+	}{
+		{"VersionQuery", caps.VersionQuery, true},
+		{"Clean", caps.Clean, true},
+		{"FileOwnership", caps.FileOwnership, false},
+		{"Hold", caps.Hold, false},
+		{"RepoManagement", caps.RepoManagement, false},
+		{"KeyManagement", caps.KeyManagement, false},
+		{"Groups", caps.Groups, false},
+		{"NameNormalize", caps.NameNormalize, false},
+		{"DryRun", caps.DryRun, false},
+		{"PackageUpgrade", caps.PackageUpgrade, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.got != tt.want {
+				t.Errorf("%s = %v, want %v", tt.name, tt.got, tt.want)
+			}
+		})
+	}
+}
+
+func TestName(t *testing.T) {
+	a := New()
+	assert.Equal(t, "aur", a.Name())
+}
+
+func TestParsePackageList_EdgeCases(t *testing.T) {
+	tests := []struct {
+		name      string
+		input     string
+		wantLen   int
+		wantNames []string
+		wantVers  []string
+	}{
+		{
+			name:    "empty string",
+			input:   "",
+			wantLen: 0,
+		},
+		{
+			name:    "whitespace only",
+			input:   "  \n\t\n  \n",
+			wantLen: 0,
+		},
+		{
+			name:      "single package",
+			input:     "yay 12.5.7-1\n",
+			wantLen:   1,
+			wantNames: []string{"yay"},
+			wantVers:  []string{"12.5.7-1"},
+		},
+		{
+			name:    "malformed single field",
+			input:   "orphan\n",
+			wantLen: 0,
+		},
+		{
+			name:      "malformed mixed with valid",
+			input:     "orphan\nyay 12.5.7-1\nbadline\nparu 2.0-1\n",
+			wantLen:   2,
+			wantNames: []string{"yay", "paru"},
+			wantVers:  []string{"12.5.7-1", "2.0-1"},
+		},
+		{
+			name:      "extra fields ignored",
+			input:     "yay 12.5.7-1 extra stuff\n",
+			wantLen:   1,
+			wantNames: []string{"yay"},
+			wantVers:  []string{"12.5.7-1"},
+		},
+		{
+			name:      "trailing and leading whitespace on lines",
+			input:     "  yay 12.5.7-1  \n  paru 2.0.4-1\n\n",
+			wantLen:   2,
+			wantNames: []string{"yay", "paru"},
+			wantVers:  []string{"12.5.7-1", "2.0.4-1"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkgs := parsePackageList(tt.input)
+			require.Len(t, pkgs, tt.wantLen)
+			for i, p := range pkgs {
+				assert.Equal(t, "aur", p.Repository, "all packages should have Repository=aur")
+				assert.True(t, p.Installed, "all packages should have Installed=true")
+				if i < len(tt.wantNames) {
+					assert.Equal(t, tt.wantNames[i], p.Name)
+				}
+				if i < len(tt.wantVers) {
+					assert.Equal(t, tt.wantVers[i], p.Version)
+				}
+			}
+		})
+	}
+}

capabilities.go

@@ -4,15 +4,16 @@ package snack
 // Useful for grlx to determine what operations are available before
 // attempting them.
 type Capabilities struct {
-	VersionQuery   bool
-	Hold           bool
-	Clean          bool
-	FileOwnership  bool
-	RepoManagement bool
-	KeyManagement  bool
-	Groups         bool
-	NameNormalize  bool
-	DryRun         bool
+	VersionQuery    bool
+	Hold            bool
+	Clean           bool
+	FileOwnership   bool
+	RepoManagement  bool
+	KeyManagement   bool
+	Groups          bool
+	NameNormalize   bool
+	DryRun          bool
+	PackageUpgrade  bool
 }
 
 // GetCapabilities probes a Manager for all optional interface support.
@@ -26,15 +27,17 @@ func GetCapabilities(m Manager) Capabilities {
 	_, g := m.(Grouper)
 	_, nn := m.(NameNormalizer)
 	_, dr := m.(DryRunner)
+	_, pu := m.(PackageUpgrader)
 	return Capabilities{
-		VersionQuery:   vq,
-		Hold:           h,
-		Clean:          c,
-		FileOwnership:  fo,
-		RepoManagement: rm,
-		KeyManagement:  km,
-		Groups:         g,
-		NameNormalize:  nn,
-		DryRun:         dr,
+		VersionQuery:    vq,
+		Hold:            h,
+		Clean:           c,
+		FileOwnership:   fo,
+		RepoManagement:  rm,
+		KeyManagement:   km,
+		Groups:          g,
+		NameNormalize:   nn,
+		DryRun:          dr,
+		PackageUpgrade:  pu,
 	}
 }

capabilities_test.go

@@ -77,6 +77,7 @@ func TestGetCapabilities_BaseManager(t *testing.T) {
 	assert.False(t, caps.Groups)
 	assert.False(t, caps.NameNormalize)
 	assert.False(t, caps.DryRun)
+	assert.False(t, caps.PackageUpgrade)
 }
 
 func TestGetCapabilities_FullManager(t *testing.T) {
@@ -90,4 +91,5 @@ func TestGetCapabilities_FullManager(t *testing.T) {
 	assert.True(t, caps.Groups)
 	assert.True(t, caps.NameNormalize)
 	assert.True(t, caps.DryRun)
+	assert.True(t, caps.PackageUpgrade)
 }

cmd/snack/main.go

@@ -387,6 +387,9 @@ func detectCmd() *cobra.Command {
 				if caps.NameNormalize {
 					capList = append(capList, "normalize")
 				}
+				if caps.PackageUpgrade {
+					capList = append(capList, "pkg-upgrade")
+				}
 				capStr := ""
 				if len(capList) > 0 {
 					capStr = " [" + strings.Join(capList, ", ") + "]"

cmd/snack/main_test.go

@@ -0,0 +1,149 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/gogrlx/snack"
+)
+
+func TestTargets(t *testing.T) {
+	tests := []struct {
+		name string
+		args []string
+		ver  string
+		want []snack.Target
+	}{
+		{
+			name: "no_args",
+			args: nil,
+			want: nil,
+		},
+		{
+			name: "single_no_version",
+			args: []string{"curl"},
+			want: []snack.Target{{Name: "curl"}},
+		},
+		{
+			name: "multiple_no_version",
+			args: []string{"curl", "wget"},
+			want: []snack.Target{{Name: "curl"}, {Name: "wget"}},
+		},
+		{
+			name: "single_with_version",
+			args: []string{"curl"},
+			ver:  "7.88",
+			want: []snack.Target{{Name: "curl", Version: "7.88"}},
+		},
+		{
+			name: "multiple_with_version",
+			args: []string{"curl", "wget"},
+			ver:  "1.0",
+			want: []snack.Target{{Name: "curl", Version: "1.0"}, {Name: "wget", Version: "1.0"}},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := targets(tt.args, tt.ver)
+			if len(got) != len(tt.want) {
+				t.Fatalf("targets() returned %d, want %d", len(got), len(tt.want))
+			}
+			for i, g := range got {
+				if g.Name != tt.want[i].Name {
+					t.Errorf("[%d] Name = %q, want %q", i, g.Name, tt.want[i].Name)
+				}
+				if g.Version != tt.want[i].Version {
+					t.Errorf("[%d] Version = %q, want %q", i, g.Version, tt.want[i].Version)
+				}
+			}
+		})
+	}
+}
+
+func TestOpts(t *testing.T) {
+	// Reset flags
+	flagSudo = false
+	flagYes = false
+	flagDry = false
+
+	o := opts()
+	if len(o) != 0 {
+		t.Errorf("expected 0 options with no flags, got %d", len(o))
+	}
+
+	flagSudo = true
+	o = opts()
+	if len(o) != 1 {
+		t.Errorf("expected 1 option with sudo, got %d", len(o))
+	}
+
+	flagYes = true
+	flagDry = true
+	o = opts()
+	if len(o) != 3 {
+		t.Errorf("expected 3 options with all flags, got %d", len(o))
+	}
+
+	// Clean up
+	flagSudo = false
+	flagYes = false
+	flagDry = false
+}
+
+func TestOptsApply(t *testing.T) {
+	flagSudo = true
+	flagYes = true
+	flagDry = true
+	defer func() {
+		flagSudo = false
+		flagYes = false
+		flagDry = false
+	}()
+
+	applied := snack.ApplyOptions(opts()...)
+	if !applied.Sudo {
+		t.Error("expected Sudo=true")
+	}
+	if !applied.AssumeYes {
+		t.Error("expected AssumeYes=true")
+	}
+	if !applied.DryRun {
+		t.Error("expected DryRun=true")
+	}
+}
+
+func TestGetManager(t *testing.T) {
+	// Default detection
+	flagMgr = ""
+	m, err := getManager()
+	if err != nil {
+		t.Skipf("no manager available: %v", err)
+	}
+	if m.Name() == "" {
+		t.Error("expected non-empty manager name")
+	}
+
+	// Explicit override
+	flagMgr = "apt"
+	m, err = getManager()
+	if err != nil {
+		t.Fatalf("getManager() with --manager=apt failed: %v", err)
+	}
+	if m.Name() != "apt" {
+		t.Errorf("expected Name()=apt, got %q", m.Name())
+	}
+
+	// Unknown manager
+	flagMgr = "nonexistent-manager-xyz"
+	_, err = getManager()
+	if err == nil {
+		t.Error("expected error for unknown manager")
+	}
+
+	flagMgr = ""
+}
+
+func TestVersionString(t *testing.T) {
+	if version == "" {
+		t.Error("version should not be empty")
+	}
+}

detect/detect_other.go

@@ -0,0 +1,13 @@
+//go:build !linux && !freebsd && !openbsd
+
+package detect
+
+// candidates returns an empty list on unsupported platforms.
+func candidates() []managerFactory {
+	return nil
+}
+
+// allManagers returns an empty list on unsupported platforms.
+func allManagers() []managerFactory {
+	return nil
+}

detect/detect_test.go

@@ -1,7 +1,10 @@
 package detect
 
 import (
+	"errors"
 	"testing"
+
+	"github.com/gogrlx/snack"
 )
 
 func TestByNameUnknown(t *testing.T) {
@@ -9,15 +12,62 @@ func TestByNameUnknown(t *testing.T) {
 	if err == nil {
 		t.Fatal("expected error for unknown manager")
 	}
+	if !errors.Is(err, snack.ErrManagerNotFound) {
+		t.Errorf("expected ErrManagerNotFound, got %v", err)
+	}
+}
+
+func TestByNameKnown(t *testing.T) {
+	// All known manager names should be resolvable by ByName, even if
+	// unavailable on this system.
+	knownNames := []string{"apt", "dnf", "pacman", "apk", "flatpak", "snap", "aur"}
+	for _, name := range knownNames {
+		t.Run(name, func(t *testing.T) {
+			m, err := ByName(name)
+			if err != nil {
+				t.Fatalf("ByName(%q) returned error: %v", name, err)
+			}
+			if m.Name() != name {
+				t.Errorf("ByName(%q).Name() = %q", name, m.Name())
+			}
+		})
+	}
+}
+
+func TestByNameReturnsCorrectType(t *testing.T) {
+	m, err := ByName("apt")
+	if err != nil {
+		t.Skip("apt not in allManagers on this platform")
+	}
+	if m.Name() != "apt" {
+		t.Errorf("expected Name()=apt, got %q", m.Name())
+	}
 }
 
 func TestAllReturnsSlice(t *testing.T) {
-	// Just verify it doesn't panic; actual availability depends on system.
-	_ = All()
+	managers := All()
+	// On Linux with apt installed, we should get at least 1
+	// But don't fail if none — could be a weird CI environment
+	seen := make(map[string]bool)
+	for _, m := range managers {
+		name := m.Name()
+		if seen[name] {
+			t.Errorf("duplicate manager in All(): %s", name)
+		}
+		seen[name] = true
+	}
+}
+
+func TestAllManagersAreAvailable(t *testing.T) {
+	for _, m := range All() {
+		if !m.Available() {
+			t.Errorf("All() returned unavailable manager: %s", m.Name())
+		}
+	}
 }
 
 func TestDefaultDoesNotPanic(t *testing.T) {
-	// May return error if no managers available; that's fine.
+	Reset()
 	_, _ = Default()
 }
 
@@ -37,9 +87,65 @@ func TestDefaultCachesResult(t *testing.T) {
 	}
 }
 
+func TestDefaultReturnsAvailableManager(t *testing.T) {
+	Reset()
+	m, err := Default()
+	if err != nil {
+		t.Skipf("no manager available on this system: %v", err)
+	}
+	if !m.Available() {
+		t.Error("Default() returned unavailable manager")
+	}
+	if m.Name() == "" {
+		t.Error("Default() returned manager with empty name")
+	}
+}
+
 func TestResetAllowsRedetection(t *testing.T) {
 	_, _ = Default()
 	Reset()
-	// After reset, defaultOnce should be fresh; calling Default() again should work.
+	// After reset, calling Default() again should work.
 	_, _ = Default()
 }
+
+func TestResetConcurrent(t *testing.T) {
+	done := make(chan struct{})
+	for i := 0; i < 10; i++ {
+		go func() {
+			defer func() { done <- struct{}{} }()
+			Reset()
+			_, _ = Default()
+		}()
+	}
+	for i := 0; i < 10; i++ {
+		<-done
+	}
+}
+
+func TestHasBinary(t *testing.T) {
+	// sh should exist on any Unix system
+	if !HasBinary("sh") {
+		t.Error("expected HasBinary(sh) = true")
+	}
+	if HasBinary("this-binary-does-not-exist-anywhere-12345") {
+		t.Error("expected HasBinary(nonexistent) = false")
+	}
+}
+
+func TestCandidatesNotEmpty(t *testing.T) {
+	c := candidates()
+	if len(c) == 0 {
+		t.Error("candidates() returned empty slice")
+	}
+}
+
+func TestAllManagersNotEmpty(t *testing.T) {
+	a := allManagers()
+	if len(a) == 0 {
+		t.Error("allManagers() returned empty slice")
+	}
+	// allManagers should be a superset of candidates
+	if len(a) < len(candidates()) {
+		t.Error("allManagers() should include at least all candidates")
+	}
+}

dnf/dnf_test.go

@@ -0,0 +1,87 @@
+package dnf
+
+import (
+	"testing"
+
+	"github.com/gogrlx/snack"
+)
+
+// Compile-time interface assertions — DNF implements all optional interfaces.
+var (
+	_ snack.Manager        = (*DNF)(nil)
+	_ snack.VersionQuerier = (*DNF)(nil)
+	_ snack.Holder         = (*DNF)(nil)
+	_ snack.Cleaner        = (*DNF)(nil)
+	_ snack.FileOwner      = (*DNF)(nil)
+	_ snack.RepoManager    = (*DNF)(nil)
+	_ snack.KeyManager     = (*DNF)(nil)
+	_ snack.Grouper        = (*DNF)(nil)
+	_ snack.NameNormalizer = (*DNF)(nil)
+	_ snack.DryRunner      = (*DNF)(nil)
+	_ snack.PackageUpgrader = (*DNF)(nil)
+)
+
+func TestName(t *testing.T) {
+	d := New()
+	if got := d.Name(); got != "dnf" {
+		t.Errorf("Name() = %q, want %q", got, "dnf")
+	}
+}
+
+func TestSupportsDryRun(t *testing.T) {
+	d := New()
+	if !d.SupportsDryRun() {
+		t.Error("SupportsDryRun() = false, want true")
+	}
+}
+
+func TestGetCapabilities(t *testing.T) {
+	d := New()
+	caps := snack.GetCapabilities(d)
+
+	tests := []struct {
+		name string
+		got  bool
+	}{
+		{"VersionQuery", caps.VersionQuery},
+		{"Hold", caps.Hold},
+		{"Clean", caps.Clean},
+		{"FileOwnership", caps.FileOwnership},
+		{"RepoManagement", caps.RepoManagement},
+		{"KeyManagement", caps.KeyManagement},
+		{"Groups", caps.Groups},
+		{"NameNormalize", caps.NameNormalize},
+		{"DryRun", caps.DryRun},
+		{"PackageUpgrade", caps.PackageUpgrade},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if !tt.got {
+				t.Errorf("Capabilities.%s = false, want true", tt.name)
+			}
+		})
+	}
+}
+
+func TestNormalizeNameMethod(t *testing.T) {
+	d := New()
+	tests := []struct {
+		input, want string
+	}{
+		{"nginx.x86_64", "nginx"},
+		{"curl", "curl"},
+	}
+	for _, tt := range tests {
+		if got := d.NormalizeName(tt.input); got != tt.want {
+			t.Errorf("NormalizeName(%q) = %q, want %q", tt.input, got, tt.want)
+		}
+	}
+}
+
+func TestParseArchMethod(t *testing.T) {
+	d := New()
+	name, arch := d.ParseArch("nginx.x86_64")
+	if name != "nginx" || arch != "x86_64" {
+		t.Errorf("ParseArch(\"nginx.x86_64\") = (%q, %q), want (\"nginx\", \"x86_64\")", name, arch)
+	}
+}

dnf/parse_test.go

@@ -3,8 +3,6 @@ package dnf
 import (
 	"strings"
 	"testing"
-
-	"github.com/gogrlx/snack"
 )
 
 func TestParseList(t *testing.T) {
@@ -458,15 +456,399 @@ updates-testing                 Fedora 43 - x86_64 - Test Updates
 	}
 }
 
-// Ensure interface checks from capabilities.go are satisfied.
-var (
-	_ snack.Manager        = (*DNF)(nil)
-	_ snack.VersionQuerier = (*DNF)(nil)
-	_ snack.Holder         = (*DNF)(nil)
-	_ snack.Cleaner        = (*DNF)(nil)
-	_ snack.FileOwner      = (*DNF)(nil)
-	_ snack.RepoManager    = (*DNF)(nil)
-	_ snack.KeyManager     = (*DNF)(nil)
-	_ snack.Grouper        = (*DNF)(nil)
-	_ snack.NameNormalizer = (*DNF)(nil)
-)
+// --- Edge case tests ---
+
+func TestParseListEmpty(t *testing.T) {
+	pkgs := parseList("")
+	if len(pkgs) != 0 {
+		t.Errorf("expected 0 packages from empty input, got %d", len(pkgs))
+	}
+}
+
+func TestParseListSinglePackage(t *testing.T) {
+	input := `Installed Packages
+curl.x86_64                     7.76.1-23.el9                  @baseos
+`
+	pkgs := parseList(input)
+	if len(pkgs) != 1 {
+		t.Fatalf("expected 1 package, got %d", len(pkgs))
+	}
+	if pkgs[0].Name != "curl" {
+		t.Errorf("Name = %q, want curl", pkgs[0].Name)
+	}
+}
+
+func TestParseListMalformedLines(t *testing.T) {
+	input := `Installed Packages
+curl.x86_64                     7.76.1-23.el9                  @baseos
+thislinehasnospaces
+   only-one-field
+bash.x86_64                     5.1.8-6.el9                    @anaconda
+`
+	pkgs := parseList(input)
+	if len(pkgs) != 2 {
+		t.Fatalf("expected 2 packages (skip malformed), got %d", len(pkgs))
+	}
+}
+
+func TestParseListNoHeader(t *testing.T) {
+	// Lines that look like packages without the "Installed Packages" header
+	input := `curl.x86_64                     7.76.1-23.el9                  @baseos
+bash.x86_64                     5.1.8-6.el9                    @anaconda
+`
+	pkgs := parseList(input)
+	if len(pkgs) != 2 {
+		t.Fatalf("expected 2 packages, got %d", len(pkgs))
+	}
+}
+
+func TestParseListTwoColumns(t *testing.T) {
+	// Only name.arch and version, no repo column
+	input := `Installed Packages
+curl.x86_64                     7.76.1-23.el9
+`
+	pkgs := parseList(input)
+	if len(pkgs) != 1 {
+		t.Fatalf("expected 1 package, got %d", len(pkgs))
+	}
+	if pkgs[0].Repository != "" {
+		t.Errorf("Repository = %q, want empty", pkgs[0].Repository)
+	}
+}
+
+func TestParseSearchEmpty(t *testing.T) {
+	pkgs := parseSearch("")
+	if len(pkgs) != 0 {
+		t.Errorf("expected 0 packages from empty input, got %d", len(pkgs))
+	}
+}
+
+func TestParseSearchSingleResult(t *testing.T) {
+	input := `=== Name Exactly Matched: curl ===
+curl.x86_64 : A utility for getting files from remote servers
+`
+	pkgs := parseSearch(input)
+	if len(pkgs) != 1 {
+		t.Fatalf("expected 1 package, got %d", len(pkgs))
+	}
+	if pkgs[0].Name != "curl" {
+		t.Errorf("Name = %q, want curl", pkgs[0].Name)
+	}
+}
+
+func TestParseSearchMalformedLines(t *testing.T) {
+	input := `=== Name Matched ===
+curl.x86_64 : A utility
+no-separator-here
+another.line.without : proper : colons
+bash.noarch : Shell
+`
+	pkgs := parseSearch(input)
+	// "curl.x86_64 : A utility" and "another.line.without : proper : colons" and "bash.noarch : Shell"
+	if len(pkgs) != 3 {
+		t.Fatalf("expected 3 packages, got %d", len(pkgs))
+	}
+}
+
+func TestParseInfoEmpty(t *testing.T) {
+	p := parseInfo("")
+	if p != nil {
+		t.Errorf("expected nil from empty input, got %+v", p)
+	}
+}
+
+func TestParseInfoNoName(t *testing.T) {
+	input := `Version      : 1.0
+Architecture : x86_64
+`
+	p := parseInfo(input)
+	if p != nil {
+		t.Errorf("expected nil when no Name field, got %+v", p)
+	}
+}
+
+func TestParseInfoReleaseBeforeVersion(t *testing.T) {
+	// Release without prior Version should not panic
+	input := `Name    : test
+Release : 1.el9
+Version : 2.0
+`
+	p := parseInfo(input)
+	if p == nil {
+		t.Fatal("expected non-nil package")
+	}
+	// Release came before Version was set, so it won't append properly,
+	// but Version should at least be set
+	if p.Name != "test" {
+		t.Errorf("Name = %q, want test", p.Name)
+	}
+}
+
+func TestParseInfoFromRepo(t *testing.T) {
+	input := `Name         : bash
+Version      : 5.1.8
+Release      : 6.el9
+From repo    : baseos
+Summary      : The GNU Bourne Again shell
+`
+	p := parseInfo(input)
+	if p == nil {
+		t.Fatal("expected non-nil package")
+	}
+	if p.Repository != "baseos" {
+		t.Errorf("Repository = %q, want baseos", p.Repository)
+	}
+}
+
+func TestParseVersionLockEmpty(t *testing.T) {
+	pkgs := parseVersionLock("")
+	if len(pkgs) != 0 {
+		t.Errorf("expected 0 packages from empty input, got %d", len(pkgs))
+	}
+}
+
+func TestParseVersionLockSingleEntry(t *testing.T) {
+	input := `nginx-0:1.20.1-14.el9_2.1.*
+`
+	pkgs := parseVersionLock(input)
+	if len(pkgs) != 1 {
+		t.Fatalf("expected 1 package, got %d", len(pkgs))
+	}
+	if pkgs[0].Name != "nginx" {
+		t.Errorf("Name = %q, want nginx", pkgs[0].Name)
+	}
+}
+
+func TestParseRepoListEmpty(t *testing.T) {
+	repos := parseRepoList("")
+	if len(repos) != 0 {
+		t.Errorf("expected 0 repos from empty input, got %d", len(repos))
+	}
+}
+
+func TestParseRepoListSingleRepo(t *testing.T) {
+	input := `repo id                              repo name                                        status
+baseos                               CentOS Stream 9 - BaseOS                         enabled
+`
+	repos := parseRepoList(input)
+	if len(repos) != 1 {
+		t.Fatalf("expected 1 repo, got %d", len(repos))
+	}
+	if repos[0].ID != "baseos" || !repos[0].Enabled {
+		t.Errorf("unexpected repo: %+v", repos[0])
+	}
+}
+
+func TestParseGroupListEmpty(t *testing.T) {
+	groups := parseGroupList("")
+	if len(groups) != 0 {
+		t.Errorf("expected 0 groups from empty input, got %d", len(groups))
+	}
+}
+
+func TestParseGroupInfoEmpty(t *testing.T) {
+	pkgs := parseGroupInfo("")
+	if len(pkgs) != 0 {
+		t.Errorf("expected 0 packages from empty input, got %d", len(pkgs))
+	}
+}
+
+func TestParseGroupInfoWithMarks(t *testing.T) {
+	input := `Group: Web Server
+ Mandatory Packages:
+   = httpd
+   + mod_ssl
+   - php
+`
+	pkgs := parseGroupInfo(input)
+	if len(pkgs) != 3 {
+		t.Fatalf("expected 3 packages, got %d", len(pkgs))
+	}
+	names := map[string]bool{}
+	for _, p := range pkgs {
+		names[p.Name] = true
+	}
+	for _, want := range []string{"httpd", "mod_ssl", "php"} {
+		if !names[want] {
+			t.Errorf("missing package %q", want)
+		}
+	}
+}
+
+func TestParseGroupIsInstalledEmpty(t *testing.T) {
+	if parseGroupIsInstalled("", "anything") {
+		t.Error("expected false for empty input")
+	}
+}
+
+func TestNormalizeNameEdgeCases(t *testing.T) {
+	tests := []struct {
+		input, want string
+	}{
+		{"", ""},
+		{"pkg.unknown.ext", "pkg.unknown.ext"},
+		{"name.with.dots.x86_64", "name.with.dots"},
+		{"python3.11", "python3.11"},
+		{"glibc.s390x", "glibc"},
+		{"kernel.src", "kernel"},
+		{".x86_64", ""},
+		{"pkg.ppc64le", "pkg"},
+		{"pkg.armv7hl", "pkg"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			got := normalizeName(tt.input)
+			if got != tt.want {
+				t.Errorf("normalizeName(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestParseArchEdgeCases(t *testing.T) {
+	tests := []struct {
+		input, wantName, wantArch string
+	}{
+		{"", "", ""},
+		{"pkg.i386", "pkg", "i386"},
+		{"pkg.ppc64le", "pkg", "ppc64le"},
+		{"pkg.s390x", "pkg", "s390x"},
+		{"pkg.armv7hl", "pkg", "armv7hl"},
+		{"pkg.src", "pkg", "src"},
+		{"pkg.unknown", "pkg.unknown", ""},
+		{"name.with.many.dots.noarch", "name.with.many.dots", "noarch"},
+		{".noarch", "", "noarch"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			name, arch := parseArch(tt.input)
+			if name != tt.wantName || arch != tt.wantArch {
+				t.Errorf("parseArch(%q) = (%q, %q), want (%q, %q)",
+					tt.input, name, arch, tt.wantName, tt.wantArch)
+			}
+		})
+	}
+}
+
+// --- dnf5 edge case tests ---
+
+func TestStripPreambleEmpty(t *testing.T) {
+	got := stripPreamble("")
+	if got != "" {
+		t.Errorf("expected empty, got %q", got)
+	}
+}
+
+func TestStripPreambleNoPreamble(t *testing.T) {
+	input := "Installed packages\nbash.x86_64   5.3.0-2.fc43   abc\n"
+	got := stripPreamble(input)
+	if got != input {
+		t.Errorf("expected unchanged output when no preamble present")
+	}
+}
+
+func TestParseListDNF5Empty(t *testing.T) {
+	pkgs := parseListDNF5("")
+	if len(pkgs) != 0 {
+		t.Errorf("expected 0 packages from empty input, got %d", len(pkgs))
+	}
+}
+
+func TestParseListDNF5SinglePackage(t *testing.T) {
+	input := `Installed packages
+curl.aarch64   7.76.1-23.el9   abc123
+`
+	pkgs := parseListDNF5(input)
+	if len(pkgs) != 1 {
+		t.Fatalf("expected 1 package, got %d", len(pkgs))
+	}
+	if pkgs[0].Name != "curl" || pkgs[0].Arch != "aarch64" {
+		t.Errorf("unexpected: %+v", pkgs[0])
+	}
+}
+
+func TestParseSearchDNF5Empty(t *testing.T) {
+	pkgs := parseSearchDNF5("")
+	if len(pkgs) != 0 {
+		t.Errorf("expected 0 packages from empty input, got %d", len(pkgs))
+	}
+}
+
+func TestParseInfoDNF5Empty(t *testing.T) {
+	p := parseInfoDNF5("")
+	if p != nil {
+		t.Errorf("expected nil from empty input, got %+v", p)
+	}
+}
+
+func TestParseInfoDNF5NoName(t *testing.T) {
+	input := `Version : 1.0
+Architecture : x86_64
+`
+	p := parseInfoDNF5(input)
+	if p != nil {
+		t.Errorf("expected nil when no Name field, got %+v", p)
+	}
+}
+
+func TestParseGroupListDNF5Empty(t *testing.T) {
+	groups := parseGroupListDNF5("")
+	if len(groups) != 0 {
+		t.Errorf("expected 0 groups from empty input, got %d", len(groups))
+	}
+}
+
+func TestParseGroupIsInstalledDNF5Empty(t *testing.T) {
+	if parseGroupIsInstalledDNF5("", "anything") {
+		t.Error("expected false for empty input")
+	}
+}
+
+func TestParseVersionLockDNF5Empty(t *testing.T) {
+	pkgs := parseVersionLockDNF5("")
+	if len(pkgs) != 0 {
+		t.Errorf("expected 0 packages from empty input, got %d", len(pkgs))
+	}
+}
+
+func TestParseVersionLockDNF5SingleEntry(t *testing.T) {
+	input := `# Added by 'versionlock add' command on 2026-02-26 03:14:29
+Package name: nginx
+evr = 1.20.1-14.el9
+`
+	pkgs := parseVersionLockDNF5(input)
+	if len(pkgs) != 1 {
+		t.Fatalf("expected 1 package, got %d", len(pkgs))
+	}
+	if pkgs[0].Name != "nginx" {
+		t.Errorf("Name = %q, want nginx", pkgs[0].Name)
+	}
+}
+
+func TestParseRepoListDNF5Empty(t *testing.T) {
+	repos := parseRepoListDNF5("")
+	if len(repos) != 0 {
+		t.Errorf("expected 0 repos from empty input, got %d", len(repos))
+	}
+}
+
+func TestParseGroupInfoDNF5Empty(t *testing.T) {
+	pkgs := parseGroupInfoDNF5("")
+	if len(pkgs) != 0 {
+		t.Errorf("expected 0 packages from empty input, got %d", len(pkgs))
+	}
+}
+
+func TestParseGroupInfoDNF5SinglePackage(t *testing.T) {
+	input := `Id                   : test-group
+Name                 : Test
+Mandatory packages   : single-pkg
+`
+	pkgs := parseGroupInfoDNF5(input)
+	if len(pkgs) != 1 {
+		t.Fatalf("expected 1 package, got %d", len(pkgs))
+	}
+	if pkgs[0].Name != "single-pkg" {
+		t.Errorf("Name = %q, want single-pkg", pkgs[0].Name)
+	}
+}

dpkg/dpkg_test.go

@@ -86,5 +86,145 @@ func TestUpdateUnsupported(t *testing.T) {
 	}
 }
 
-// Verify Dpkg implements snack.Manager at compile time.
-var _ snack.Manager = (*Dpkg)(nil)
+// Compile-time interface assertions.
+var (
+	_ snack.Manager        = (*Dpkg)(nil)
+	_ snack.FileOwner      = (*Dpkg)(nil)
+	_ snack.NameNormalizer = (*Dpkg)(nil)
+	_ snack.DryRunner      = (*Dpkg)(nil)
+)
+
+func TestSupportsDryRun(t *testing.T) {
+	d := New()
+	if !d.SupportsDryRun() {
+		t.Error("expected SupportsDryRun() = true")
+	}
+}
+
+func TestCapabilities(t *testing.T) {
+	caps := snack.GetCapabilities(New())
+	checks := []struct {
+		name string
+		got  bool
+		want bool
+	}{
+		{"FileOwnership", caps.FileOwnership, true},
+		{"NameNormalize", caps.NameNormalize, true},
+		{"DryRun", caps.DryRun, true},
+		{"VersionQuery", caps.VersionQuery, false},
+		{"Hold", caps.Hold, false},
+		{"Clean", caps.Clean, false},
+		{"RepoManagement", caps.RepoManagement, false},
+		{"KeyManagement", caps.KeyManagement, false},
+		{"Groups", caps.Groups, false},
+		{"PackageUpgrade", caps.PackageUpgrade, false},
+	}
+	for _, c := range checks {
+		t.Run(c.name, func(t *testing.T) {
+			if c.got != c.want {
+				t.Errorf("%s = %v, want %v", c.name, c.got, c.want)
+			}
+		})
+	}
+}
+
+func TestNormalizeNameMethod(t *testing.T) {
+	d := New()
+	if got := d.NormalizeName("curl:amd64"); got != "curl" {
+		t.Errorf("NormalizeName(curl:amd64) = %q, want %q", got, "curl")
+	}
+}
+
+func TestParseArchMethod(t *testing.T) {
+	d := New()
+	name, arch := d.ParseArch("bash:arm64")
+	if name != "bash" || arch != "arm64" {
+		t.Errorf("ParseArch(bash:arm64) = (%q, %q), want (bash, arm64)", name, arch)
+	}
+}
+
+func TestParseListEdgeCases(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  int
+	}{
+		{"empty", "", 0},
+		{"whitespace_only", "  \n  \n  ", 0},
+		{"single_installed", "bash\t5.2-1\tinstall ok installed", 1},
+		{"no_status_field", "bash\t5.2-1", 1},
+		{"blank_lines_mixed", "\nbash\t5.2-1\tinstall ok installed\n\ncurl\t7.88\tinstall ok installed\n", 2},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkgs := parseList(tt.input)
+			if len(pkgs) != tt.want {
+				t.Errorf("parseList() returned %d packages, want %d", len(pkgs), tt.want)
+			}
+		})
+	}
+}
+
+func TestParseDpkgListEdgeCases(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  int
+	}{
+		{"empty", "", 0},
+		{"header_only", "Desired=Unknown/Install/Remove/Purge/Hold\n||/ Name Version Architecture Description\n+++-====-====-====-====", 0},
+		{"single_package", "ii  bash  5.2-1  amd64  GNU Bourne Again SHell", 1},
+		{"held_package", "hi  nginx  1.24  amd64  web server", 1},
+		{"purge_pending", "pn  oldpkg  1.0  amd64  old package", 1},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkgs := parseDpkgList(tt.input)
+			if len(pkgs) != tt.want {
+				t.Errorf("parseDpkgList() returned %d packages, want %d", len(pkgs), tt.want)
+			}
+		})
+	}
+}
+
+func TestParseInfoEdgeCases(t *testing.T) {
+	t.Run("no_package_field", func(t *testing.T) {
+		_, err := parseInfo("Version: 1.0\nArchitecture: amd64\n")
+		if err != snack.ErrNotFound {
+			t.Errorf("expected ErrNotFound, got %v", err)
+		}
+	})
+
+	t.Run("all_fields", func(t *testing.T) {
+		input := "Package: vim\nStatus: install ok installed\nVersion: 9.0\nArchitecture: arm64\nDescription: Vi IMproved\n"
+		p, err := parseInfo(input)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if p.Name != "vim" || p.Version != "9.0" || p.Arch != "arm64" || !p.Installed {
+			t.Errorf("unexpected: %+v", p)
+		}
+	})
+
+	t.Run("version_with_epoch", func(t *testing.T) {
+		input := "Package: systemd\nVersion: 1:252-2\n"
+		p, err := parseInfo(input)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if p.Version != "1:252-2" {
+			t.Errorf("Version = %q, want %q", p.Version, "1:252-2")
+		}
+	})
+
+	t.Run("not_installed_status", func(t *testing.T) {
+		input := "Package: curl\nStatus: deinstall ok config-files\nVersion: 7.88\n"
+		p, err := parseInfo(input)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if p.Installed {
+			t.Error("expected Installed=false for deinstall status")
+		}
+	})
+}

dpkg/normalize_test.go

@@ -0,0 +1,74 @@
+package dpkg
+
+import "testing"
+
+func TestNormalizeName(t *testing.T) {
+	tests := []struct {
+		input string
+		want  string
+	}{
+		{"curl", "curl"},
+		{"curl:amd64", "curl"},
+		{"bash:arm64", "bash"},
+		{"python3:i386", "python3"},
+		{"libc6:armhf", "libc6"},
+		{"pkg:armel", "pkg"},
+		{"pkg:mips", "pkg"},
+		{"pkg:mipsel", "pkg"},
+		{"pkg:mips64el", "pkg"},
+		{"pkg:ppc64el", "pkg"},
+		{"pkg:s390x", "pkg"},
+		{"pkg:all", "pkg"},
+		{"pkg:any", "pkg"},
+		// Unknown arch suffix should be kept
+		{"pkg:unknown", "pkg:unknown"},
+		{"libstdc++6:amd64", "libstdc++6"},
+		{"", ""},
+		// Multiple colons — only last one checked
+		{"a:b:amd64", "a:b"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			got := normalizeName(tt.input)
+			if got != tt.want {
+				t.Errorf("normalizeName(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestParseArch(t *testing.T) {
+	tests := []struct {
+		input    string
+		wantName string
+		wantArch string
+	}{
+		{"curl:amd64", "curl", "amd64"},
+		{"bash:arm64", "bash", "arm64"},
+		{"python3", "python3", ""},
+		{"curl:i386", "curl", "i386"},
+		{"pkg:armhf", "pkg", "armhf"},
+		{"pkg:armel", "pkg", "armel"},
+		{"pkg:mips", "pkg", "mips"},
+		{"pkg:mipsel", "pkg", "mipsel"},
+		{"pkg:mips64el", "pkg", "mips64el"},
+		{"pkg:ppc64el", "pkg", "ppc64el"},
+		{"pkg:s390x", "pkg", "s390x"},
+		{"pkg:all", "pkg", "all"},
+		{"pkg:any", "pkg", "any"},
+		// Unknown arch — not split
+		{"pkg:foobar", "pkg:foobar", ""},
+		{"", "", ""},
+		// Multiple colons
+		{"a:b:arm64", "a:b", "arm64"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			name, arch := parseArch(tt.input)
+			if name != tt.wantName || arch != tt.wantArch {
+				t.Errorf("parseArch(%q) = (%q, %q), want (%q, %q)",
+					tt.input, name, arch, tt.wantName, tt.wantArch)
+			}
+		})
+	}
+}

flatpak/flatpak_test.go

@@ -37,6 +37,71 @@ func TestParseListEmpty(t *testing.T) {
 	}
 }
 
+func TestParseListEdgeCases(t *testing.T) {
+	t.Run("single entry", func(t *testing.T) {
+		pkgs := parseList("Firefox\torg.mozilla.Firefox\t131.0\tflathub\n")
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Name != "Firefox" {
+			t.Errorf("expected Firefox, got %q", pkgs[0].Name)
+		}
+	})
+
+	t.Run("two fields only", func(t *testing.T) {
+		pkgs := parseList("Firefox\torg.mozilla.Firefox\n")
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Name != "Firefox" {
+			t.Errorf("expected Firefox, got %q", pkgs[0].Name)
+		}
+		if pkgs[0].Version != "" {
+			t.Errorf("expected empty version, got %q", pkgs[0].Version)
+		}
+		if pkgs[0].Repository != "" {
+			t.Errorf("expected empty repository, got %q", pkgs[0].Repository)
+		}
+	})
+
+	t.Run("single field skipped", func(t *testing.T) {
+		pkgs := parseList("Firefox\n")
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages (needs >=2 fields), got %d", len(pkgs))
+		}
+	})
+
+	t.Run("extra fields", func(t *testing.T) {
+		pkgs := parseList("Firefox\torg.mozilla.Firefox\t131.0\tflathub\textra\n")
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Repository != "flathub" {
+			t.Errorf("expected flathub, got %q", pkgs[0].Repository)
+		}
+	})
+
+	t.Run("whitespace only lines", func(t *testing.T) {
+		pkgs := parseList("   \n\t\n  \n")
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages, got %d", len(pkgs))
+		}
+	})
+
+	t.Run("three fields no repo", func(t *testing.T) {
+		pkgs := parseList("GIMP\torg.gimp.GIMP\t2.10.38\n")
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Version != "2.10.38" {
+			t.Errorf("expected version 2.10.38, got %q", pkgs[0].Version)
+		}
+		if pkgs[0].Repository != "" {
+			t.Errorf("expected empty repository, got %q", pkgs[0].Repository)
+		}
+	})
+}
+
 func TestParseSearch(t *testing.T) {
 	input := "Firefox\torg.mozilla.Firefox\t131.0\tflathub\n" +
 		"Firefox ESR\torg.mozilla.FirefoxESR\t128.3\tflathub\n"
@@ -60,6 +125,32 @@ func TestParseSearchNoMatches(t *testing.T) {
 	}
 }
 
+func TestParseSearchEdgeCases(t *testing.T) {
+	t.Run("empty", func(t *testing.T) {
+		pkgs := parseSearch("")
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages, got %d", len(pkgs))
+		}
+	})
+
+	t.Run("single field line skipped", func(t *testing.T) {
+		pkgs := parseSearch("JustAName\n")
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages (needs >=2 fields), got %d", len(pkgs))
+		}
+	})
+
+	t.Run("not installed result", func(t *testing.T) {
+		pkgs := parseSearch("VLC\torg.videolan.VLC\t3.0.20\tflathub\n")
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Installed {
+			t.Error("search results should not be marked installed")
+		}
+	})
+}
+
 func TestParseInfo(t *testing.T) {
 	input := `Name: Firefox
 Description: Fast, private web browser
@@ -92,6 +183,46 @@ func TestParseInfoEmpty(t *testing.T) {
 	}
 }
 
+func TestParseInfoEdgeCases(t *testing.T) {
+	t.Run("name only", func(t *testing.T) {
+		pkg := parseInfo("Name: VLC\n")
+		if pkg == nil {
+			t.Fatal("expected non-nil")
+		}
+		if pkg.Name != "VLC" {
+			t.Errorf("expected VLC, got %q", pkg.Name)
+		}
+	})
+
+	t.Run("no name returns nil", func(t *testing.T) {
+		pkg := parseInfo("Version: 1.0\nArch: x86_64\n")
+		if pkg != nil {
+			t.Error("expected nil when no Name field")
+		}
+	})
+
+	t.Run("no colon lines ignored", func(t *testing.T) {
+		pkg := parseInfo("Name: Test\nsome random line without colon\nVersion: 2.0\n")
+		if pkg == nil {
+			t.Fatal("expected non-nil")
+		}
+		if pkg.Version != "2.0" {
+			t.Errorf("expected version 2.0, got %q", pkg.Version)
+		}
+	})
+
+	t.Run("value with colons", func(t *testing.T) {
+		pkg := parseInfo("Name: MyApp\nDescription: A tool: does things: well\n")
+		if pkg == nil {
+			t.Fatal("expected non-nil")
+		}
+		// parseInfo uses strings.Index for first colon
+		if pkg.Description != "A tool: does things: well" {
+			t.Errorf("unexpected description: %q", pkg.Description)
+		}
+	})
+}
+
 func TestParseRemotes(t *testing.T) {
 	input := "flathub\thttps://dl.flathub.org/repo/\t\n" +
 		"gnome-nightly\thttps://nightly.gnome.org/repo/\tdisabled\n"
@@ -113,10 +244,165 @@ func TestParseRemotes(t *testing.T) {
 	}
 }
 
+func TestParseRemotesEdgeCases(t *testing.T) {
+	t.Run("empty", func(t *testing.T) {
+		repos := parseRemotes("")
+		if len(repos) != 0 {
+			t.Errorf("expected 0 repos, got %d", len(repos))
+		}
+	})
+
+	t.Run("single enabled remote", func(t *testing.T) {
+		repos := parseRemotes("flathub\thttps://dl.flathub.org/repo/\t\n")
+		if len(repos) != 1 {
+			t.Fatalf("expected 1 repo, got %d", len(repos))
+		}
+		if !repos[0].Enabled {
+			t.Error("expected enabled")
+		}
+		if repos[0].Name != "flathub" {
+			t.Errorf("expected Name=flathub, got %q", repos[0].Name)
+		}
+	})
+
+	t.Run("single disabled remote", func(t *testing.T) {
+		repos := parseRemotes("test-remote\thttps://example.com/\tdisabled\n")
+		if len(repos) != 1 {
+			t.Fatalf("expected 1 repo, got %d", len(repos))
+		}
+		if repos[0].Enabled {
+			t.Error("expected disabled")
+		}
+	})
+
+	t.Run("no URL field", func(t *testing.T) {
+		repos := parseRemotes("myremote\n")
+		if len(repos) != 1 {
+			t.Fatalf("expected 1 repo, got %d", len(repos))
+		}
+		if repos[0].ID != "myremote" {
+			t.Errorf("expected myremote, got %q", repos[0].ID)
+		}
+		if repos[0].URL != "" {
+			t.Errorf("expected empty URL, got %q", repos[0].URL)
+		}
+		if !repos[0].Enabled {
+			t.Error("expected enabled by default")
+		}
+	})
+
+	t.Run("whitespace lines ignored", func(t *testing.T) {
+		repos := parseRemotes("  \n\n  \n")
+		if len(repos) != 0 {
+			t.Errorf("expected 0 repos, got %d", len(repos))
+		}
+	})
+}
+
+func TestSemverCmp(t *testing.T) {
+	tests := []struct {
+		name string
+		a, b string
+		want int
+	}{
+		{"equal", "1.0.0", "1.0.0", 0},
+		{"less major", "1.0.0", "2.0.0", -1},
+		{"greater major", "2.0.0", "1.0.0", 1},
+		{"less minor", "1.2.3", "1.3.0", -1},
+		{"less patch", "1.2.3", "1.2.4", -1},
+		{"multi-digit", "1.10.0", "1.9.0", 1},
+		{"short vs long equal", "1.0", "1.0.0", 0},
+		{"short vs long less", "1.0", "1.0.1", -1},
+		{"short vs long greater", "1.1", "1.0.9", 1},
+		{"single component", "5", "3", 1},
+		{"single equal", "3", "3", 0},
+		{"empty vs empty", "", "", 0},
+		{"empty vs version", "", "1.0", -1},
+		{"version vs empty", "1.0", "", 1},
+		{"non-numeric suffix", "1.0.0-beta", "1.0.0-rc1", 0},
+		{"pre-release stripped", "1.0.0beta2", "1.0.0rc1", 0},
+		{"four components", "1.2.3.4", "1.2.3.5", -1},
+		{"different lengths", "1.0.0.0", "1.0.0", 0},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := semverCmp(tt.a, tt.b)
+			if got != tt.want {
+				t.Errorf("semverCmp(%q, %q) = %d, want %d", tt.a, tt.b, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestStripNonNumeric(t *testing.T) {
+	tests := []struct {
+		input string
+		want  string
+	}{
+		{"123", "123"},
+		{"123abc", "123"},
+		{"abc", ""},
+		{"0beta", "0"},
+		{"", ""},
+		{"42-rc1", "42"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			got := stripNonNumeric(tt.input)
+			if got != tt.want {
+				t.Errorf("stripNonNumeric(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}
+
 func TestInterfaceCompliance(t *testing.T) {
 	var _ snack.Manager = (*Flatpak)(nil)
 	var _ snack.Cleaner = (*Flatpak)(nil)
 	var _ snack.RepoManager = (*Flatpak)(nil)
+	var _ snack.VersionQuerier = (*Flatpak)(nil)
+	var _ snack.PackageUpgrader = (*Flatpak)(nil)
+}
+
+// Compile-time interface checks in test file
+var (
+	_ snack.VersionQuerier  = (*Flatpak)(nil)
+	_ snack.PackageUpgrader = (*Flatpak)(nil)
+)
+
+func TestCapabilities(t *testing.T) {
+	caps := snack.GetCapabilities(New())
+	if !caps.Clean {
+		t.Error("expected Clean=true")
+	}
+	if !caps.RepoManagement {
+		t.Error("expected RepoManagement=true")
+	}
+	if !caps.VersionQuery {
+		t.Error("expected VersionQuery=true")
+	}
+	// Should be false
+	if caps.FileOwnership {
+		t.Error("expected FileOwnership=false")
+	}
+	if caps.DryRun {
+		t.Error("expected DryRun=false")
+	}
+	if caps.Hold {
+		t.Error("expected Hold=false")
+	}
+	if caps.KeyManagement {
+		t.Error("expected KeyManagement=false")
+	}
+	if caps.Groups {
+		t.Error("expected Groups=false")
+	}
+	if caps.NameNormalize {
+		t.Error("expected NameNormalize=false")
+	}
+	if !caps.PackageUpgrade {
+		t.Error("expected PackageUpgrade=true")
+	}
 }
 
 func TestName(t *testing.T) {

go.mod

@@ -27,7 +27,7 @@ require (
 	github.com/charmbracelet/x/windows v0.2.2 // indirect
 	github.com/clipperhouse/displaywidth v0.11.0 // indirect
 	github.com/clipperhouse/uax29/v2 v2.7.0 // indirect
-	github.com/cloudflare/circl v1.6.1 // indirect
+	github.com/cloudflare/circl v1.6.3 // indirect
 	github.com/containerd/errdefs v1.0.0 // indirect
 	github.com/containerd/errdefs/pkg v0.3.0 // indirect
 	github.com/containerd/log v0.1.0 // indirect

go.sum

@@ -43,8 +43,8 @@ github.com/clipperhouse/displaywidth v0.11.0 h1:lBc6kY44VFw+TDx4I8opi/EtL9m20WSE
 github.com/clipperhouse/displaywidth v0.11.0/go.mod h1:bkrFNkf81G8HyVqmKGxsPufD3JhNl3dSqnGhOoSD/o0=
 github.com/clipperhouse/uax29/v2 v2.7.0 h1:+gs4oBZ2gPfVrKPthwbMzWZDaAFPGYK72F0NJv2v7Vk=
 github.com/clipperhouse/uax29/v2 v2.7.0/go.mod h1:EFJ2TJMRUaplDxHKj1qAEhCtQPW2tJSwu5BF98AuoVM=
-github.com/cloudflare/circl v1.6.1 h1:zqIqSPIndyBh1bjLVVDHMPpVKqp8Su/V+6MeDzzQBQ0=
-github.com/cloudflare/circl v1.6.1/go.mod h1:uddAzsPgqdMAYatqJ0lsjX1oECcQLIlRpzZh3pJrofs=
+github.com/cloudflare/circl v1.6.3 h1:9GPOhQGF9MCYUeXyMYlqTR6a5gTrgR/fBLXvUgtVcg8=
+github.com/cloudflare/circl v1.6.3/go.mod h1:2eXP6Qfat4O/Yhh8BznvKnJ+uzEoTQ6jVKJRn81BiS4=
 github.com/containerd/errdefs v1.0.0 h1:tg5yIfIlQIrxYtu9ajqY42W3lpS19XqdxRQeEwYG8PI=
 github.com/containerd/errdefs v1.0.0/go.mod h1:+YBYIdtsnF4Iw6nWZhJcqGSg/dwvV7tyJ/kCkyJ2k+M=
 github.com/containerd/errdefs/pkg v0.3.0 h1:9IKJ06FvyNlexW690DXuQNx2KA2cUJXx151Xdx3ZPPE=

pacman/helpers_test.go

@@ -79,36 +79,88 @@ func TestBuildArgs_RootBeforeBaseArgs(t *testing.T) {
 	assert.Greater(t, sIdx, rIdx, "root flag should come before base args")
 }
 
-func TestParseUpgrades_Empty(t *testing.T) {
-	assert.Empty(t, parseUpgrades(""))
-}
+func TestParseUpgrades(t *testing.T) {
+	tests := []struct {
+		name      string
+		input     string
+		wantLen   int
+		wantNames []string
+		wantVers  []string
+	}{
+		{
+			name:    "empty",
+			input:   "",
+			wantLen: 0,
+		},
+		{
+			name:    "whitespace only",
+			input:   "   \n  \n\n\t\n",
+			wantLen: 0,
+		},
+		{
+			name:      "standard arrow format",
+			input:     "linux 6.7.3.arch1-1 -> 6.7.4.arch1-1\nvim 9.0.2-1 -> 9.1.0-1\n",
+			wantLen:   2,
+			wantNames: []string{"linux", "vim"},
+			wantVers:  []string{"6.7.4.arch1-1", "9.1.0-1"},
+		},
+		{
+			name:      "single package arrow format",
+			input:     "curl 8.6.0-1 -> 8.7.1-1\n",
+			wantLen:   1,
+			wantNames: []string{"curl"},
+			wantVers:  []string{"8.7.1-1"},
+		},
+		{
+			name:      "fallback two-field format",
+			input:     "pkg 2.0\n",
+			wantLen:   1,
+			wantNames: []string{"pkg"},
+			wantVers:  []string{"2.0"},
+		},
+		{
+			name:      "mixed arrow and fallback",
+			input:     "linux 6.7.3 -> 6.7.4\npkg 2.0\n",
+			wantLen:   2,
+			wantNames: []string{"linux", "pkg"},
+			wantVers:  []string{"6.7.4", "2.0"},
+		},
+		{
+			name:      "whitespace around entries",
+			input:     "\n  \nlinux 6.7.3 -> 6.7.4\n\n",
+			wantLen:   1,
+			wantNames: []string{"linux"},
+			wantVers:  []string{"6.7.4"},
+		},
+		{
+			name:    "single field line skipped",
+			input:   "orphan\nvalid 1.0 -> 2.0\n",
+			wantLen: 1,
+		},
+		{
+			name:      "epoch in version",
+			input:     "java-runtime 1:21.0.2-1 -> 1:21.0.3-1\n",
+			wantLen:   1,
+			wantNames: []string{"java-runtime"},
+			wantVers:  []string{"1:21.0.3-1"},
+		},
+	}
 
-func TestParseUpgrades_Standard(t *testing.T) {
-	input := `linux 6.7.3.arch1-1 -> 6.7.4.arch1-1
-vim 9.0.2-1 -> 9.1.0-1
-`
-	pkgs := parseUpgrades(input)
-	require.Len(t, pkgs, 2)
-	assert.Equal(t, "linux", pkgs[0].Name)
-	assert.Equal(t, "6.7.4.arch1-1", pkgs[0].Version)
-	assert.True(t, pkgs[0].Installed)
-	assert.Equal(t, "vim", pkgs[1].Name)
-	assert.Equal(t, "9.1.0-1", pkgs[1].Version)
-}
-
-func TestParseUpgrades_FallbackFormat(t *testing.T) {
-	// Some versions of pacman might output "pkg newver" without the arrow
-	input := "pkg 2.0\n"
-	pkgs := parseUpgrades(input)
-	require.Len(t, pkgs, 1)
-	assert.Equal(t, "pkg", pkgs[0].Name)
-	assert.Equal(t, "2.0", pkgs[0].Version)
-}
-
-func TestParseUpgrades_WhitespaceLines(t *testing.T) {
-	input := "\n  \nlinux 6.7.3 -> 6.7.4\n\n"
-	pkgs := parseUpgrades(input)
-	require.Len(t, pkgs, 1)
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkgs := parseUpgrades(tt.input)
+			require.Len(t, pkgs, tt.wantLen)
+			for i, p := range pkgs {
+				assert.True(t, p.Installed, "all upgrade entries should have Installed=true")
+				if i < len(tt.wantNames) {
+					assert.Equal(t, tt.wantNames[i], p.Name)
+				}
+				if i < len(tt.wantVers) {
+					assert.Equal(t, tt.wantVers[i], p.Version)
+				}
+			}
+		})
+	}
 }
 
 func TestParseGroupPkgSet_Empty(t *testing.T) {
@@ -149,6 +201,31 @@ group pkg2
 	assert.Len(t, set, 2)
 }
 
+func TestParseGroupPkgSet_WhitespaceOnly(t *testing.T) {
+	set := parseGroupPkgSet("   \n  \n\t\n")
+	assert.Empty(t, set)
+}
+
+func TestParseGroupPkgSet_MultipleGroups(t *testing.T) {
+	// Different group names, same package names — set uses pkg name (second field)
+	input := `base-devel gcc
+xorg xorg-server
+base-devel gcc
+`
+	set := parseGroupPkgSet(input)
+	assert.Len(t, set, 2)
+	assert.Contains(t, set, "gcc")
+	assert.Contains(t, set, "xorg-server")
+}
+
+func TestParseGroupPkgSet_ExtraFields(t *testing.T) {
+	// Lines with more than 2 fields — should still use second field
+	input := "group pkg extra stuff\n"
+	set := parseGroupPkgSet(input)
+	assert.Len(t, set, 1)
+	assert.Contains(t, set, "pkg")
+}
+
 func TestNew(t *testing.T) {
 	p := New()
 	assert.NotNil(t, p)

pacman/pacman_test.go

@@ -130,6 +130,59 @@ func TestBuildArgs(t *testing.T) {
 
 func TestInterfaceCompliance(t *testing.T) {
 	var _ snack.Manager = (*Pacman)(nil)
+	var _ snack.VersionQuerier = (*Pacman)(nil)
+	var _ snack.Cleaner = (*Pacman)(nil)
+	var _ snack.FileOwner = (*Pacman)(nil)
+	var _ snack.Grouper = (*Pacman)(nil)
+	var _ snack.DryRunner = (*Pacman)(nil)
+	var _ snack.PackageUpgrader = (*Pacman)(nil)
+}
+
+func TestInterfaceNonCompliance(t *testing.T) {
+	p := New()
+	var m snack.Manager = p
+
+	if _, ok := m.(snack.Holder); ok {
+		t.Error("Pacman should not implement Holder")
+	}
+	if _, ok := m.(snack.RepoManager); ok {
+		t.Error("Pacman should not implement RepoManager")
+	}
+	if _, ok := m.(snack.KeyManager); ok {
+		t.Error("Pacman should not implement KeyManager")
+	}
+	if _, ok := m.(snack.NameNormalizer); ok {
+		t.Error("Pacman should not implement NameNormalizer")
+	}
+}
+
+func TestCapabilities(t *testing.T) {
+	caps := snack.GetCapabilities(New())
+
+	tests := []struct {
+		name string
+		got  bool
+		want bool
+	}{
+		{"VersionQuery", caps.VersionQuery, true},
+		{"Clean", caps.Clean, true},
+		{"FileOwnership", caps.FileOwnership, true},
+		{"Groups", caps.Groups, true},
+		{"DryRun", caps.DryRun, true},
+		{"Hold", caps.Hold, false},
+		{"RepoManagement", caps.RepoManagement, false},
+		{"KeyManagement", caps.KeyManagement, false},
+		{"NameNormalize", caps.NameNormalize, false},
+		{"PackageUpgrade", caps.PackageUpgrade, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.got != tt.want {
+				t.Errorf("%s = %v, want %v", tt.name, tt.got, tt.want)
+			}
+		})
+	}
 }
 
 func TestName(t *testing.T) {

pkg/pkg_test.go

@@ -23,6 +23,94 @@ func TestParseQuery(t *testing.T) {
 	}
 }
 
+func TestParseQueryEdgeCases(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		wantLen  int
+		wantPkgs []snack.Package
+	}{
+		{
+			name:    "empty input",
+			input:   "",
+			wantLen: 0,
+		},
+		{
+			name:    "whitespace only",
+			input:   "   \n  \n\n",
+			wantLen: 0,
+		},
+		{
+			name:    "single entry",
+			input:   "vim\t9.0\tVi IMproved\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "vim", Version: "9.0", Description: "Vi IMproved", Installed: true},
+			},
+		},
+		{
+			name:    "missing description (two fields only)",
+			input:   "bash\t5.2\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "bash", Version: "5.2", Description: "", Installed: true},
+			},
+		},
+		{
+			name:    "single field only (no tabs, skipped)",
+			input:   "justname\n",
+			wantLen: 0,
+		},
+		{
+			name:    "description with tabs",
+			input:   "pkg\t1.0\tA\ttabbed\tdescription\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "pkg", Version: "1.0", Description: "A\ttabbed\tdescription", Installed: true},
+			},
+		},
+		{
+			name:    "trailing and leading whitespace on lines",
+			input:   "  nginx\t1.24.0\tWeb server  \n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "nginx", Version: "1.24.0", Description: "Web server", Installed: true},
+			},
+		},
+		{
+			name:    "multiple entries with blank lines between",
+			input:   "a\t1.0\tAlpha\n\nb\t2.0\tBeta\n",
+			wantLen: 2,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkgs := parseQuery(tt.input)
+			if len(pkgs) != tt.wantLen {
+				t.Fatalf("expected %d packages, got %d", tt.wantLen, len(pkgs))
+			}
+			for i, want := range tt.wantPkgs {
+				if i >= len(pkgs) {
+					break
+				}
+				got := pkgs[i]
+				if got.Name != want.Name {
+					t.Errorf("[%d] Name = %q, want %q", i, got.Name, want.Name)
+				}
+				if got.Version != want.Version {
+					t.Errorf("[%d] Version = %q, want %q", i, got.Version, want.Version)
+				}
+				if got.Description != want.Description {
+					t.Errorf("[%d] Description = %q, want %q", i, got.Description, want.Description)
+				}
+				if got.Installed != want.Installed {
+					t.Errorf("[%d] Installed = %v, want %v", i, got.Installed, want.Installed)
+				}
+			}
+		})
+	}
+}
+
 func TestParseSearch(t *testing.T) {
 	input := `nginx-1.24.0                   Robust and small WWW server
 curl-8.5.0                     Command line tool for transferring data
@@ -39,6 +127,81 @@ curl-8.5.0                     Command line tool for transferring data
 	}
 }
 
+func TestParseSearchEdgeCases(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		wantLen  int
+		wantPkgs []snack.Package
+	}{
+		{
+			name:    "empty input",
+			input:   "",
+			wantLen: 0,
+		},
+		{
+			name:    "name with many hyphens",
+			input:   "py39-django-rest-framework-3.14.0 RESTful Web APIs for Django\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "py39-django-rest-framework", Version: "3.14.0", Description: "RESTful Web APIs for Django"},
+			},
+		},
+		{
+			name:    "no comment (name-version only)",
+			input:   "zsh-5.9\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "zsh", Version: "5.9", Description: ""},
+			},
+		},
+		{
+			name:    "very long output many packages",
+			input:   "a-1.0 desc1\nb-2.0 desc2\nc-3.0 desc3\nd-4.0 desc4\ne-5.0 desc5\n",
+			wantLen: 5,
+		},
+		{
+			name:    "single character name",
+			input:   "R-4.3.2                        Statistical Computing\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "R", Version: "4.3.2", Description: "Statistical Computing"},
+			},
+		},
+		{
+			name:    "version with complex suffix",
+			input:   "libressl-3.8.2_1               TLS library\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "libressl", Version: "3.8.2_1", Description: "TLS library"},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkgs := parseSearch(tt.input)
+			if len(pkgs) != tt.wantLen {
+				t.Fatalf("expected %d packages, got %d", tt.wantLen, len(pkgs))
+			}
+			for i, want := range tt.wantPkgs {
+				if i >= len(pkgs) {
+					break
+				}
+				got := pkgs[i]
+				if got.Name != want.Name {
+					t.Errorf("[%d] Name = %q, want %q", i, got.Name, want.Name)
+				}
+				if got.Version != want.Version {
+					t.Errorf("[%d] Version = %q, want %q", i, got.Version, want.Version)
+				}
+				if got.Description != want.Description {
+					t.Errorf("[%d] Description = %q, want %q", i, got.Description, want.Description)
+				}
+			}
+		})
+	}
+}
+
 func TestParseInfo(t *testing.T) {
 	input := `Name           : nginx
 Version        : 1.24.0
@@ -63,6 +226,77 @@ Arch           : FreeBSD:14:amd64
 	}
 }
 
+func TestParseInfoEdgeCases(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		wantNil bool
+		want    *snack.Package
+	}{
+		{
+			name:    "empty input",
+			input:   "",
+			wantNil: true,
+		},
+		{
+			name:    "no name field returns nil",
+			input:   "Version : 1.0\nComment : test\n",
+			wantNil: true,
+		},
+		{
+			name:  "name only (missing other fields)",
+			input: "Name : bash\n",
+			want:  &snack.Package{Name: "bash", Installed: true},
+		},
+		{
+			name:  "extra unknown fields are ignored",
+			input: "Name : vim\nVersion : 9.0\nMaintainer : someone@example.com\nWWW : https://vim.org\nComment : Vi IMproved\n",
+			want:  &snack.Package{Name: "vim", Version: "9.0", Description: "Vi IMproved", Installed: true},
+		},
+		{
+			name:  "colon in value",
+			input: "Name : nginx\nComment : HTTP server: fast and reliable\n",
+			want:  &snack.Package{Name: "nginx", Description: "HTTP server: fast and reliable", Installed: true},
+		},
+		{
+			name:    "lines without colons are skipped",
+			input:   "This is random text\nNo colons here\n",
+			wantNil: true,
+		},
+		{
+			name:  "whitespace around values",
+			input: "Name           :    curl    \nVersion        :    8.5.0    \n",
+			want:  &snack.Package{Name: "curl", Version: "8.5.0", Installed: true},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := parseInfo(tt.input)
+			if tt.wantNil {
+				if got != nil {
+					t.Errorf("expected nil, got %+v", got)
+				}
+				return
+			}
+			if got == nil {
+				t.Fatal("expected non-nil package")
+			}
+			if got.Name != tt.want.Name {
+				t.Errorf("Name = %q, want %q", got.Name, tt.want.Name)
+			}
+			if got.Version != tt.want.Version {
+				t.Errorf("Version = %q, want %q", got.Version, tt.want.Version)
+			}
+			if got.Description != tt.want.Description {
+				t.Errorf("Description = %q, want %q", got.Description, tt.want.Description)
+			}
+			if got.Installed != tt.want.Installed {
+				t.Errorf("Installed = %v, want %v", got.Installed, tt.want.Installed)
+			}
+		})
+	}
+}
+
 func TestParseUpgrades(t *testing.T) {
 	input := `Updating FreeBSD repository catalogue...
 The following 2 package(s) will be affected:
@@ -84,6 +318,90 @@ Number of packages to be upgraded: 2
 	}
 }
 
+func TestParseUpgradesEdgeCases(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		wantLen  int
+		wantPkgs []snack.Package
+	}{
+		{
+			name:    "empty input",
+			input:   "",
+			wantLen: 0,
+		},
+		{
+			name:    "no upgrade lines",
+			input:   "Updating FreeBSD repository catalogue...\nAll packages are up to date.\n",
+			wantLen: 0,
+		},
+		{
+			name: "mix of Upgrading Installing Reinstalling",
+			input: `Upgrading nginx: 1.24.0 -> 1.26.0
+Installing newpkg: 0 -> 1.0.0
+Reinstalling bash: 5.2 -> 5.2
+`,
+			wantLen: 3,
+			wantPkgs: []snack.Package{
+				{Name: "nginx", Version: "1.26.0", Installed: true},
+				{Name: "newpkg", Version: "1.0.0", Installed: true},
+				{Name: "bash", Version: "5.2", Installed: true},
+			},
+		},
+		{
+			name:    "line with -> but no recognized prefix is skipped",
+			input:   "Something: 1.0 -> 2.0\n",
+			wantLen: 0,
+		},
+		{
+			name:    "upgrading line without colon is skipped",
+			input:   "Upgrading nginx 1.24.0 -> 1.26.0\n",
+			wantLen: 0,
+		},
+		{
+			name:    "upgrading line with -> but not enough parts after colon",
+			input:   "Upgrading nginx: -> \n",
+			wantLen: 0,
+		},
+		{
+			name:    "upgrading line with wrong arrow",
+			input:   "Upgrading nginx: 1.24.0 => 1.26.0\n",
+			wantLen: 0,
+		},
+		{
+			name:  "single upgrade line",
+			input: "Upgrading zsh: 5.8 -> 5.9\n",
+			wantPkgs: []snack.Package{
+				{Name: "zsh", Version: "5.9", Installed: true},
+			},
+			wantLen: 1,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkgs := parseUpgrades(tt.input)
+			if len(pkgs) != tt.wantLen {
+				t.Fatalf("expected %d packages, got %d", tt.wantLen, len(pkgs))
+			}
+			for i, want := range tt.wantPkgs {
+				if i >= len(pkgs) {
+					break
+				}
+				got := pkgs[i]
+				if got.Name != want.Name {
+					t.Errorf("[%d] Name = %q, want %q", i, got.Name, want.Name)
+				}
+				if got.Version != want.Version {
+					t.Errorf("[%d] Version = %q, want %q", i, got.Version, want.Version)
+				}
+				if got.Installed != want.Installed {
+					t.Errorf("[%d] Installed = %v, want %v", i, got.Installed, want.Installed)
+				}
+			}
+		})
+	}
+}
+
 func TestParseFileList(t *testing.T) {
 	input := `nginx-1.24.0:
 	/usr/local/sbin/nginx
@@ -99,6 +417,67 @@ func TestParseFileList(t *testing.T) {
 	}
 }
 
+func TestParseFileListEdgeCases(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		wantLen int
+		want    []string
+	}{
+		{
+			name:    "empty input",
+			input:   "",
+			wantLen: 0,
+		},
+		{
+			name:    "header only no files",
+			input:   "nginx-1.24.0:\n",
+			wantLen: 0,
+		},
+		{
+			name:    "paths with spaces",
+			input:   "pkg-1.0:\n\t/usr/local/share/my package/file name.txt\n\t/usr/local/share/another dir/test\n",
+			wantLen: 2,
+			want: []string{
+				"/usr/local/share/my package/file name.txt",
+				"/usr/local/share/another dir/test",
+			},
+		},
+		{
+			name:    "single file",
+			input:   "bash-5.2:\n\t/usr/local/bin/bash\n",
+			wantLen: 1,
+			want:    []string{"/usr/local/bin/bash"},
+		},
+		{
+			name:    "no header just file paths",
+			input:   "/usr/local/bin/curl\n/usr/local/lib/libcurl.so\n",
+			wantLen: 2,
+		},
+		{
+			name:    "blank lines between files",
+			input:   "pkg-1.0:\n\t/usr/local/bin/a\n\n\t/usr/local/bin/b\n",
+			wantLen: 2,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			files := parseFileList(tt.input)
+			if len(files) != tt.wantLen {
+				t.Fatalf("expected %d files, got %d", tt.wantLen, len(files))
+			}
+			for i, w := range tt.want {
+				if i >= len(files) {
+					break
+				}
+				if files[i] != w {
+					t.Errorf("[%d] got %q, want %q", i, files[i], w)
+				}
+			}
+		})
+	}
+}
+
 func TestParseOwner(t *testing.T) {
 	input := "/usr/local/sbin/nginx was installed by package nginx-1.24.0\n"
 	name := parseOwner(input)
@@ -107,6 +486,48 @@ func TestParseOwner(t *testing.T) {
 	}
 }
 
+func TestParseOwnerEdgeCases(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{
+			name:  "empty input",
+			input: "",
+			want:  "",
+		},
+		{
+			name:  "standard format",
+			input: "/usr/local/bin/curl was installed by package curl-8.5.0\n",
+			want:  "curl",
+		},
+		{
+			name:  "package name with hyphens",
+			input: "/usr/local/lib/libpython3.so was installed by package py39-python-3.9.18\n",
+			want:  "py39-python",
+		},
+		{
+			name:  "no match returns trimmed input",
+			input: "some random output\n",
+			want:  "some random output",
+		},
+		{
+			name:  "whitespace around",
+			input: "  /usr/local/bin/bash was installed by package bash-5.2.21  \n",
+			want:  "bash",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := parseOwner(tt.input)
+			if got != tt.want {
+				t.Errorf("parseOwner(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}
+
 func TestSplitNameVersion(t *testing.T) {
 	tests := []struct {
 		input       string
@@ -126,6 +547,73 @@ func TestSplitNameVersion(t *testing.T) {
 	}
 }
 
+func TestSplitNameVersionEdgeCases(t *testing.T) {
+	tests := []struct {
+		name        string
+		input       string
+		wantName    string
+		wantVersion string
+	}{
+		{
+			name:        "empty string",
+			input:       "",
+			wantName:    "",
+			wantVersion: "",
+		},
+		{
+			name:        "no hyphen",
+			input:       "singleword",
+			wantName:    "singleword",
+			wantVersion: "",
+		},
+		{
+			name:        "multiple hyphens",
+			input:       "py39-django-rest-3.14.0",
+			wantName:    "py39-django-rest",
+			wantVersion: "3.14.0",
+		},
+		{
+			name:        "leading hyphen",
+			input:       "-1.0",
+			wantName:    "-1.0",
+			wantVersion: "",
+		},
+		{
+			name:        "trailing hyphen",
+			input:       "nginx-",
+			wantName:    "nginx",
+			wantVersion: "",
+		},
+		{
+			name:        "only hyphen",
+			input:       "-",
+			wantName:    "-",
+			wantVersion: "",
+		},
+		{
+			name:        "hyphen at index 1",
+			input:       "a-1.0",
+			wantName:    "a",
+			wantVersion: "1.0",
+		},
+		{
+			name:        "version with underscore suffix",
+			input:       "libressl-3.8.2_1",
+			wantName:    "libressl",
+			wantVersion: "3.8.2_1",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			name, ver := splitNameVersion(tt.input)
+			if name != tt.wantName || ver != tt.wantVersion {
+				t.Errorf("splitNameVersion(%q) = (%q, %q), want (%q, %q)",
+					tt.input, name, ver, tt.wantName, tt.wantVersion)
+			}
+		})
+	}
+}
+
 func TestInterfaceCompliance(t *testing.T) {
 	var _ snack.Manager = (*Pkg)(nil)
 	var _ snack.VersionQuerier = (*Pkg)(nil)
@@ -133,9 +621,51 @@ func TestInterfaceCompliance(t *testing.T) {
 	var _ snack.FileOwner = (*Pkg)(nil)
 }
 
+func TestPackageUpgraderInterface(t *testing.T) {
+	var _ snack.PackageUpgrader = (*Pkg)(nil)
+}
+
 func TestName(t *testing.T) {
 	p := New()
 	if p.Name() != "pkg" {
 		t.Errorf("Name() = %q, want %q", p.Name(), "pkg")
 	}
 }
+
+func TestCapabilities(t *testing.T) {
+	caps := snack.GetCapabilities(New())
+
+	// Should be true
+	if !caps.VersionQuery {
+		t.Error("expected VersionQuery=true")
+	}
+	if !caps.Clean {
+		t.Error("expected Clean=true")
+	}
+	if !caps.FileOwnership {
+		t.Error("expected FileOwnership=true")
+	}
+
+	// Should be false
+	if caps.Hold {
+		t.Error("expected Hold=false")
+	}
+	if caps.RepoManagement {
+		t.Error("expected RepoManagement=false")
+	}
+	if caps.KeyManagement {
+		t.Error("expected KeyManagement=false")
+	}
+	if caps.Groups {
+		t.Error("expected Groups=false")
+	}
+	if caps.NameNormalize {
+		t.Error("expected NameNormalize=false")
+	}
+	if caps.DryRun {
+		t.Error("expected DryRun=false")
+	}
+	if !caps.PackageUpgrade {
+		t.Error("expected PackageUpgrade=true")
+	}
+}

ports/ports_test.go

@@ -29,6 +29,93 @@ python-3.11.7p0    interpreted object-oriented programming language
 	}
 }
 
+func TestParseListEdgeCases(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		wantLen  int
+		wantPkgs []snack.Package
+	}{
+		{
+			name:    "empty input",
+			input:   "",
+			wantLen: 0,
+		},
+		{
+			name:    "whitespace only",
+			input:   "   \n  \n\n",
+			wantLen: 0,
+		},
+		{
+			name:    "single entry",
+			input:   "vim-9.0.2100 Vi IMproved\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "vim", Version: "9.0.2100", Description: "Vi IMproved", Installed: true},
+			},
+		},
+		{
+			name:    "no description",
+			input:   "vim-9.0.2100\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "vim", Version: "9.0.2100", Description: "", Installed: true},
+			},
+		},
+		{
+			name:    "empty lines between entries",
+			input:   "bash-5.2 Shell\n\n\ncurl-8.5.0 Transfer tool\n",
+			wantLen: 2,
+			wantPkgs: []snack.Package{
+				{Name: "bash", Version: "5.2", Description: "Shell", Installed: true},
+				{Name: "curl", Version: "8.5.0", Description: "Transfer tool", Installed: true},
+			},
+		},
+		{
+			name:    "package with p-suffix version (OpenBSD style)",
+			input:   "python-3.11.7p0    interpreted language\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "python", Version: "3.11.7p0", Description: "interpreted language", Installed: true},
+			},
+		},
+		{
+			name:    "package name with multiple hyphens",
+			input:   "py3-django-rest-3.14.0 REST framework\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "py3-django-rest", Version: "3.14.0", Description: "REST framework", Installed: true},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkgs := parseList(tt.input)
+			if len(pkgs) != tt.wantLen {
+				t.Fatalf("expected %d packages, got %d", tt.wantLen, len(pkgs))
+			}
+			for i, want := range tt.wantPkgs {
+				if i >= len(pkgs) {
+					break
+				}
+				got := pkgs[i]
+				if got.Name != want.Name {
+					t.Errorf("[%d] Name = %q, want %q", i, got.Name, want.Name)
+				}
+				if got.Version != want.Version {
+					t.Errorf("[%d] Version = %q, want %q", i, got.Version, want.Version)
+				}
+				if got.Description != want.Description {
+					t.Errorf("[%d] Description = %q, want %q", i, got.Description, want.Description)
+				}
+				if got.Installed != want.Installed {
+					t.Errorf("[%d] Installed = %v, want %v", i, got.Installed, want.Installed)
+				}
+			}
+		})
+	}
+}
+
 func TestParseSearchResults(t *testing.T) {
 	input := `nginx-1.24.0
 nginx-1.25.3
@@ -42,6 +129,83 @@ nginx-1.25.3
 	}
 }
 
+func TestParseSearchResultsEdgeCases(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		wantLen  int
+		wantPkgs []snack.Package
+	}{
+		{
+			name:    "empty input",
+			input:   "",
+			wantLen: 0,
+		},
+		{
+			name:    "whitespace only",
+			input:   "  \n\n  \n",
+			wantLen: 0,
+		},
+		{
+			name:    "single result",
+			input:   "curl-8.5.0\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "curl", Version: "8.5.0"},
+			},
+		},
+		{
+			name:    "name with many hyphens",
+			input:   "py3-django-rest-framework-3.14.0\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "py3-django-rest-framework", Version: "3.14.0"},
+			},
+		},
+		{
+			name:    "no version (no hyphen)",
+			input:   "quirks\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "quirks", Version: ""},
+			},
+		},
+		{
+			name:    "p-suffix version",
+			input:   "python-3.11.7p0\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "python", Version: "3.11.7p0"},
+			},
+		},
+		{
+			name:    "multiple results with blank lines",
+			input:   "a-1.0\n\nb-2.0\n\nc-3.0\n",
+			wantLen: 3,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkgs := parseSearchResults(tt.input)
+			if len(pkgs) != tt.wantLen {
+				t.Fatalf("expected %d packages, got %d", tt.wantLen, len(pkgs))
+			}
+			for i, want := range tt.wantPkgs {
+				if i >= len(pkgs) {
+					break
+				}
+				got := pkgs[i]
+				if got.Name != want.Name {
+					t.Errorf("[%d] Name = %q, want %q", i, got.Name, want.Name)
+				}
+				if got.Version != want.Version {
+					t.Errorf("[%d] Version = %q, want %q", i, got.Version, want.Version)
+				}
+			}
+		})
+	}
+}
+
 func TestParseInfoOutput(t *testing.T) {
 	input := `Information for nginx-1.24.0:
 
@@ -82,6 +246,131 @@ curl is a tool to transfer data from or to a server.
 	}
 }
 
+func TestParseInfoOutputEdgeCases(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		pkgArg  string
+		wantNil bool
+		want    *snack.Package
+	}{
+		{
+			name:    "empty input and empty pkg arg",
+			input:   "",
+			pkgArg:  "",
+			wantNil: true,
+		},
+		{
+			name:   "empty input with pkg arg fallback",
+			input:  "",
+			pkgArg: "curl-8.5.0",
+			want:   &snack.Package{Name: "curl", Version: "8.5.0", Installed: true},
+		},
+		{
+			name:   "no header, falls back to pkg arg",
+			input:  "Some random output\nwithout the expected header",
+			pkgArg: "vim-9.0",
+			want:   &snack.Package{Name: "vim", Version: "9.0", Installed: true},
+		},
+		{
+			name: "comment on same line as Comment: label",
+			input: `Information for zsh-5.9:
+
+Comment: Zsh shell
+`,
+			pkgArg: "zsh-5.9",
+			want:   &snack.Package{Name: "zsh", Version: "5.9", Description: "Zsh shell", Installed: true},
+		},
+		{
+			name: "comment on next line after Comment: label (not captured as description)",
+			input: `Information for bash-5.2:
+
+Comment:
+GNU Bourne Again Shell
+`,
+			pkgArg: "bash-5.2",
+			// Comment: with nothing after the colon sets Description="",
+			// and the next line isn't in a Description: block so it's ignored.
+			want: &snack.Package{Name: "bash", Version: "5.2", Description: "", Installed: true},
+		},
+		{
+			name: "description spans multiple lines",
+			input: `Information for git-2.43.0:
+
+Comment: distributed version control system
+Description:
+Git is a fast, scalable, distributed revision control system
+with an unusually rich command set.
+`,
+			pkgArg: "git-2.43.0",
+			want:   &snack.Package{Name: "git", Version: "2.43.0", Description: "distributed version control system", Installed: true},
+		},
+		{
+			name: "extra fields are ignored",
+			input: `Information for tmux-3.3a:
+
+Comment: terminal multiplexer
+Maintainer: someone@openbsd.org
+WWW: https://tmux.github.io
+Description:
+tmux is a terminal multiplexer.
+`,
+			pkgArg: "tmux-3.3a",
+			want:   &snack.Package{Name: "tmux", Version: "3.3a", Description: "terminal multiplexer", Installed: true},
+		},
+		{
+			name:   "pkg arg with no version (no hyphen)",
+			input:  "",
+			pkgArg: "quirks",
+			want:   &snack.Package{Name: "quirks", Version: "", Installed: true},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := parseInfoOutput(tt.input, tt.pkgArg)
+			if tt.wantNil {
+				if got != nil {
+					t.Errorf("expected nil, got %+v", got)
+				}
+				return
+			}
+			if got == nil {
+				t.Fatal("expected non-nil package")
+			}
+			if got.Name != tt.want.Name {
+				t.Errorf("Name = %q, want %q", got.Name, tt.want.Name)
+			}
+			if got.Version != tt.want.Version {
+				t.Errorf("Version = %q, want %q", got.Version, tt.want.Version)
+			}
+			if tt.want.Description != "" && got.Description != tt.want.Description {
+				t.Errorf("Description = %q, want %q", got.Description, tt.want.Description)
+			}
+			if got.Installed != tt.want.Installed {
+				t.Errorf("Installed = %v, want %v", got.Installed, tt.want.Installed)
+			}
+		})
+	}
+}
+
+func TestParseInfoOutputEmpty(t *testing.T) {
+	pkg := parseInfoOutput("", "")
+	if pkg != nil {
+		t.Error("expected nil for empty input and empty pkg name")
+	}
+}
+
+func TestParseInfoOutputFallbackToPkgArg(t *testing.T) {
+	input := "Some random output\nwithout the expected header"
+	pkg := parseInfoOutput(input, "curl-8.5.0")
+	if pkg == nil {
+		t.Fatal("expected non-nil package from fallback")
+	}
+	if pkg.Name != "curl" || pkg.Version != "8.5.0" {
+		t.Errorf("unexpected fallback parse: %+v", pkg)
+	}
+}
+
 func TestSplitNameVersion(t *testing.T) {
 	tests := []struct {
 		input       string
@@ -101,57 +390,76 @@ func TestSplitNameVersion(t *testing.T) {
 	}
 }
 
-func TestParseListEmpty(t *testing.T) {
-	pkgs := parseList("")
-	if len(pkgs) != 0 {
-		t.Fatalf("expected 0 packages, got %d", len(pkgs))
+func TestSplitNameVersionEdgeCases(t *testing.T) {
+	tests := []struct {
+		name        string
+		input       string
+		wantName    string
+		wantVersion string
+	}{
+		{
+			name:        "empty string",
+			input:       "",
+			wantName:    "",
+			wantVersion: "",
+		},
+		{
+			name:        "no hyphen",
+			input:       "singleword",
+			wantName:    "singleword",
+			wantVersion: "",
+		},
+		{
+			name:        "multiple hyphens",
+			input:       "py3-django-rest-3.14.0",
+			wantName:    "py3-django-rest",
+			wantVersion: "3.14.0",
+		},
+		{
+			name:        "leading hyphen (idx=0, returns whole string)",
+			input:       "-1.0",
+			wantName:    "-1.0",
+			wantVersion: "",
+		},
+		{
+			name:        "trailing hyphen",
+			input:       "nginx-",
+			wantName:    "nginx",
+			wantVersion: "",
+		},
+		{
+			name:        "only hyphen",
+			input:       "-",
+			wantName:    "-",
+			wantVersion: "",
+		},
+		{
+			name:        "hyphen at index 1",
+			input:       "a-1.0",
+			wantName:    "a",
+			wantVersion: "1.0",
+		},
+		{
+			name:        "p-suffix version",
+			input:       "python-3.11.7p0",
+			wantName:    "python",
+			wantVersion: "3.11.7p0",
+		},
+		{
+			name:        "version with v prefix",
+			input:       "go-v1.21.5",
+			wantName:    "go",
+			wantVersion: "v1.21.5",
+		},
 	}
-}
-
-func TestParseListWhitespaceOnly(t *testing.T) {
-	pkgs := parseList("   \n  \n\n")
-	if len(pkgs) != 0 {
-		t.Fatalf("expected 0 packages, got %d", len(pkgs))
-	}
-}
-
-func TestParseListNoDescription(t *testing.T) {
-	input := "vim-9.0.2100\n"
-	pkgs := parseList(input)
-	if len(pkgs) != 1 {
-		t.Fatalf("expected 1 package, got %d", len(pkgs))
-	}
-	if pkgs[0].Name != "vim" || pkgs[0].Version != "9.0.2100" {
-		t.Errorf("unexpected package: %+v", pkgs[0])
-	}
-	if pkgs[0].Description != "" {
-		t.Errorf("expected empty description, got %q", pkgs[0].Description)
-	}
-}
-
-func TestParseSearchResultsEmpty(t *testing.T) {
-	pkgs := parseSearchResults("")
-	if len(pkgs) != 0 {
-		t.Fatalf("expected 0 packages, got %d", len(pkgs))
-	}
-}
-
-func TestParseInfoOutputEmpty(t *testing.T) {
-	pkg := parseInfoOutput("", "")
-	if pkg != nil {
-		t.Error("expected nil for empty input and empty pkg name")
-	}
-}
-
-func TestParseInfoOutputFallbackToPkgArg(t *testing.T) {
-	// No "Information for" header — should fall back to parsing the pkg argument.
-	input := "Some random output\nwithout the expected header"
-	pkg := parseInfoOutput(input, "curl-8.5.0")
-	if pkg == nil {
-		t.Fatal("expected non-nil package from fallback")
-	}
-	if pkg.Name != "curl" || pkg.Version != "8.5.0" {
-		t.Errorf("unexpected fallback parse: %+v", pkg)
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			name, ver := splitNameVersion(tt.input)
+			if name != tt.wantName || ver != tt.wantVersion {
+				t.Errorf("splitNameVersion(%q) = (%q, %q), want (%q, %q)",
+					tt.input, name, ver, tt.wantName, tt.wantVersion)
+			}
+		})
 	}
 }
 
@@ -163,14 +471,7 @@ func TestSplitNameVersionNoHyphen(t *testing.T) {
 }
 
 func TestSplitNameVersionLeadingHyphen(t *testing.T) {
-	// A hyphen at position 0 should return the whole string as name.
 	name, ver := splitNameVersion("-1.0")
-	if name != "" || ver != "1.0" {
-		// LastIndex("-1.0", "-") is 0, and idx <= 0 returns (s, "")
-		// Actually idx=0 means the condition idx <= 0 is true
-	}
-	// Re-check: idx=0, condition is idx <= 0, so returns (s, "")
-	name, ver = splitNameVersion("-1.0")
 	if name != "-1.0" || ver != "" {
 		t.Errorf("splitNameVersion(\"-1.0\") = (%q, %q), want (\"-1.0\", \"\")", name, ver)
 	}
@@ -196,6 +497,91 @@ python-3.11.7p0 -> python-3.11.8p0
 	}
 }
 
+func TestParseUpgradeOutputEdgeCases(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		wantLen  int
+		wantPkgs []snack.Package
+	}{
+		{
+			name:    "empty input",
+			input:   "",
+			wantLen: 0,
+		},
+		{
+			name:    "whitespace only",
+			input:   "  \n\n  \n",
+			wantLen: 0,
+		},
+		{
+			name:    "single upgrade",
+			input:   "bash-5.2 -> bash-5.3\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "bash", Version: "5.3", Installed: true},
+			},
+		},
+		{
+			name:    "line without -> is skipped",
+			input:   "Some info line\nbash-5.2 -> bash-5.3\nAnother line\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "bash", Version: "5.3", Installed: true},
+			},
+		},
+		{
+			name:    "malformed line (-> but not enough fields)",
+			input:   "-> bash-5.3\n",
+			wantLen: 0,
+		},
+		{
+			name:    "wrong arrow (=> instead of ->)",
+			input:   "bash-5.2 => bash-5.3\n",
+			wantLen: 0,
+		},
+		{
+			name:    "package name with multiple hyphens",
+			input:   "py3-django-rest-3.14.0 -> py3-django-rest-3.15.0\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "py3-django-rest", Version: "3.15.0", Installed: true},
+			},
+		},
+		{
+			name:    "p-suffix versions",
+			input:   "python-3.11.7p0 -> python-3.11.8p1\n",
+			wantLen: 1,
+			wantPkgs: []snack.Package{
+				{Name: "python", Version: "3.11.8p1", Installed: true},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pkgs := parseUpgradeOutput(tt.input)
+			if len(pkgs) != tt.wantLen {
+				t.Fatalf("expected %d packages, got %d", tt.wantLen, len(pkgs))
+			}
+			for i, want := range tt.wantPkgs {
+				if i >= len(pkgs) {
+					break
+				}
+				got := pkgs[i]
+				if got.Name != want.Name {
+					t.Errorf("[%d] Name = %q, want %q", i, got.Name, want.Name)
+				}
+				if got.Version != want.Version {
+					t.Errorf("[%d] Version = %q, want %q", i, got.Version, want.Version)
+				}
+				if got.Installed != want.Installed {
+					t.Errorf("[%d] Installed = %v, want %v", i, got.Installed, want.Installed)
+				}
+			}
+		})
+	}
+}
+
 func TestParseUpgradeOutputEmpty(t *testing.T) {
 	pkgs := parseUpgradeOutput("")
 	if len(pkgs) != 0 {
@@ -221,6 +607,73 @@ Files:
 	}
 }
 
+func TestParseFileListOutputEdgeCases(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		wantLen int
+		want    []string
+	}{
+		{
+			name:    "empty input",
+			input:   "",
+			wantLen: 0,
+		},
+		{
+			name:    "header only no files",
+			input:   "Information for pkg-1.0:\n\nFiles:\n",
+			wantLen: 0,
+		},
+		{
+			name:    "paths with spaces",
+			input:   "Information for pkg-1.0:\n\nFiles:\n/usr/local/share/my dir/file name.txt\n/usr/local/share/another path/test\n",
+			wantLen: 2,
+			want: []string{
+				"/usr/local/share/my dir/file name.txt",
+				"/usr/local/share/another path/test",
+			},
+		},
+		{
+			name:    "single file",
+			input:   "Files:\n/usr/local/bin/bash\n",
+			wantLen: 1,
+			want:    []string{"/usr/local/bin/bash"},
+		},
+		{
+			name:    "no header just paths",
+			input:   "/usr/local/bin/a\n/usr/local/bin/b\n",
+			wantLen: 2,
+		},
+		{
+			name:    "blank lines between files",
+			input:   "Files:\n/usr/local/bin/a\n\n/usr/local/bin/b\n",
+			wantLen: 2,
+		},
+		{
+			name:    "non-path lines are skipped",
+			input:   "Information for pkg-1.0:\n\nFiles:\nNot a path\n/usr/local/bin/real\n",
+			wantLen: 1,
+			want:    []string{"/usr/local/bin/real"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			files := parseFileListOutput(tt.input)
+			if len(files) != tt.wantLen {
+				t.Fatalf("expected %d files, got %d", tt.wantLen, len(files))
+			}
+			for i, w := range tt.want {
+				if i >= len(files) {
+					break
+				}
+				if files[i] != w {
+					t.Errorf("[%d] got %q, want %q", i, files[i], w)
+				}
+			}
+		})
+	}
+}
+
 func TestParseFileListOutputEmpty(t *testing.T) {
 	files := parseFileListOutput("")
 	if len(files) != 0 {
@@ -245,6 +698,58 @@ func TestParseOwnerOutput(t *testing.T) {
 	}
 }
 
+func TestParseOwnerOutputEdgeCases(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{
+			name:  "empty input",
+			input: "",
+			want:  "",
+		},
+		{
+			name:  "whitespace only",
+			input: "   \n  ",
+			want:  "",
+		},
+		{
+			name:  "name with many hyphens",
+			input: "py3-django-rest-framework-3.14.0",
+			want:  "py3-django-rest-framework",
+		},
+		{
+			name:  "no version (no hyphen)",
+			input: "quirks",
+			want:  "quirks",
+		},
+		{
+			name:  "leading/trailing whitespace",
+			input: "  curl-8.5.0  ",
+			want:  "curl",
+		},
+		{
+			name:  "p-suffix version",
+			input: "python-3.11.7p0",
+			want:  "python",
+		},
+		{
+			name:  "trailing newline",
+			input: "bash-5.2\n",
+			want:  "bash",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := parseOwnerOutput(tt.input)
+			if got != tt.want {
+				t.Errorf("parseOwnerOutput(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}
+
 func TestInterfaceCompliance(t *testing.T) {
 	var _ snack.Manager = (*Ports)(nil)
 	var _ snack.VersionQuerier = (*Ports)(nil)
@@ -253,9 +758,51 @@ func TestInterfaceCompliance(t *testing.T) {
 	var _ snack.PackageUpgrader = (*Ports)(nil)
 }
 
+func TestPackageUpgraderInterface(t *testing.T) {
+	var _ snack.PackageUpgrader = (*Ports)(nil)
+}
+
 func TestName(t *testing.T) {
 	p := New()
 	if p.Name() != "ports" {
 		t.Errorf("Name() = %q, want %q", p.Name(), "ports")
 	}
 }
+
+func TestCapabilities(t *testing.T) {
+	caps := snack.GetCapabilities(New())
+
+	// Should be true
+	if !caps.VersionQuery {
+		t.Error("expected VersionQuery=true")
+	}
+	if !caps.Clean {
+		t.Error("expected Clean=true")
+	}
+	if !caps.FileOwnership {
+		t.Error("expected FileOwnership=true")
+	}
+
+	// Should be false
+	if caps.Hold {
+		t.Error("expected Hold=false")
+	}
+	if caps.RepoManagement {
+		t.Error("expected RepoManagement=false")
+	}
+	if caps.KeyManagement {
+		t.Error("expected KeyManagement=false")
+	}
+	if caps.Groups {
+		t.Error("expected Groups=false")
+	}
+	if caps.NameNormalize {
+		t.Error("expected NameNormalize=false")
+	}
+	if caps.DryRun {
+		t.Error("expected DryRun=false")
+	}
+	if !caps.PackageUpgrade {
+		t.Error("expected PackageUpgrade=true")
+	}
+}

rpm/parse_test.go

@@ -2,8 +2,6 @@ package rpm
 
 import (
 	"testing"
-
-	"github.com/gogrlx/snack"
 )
 
 func TestParseList(t *testing.T) {
@@ -95,9 +93,128 @@ func TestParseArchSuffix(t *testing.T) {
 	}
 }
 
-// Compile-time interface checks.
-var (
-	_ snack.Manager        = (*RPM)(nil)
-	_ snack.FileOwner      = (*RPM)(nil)
-	_ snack.NameNormalizer = (*RPM)(nil)
-)
+// --- Edge case tests ---
+
+func TestParseListEmpty(t *testing.T) {
+	pkgs := parseList("")
+	if len(pkgs) != 0 {
+		t.Errorf("expected 0 packages from empty input, got %d", len(pkgs))
+	}
+}
+
+func TestParseListSinglePackage(t *testing.T) {
+	input := "curl\t7.76.1-23.el9\tA utility\n"
+	pkgs := parseList(input)
+	if len(pkgs) != 1 {
+		t.Fatalf("expected 1 package, got %d", len(pkgs))
+	}
+	if pkgs[0].Name != "curl" {
+		t.Errorf("Name = %q, want curl", pkgs[0].Name)
+	}
+}
+
+func TestParseListNoDescription(t *testing.T) {
+	input := "bash\t5.1.8-6.el9\n"
+	pkgs := parseList(input)
+	if len(pkgs) != 1 {
+		t.Fatalf("expected 1 package, got %d", len(pkgs))
+	}
+	if pkgs[0].Description != "" {
+		t.Errorf("Description = %q, want empty", pkgs[0].Description)
+	}
+}
+
+func TestParseListMalformedLines(t *testing.T) {
+	input := "bash\t5.1.8-6.el9\tShell\nno-tab-here\ncurl\t7.76.1\tHTTP tool\n"
+	pkgs := parseList(input)
+	if len(pkgs) != 2 {
+		t.Fatalf("expected 2 packages (skip malformed), got %d", len(pkgs))
+	}
+}
+
+func TestParseInfoEmpty(t *testing.T) {
+	p := parseInfo("")
+	if p != nil {
+		t.Errorf("expected nil from empty input, got %+v", p)
+	}
+}
+
+func TestParseInfoNoName(t *testing.T) {
+	input := `Version     : 1.0
+Architecture: x86_64
+`
+	p := parseInfo(input)
+	if p != nil {
+		t.Errorf("expected nil when no Name field, got %+v", p)
+	}
+}
+
+func TestParseInfoArchField(t *testing.T) {
+	// Test both "Architecture" and "Arch" key forms
+	input := `Name        : test
+Version     : 1.0
+Release     : 1.el9
+Arch        : aarch64
+Summary     : Test package
+`
+	p := parseInfo(input)
+	if p == nil {
+		t.Fatal("expected non-nil package")
+	}
+	if p.Arch != "aarch64" {
+		t.Errorf("Arch = %q, want aarch64", p.Arch)
+	}
+}
+
+func TestNormalizeNameEdgeCases(t *testing.T) {
+	tests := []struct {
+		input, want string
+	}{
+		{"", ""},
+		{"pkg.unknown.ext", "pkg.unknown.ext"},
+		{"name.with.dots.x86_64", "name.with.dots"},
+		{"python3.11", "python3.11"},
+		{"glibc.s390x", "glibc"},
+		{"kernel.src", "kernel"},
+		{".x86_64", ""},
+		{"pkg.ppc64le", "pkg"},
+		{"pkg.armv7hl", "pkg"},
+		{"pkg.i386", "pkg"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			got := normalizeName(tt.input)
+			if got != tt.want {
+				t.Errorf("normalizeName(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestParseArchSuffixEdgeCases(t *testing.T) {
+	tests := []struct {
+		input, wantName, wantArch string
+	}{
+		{"", "", ""},
+		{"pkg.i386", "pkg", "i386"},
+		{"pkg.ppc64le", "pkg", "ppc64le"},
+		{"pkg.s390x", "pkg", "s390x"},
+		{"pkg.armv7hl", "pkg", "armv7hl"},
+		{"pkg.src", "pkg", "src"},
+		{"pkg.aarch64", "pkg", "aarch64"},
+		{"pkg.noarch", "pkg", "noarch"},
+		{"pkg.unknown", "pkg.unknown", ""},
+		{"name.with.many.dots.noarch", "name.with.many.dots", "noarch"},
+		{".noarch", "", "noarch"},
+		{"pkg.x86_64.extra", "pkg.x86_64.extra", ""},
+	}
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			name, arch := parseArchSuffix(tt.input)
+			if name != tt.wantName || arch != tt.wantArch {
+				t.Errorf("parseArchSuffix(%q) = (%q, %q), want (%q, %q)",
+					tt.input, name, arch, tt.wantName, tt.wantArch)
+			}
+		})
+	}
+}

rpm/rpm_test.go

@@ -0,0 +1,88 @@
+package rpm
+
+import (
+	"testing"
+
+	"github.com/gogrlx/snack"
+)
+
+// Compile-time interface assertions.
+var (
+	_ snack.Manager        = (*RPM)(nil)
+	_ snack.FileOwner      = (*RPM)(nil)
+	_ snack.NameNormalizer = (*RPM)(nil)
+)
+
+func TestName(t *testing.T) {
+	r := New()
+	if got := r.Name(); got != "rpm" {
+		t.Errorf("Name() = %q, want %q", got, "rpm")
+	}
+}
+
+func TestGetCapabilities(t *testing.T) {
+	r := New()
+	caps := snack.GetCapabilities(r)
+
+	wantTrue := map[string]bool{
+		"FileOwnership": caps.FileOwnership,
+		"NameNormalize": caps.NameNormalize,
+	}
+	for name, got := range wantTrue {
+		t.Run(name+"_true", func(t *testing.T) {
+			if !got {
+				t.Errorf("Capabilities.%s = false, want true", name)
+			}
+		})
+	}
+
+	wantFalse := map[string]bool{
+		"VersionQuery":   caps.VersionQuery,
+		"Hold":           caps.Hold,
+		"Clean":          caps.Clean,
+		"RepoManagement": caps.RepoManagement,
+		"KeyManagement":  caps.KeyManagement,
+		"Groups":         caps.Groups,
+		"DryRun":         caps.DryRun,
+		"PackageUpgrade": caps.PackageUpgrade,
+	}
+	for name, got := range wantFalse {
+		t.Run(name+"_false", func(t *testing.T) {
+			if got {
+				t.Errorf("Capabilities.%s = true, want false", name)
+			}
+		})
+	}
+}
+
+func TestNormalizeNameMethod(t *testing.T) {
+	r := New()
+	tests := []struct {
+		input, want string
+	}{
+		{"nginx.x86_64", "nginx"},
+		{"curl", "curl"},
+		{"bash.noarch", "bash"},
+	}
+	for _, tt := range tests {
+		if got := r.NormalizeName(tt.input); got != tt.want {
+			t.Errorf("NormalizeName(%q) = %q, want %q", tt.input, got, tt.want)
+		}
+	}
+}
+
+func TestParseArchMethod(t *testing.T) {
+	r := New()
+	name, arch := r.ParseArch("nginx.x86_64")
+	if name != "nginx" || arch != "x86_64" {
+		t.Errorf("ParseArch(\"nginx.x86_64\") = (%q, %q), want (\"nginx\", \"x86_64\")", name, arch)
+	}
+}
+
+// RPM should NOT implement DryRunner.
+func TestNotDryRunner(t *testing.T) {
+	r := New()
+	if _, ok := interface{}(r).(snack.DryRunner); ok {
+		t.Error("RPM should not implement DryRunner")
+	}
+}

snap/snap_test.go

@@ -35,6 +35,56 @@ func TestParseSnapListEmpty(t *testing.T) {
 	}
 }
 
+func TestParseSnapListEdgeCases(t *testing.T) {
+	t.Run("single entry", func(t *testing.T) {
+		input := `Name      Version    Rev    Tracking       Publisher   Notes
+core22    20240111   1122   latest/stable  canonical✓  base
+`
+		pkgs := parseSnapList(input)
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Name != "core22" {
+			t.Errorf("expected core22, got %q", pkgs[0].Name)
+		}
+	})
+
+	t.Run("header only no trailing newline", func(t *testing.T) {
+		input := "Name  Version  Rev  Tracking  Publisher  Notes"
+		pkgs := parseSnapList(input)
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages, got %d", len(pkgs))
+		}
+	})
+
+	t.Run("single field line skipped", func(t *testing.T) {
+		input := "Name  Version  Rev  Tracking  Publisher  Notes\nsinglefield\n"
+		pkgs := parseSnapList(input)
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages (need >=2 fields), got %d", len(pkgs))
+		}
+	})
+
+	t.Run("extra whitespace lines", func(t *testing.T) {
+		input := "Name  Version  Rev  Tracking  Publisher  Notes\n  \n\n"
+		pkgs := parseSnapList(input)
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages, got %d", len(pkgs))
+		}
+	})
+
+	t.Run("many columns", func(t *testing.T) {
+		input := "Name  Version  Rev  Tracking  Publisher  Notes\nsnap1  2.0  100  latest/stable  pub  note  extra  more\n"
+		pkgs := parseSnapList(input)
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Name != "snap1" || pkgs[0].Version != "2.0" {
+			t.Errorf("unexpected package: %+v", pkgs[0])
+		}
+	})
+}
+
 func TestParseSnapFind(t *testing.T) {
 	input := `Name      Version   Publisher    Notes  Summary
 firefox   131.0     mozilla✓     -      Mozilla Firefox web browser
@@ -52,6 +102,67 @@ chromium  129.0     nickvdp      -      Chromium web browser
 	}
 }
 
+func TestParseSnapFindEdgeCases(t *testing.T) {
+	t.Run("single result", func(t *testing.T) {
+		input := "Name  Version  Publisher  Notes  Summary\nfirefox  131.0  mozilla  -  Web browser\n"
+		pkgs := parseSnapFind(input)
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Name != "firefox" {
+			t.Errorf("expected firefox, got %q", pkgs[0].Name)
+		}
+		if pkgs[0].Description != "Web browser" {
+			t.Errorf("expected 'Web browser', got %q", pkgs[0].Description)
+		}
+	})
+
+	t.Run("header only", func(t *testing.T) {
+		input := "Name  Version  Publisher  Notes  Summary\n"
+		pkgs := parseSnapFind(input)
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages, got %d", len(pkgs))
+		}
+	})
+
+	t.Run("too few fields skipped", func(t *testing.T) {
+		input := "Name  Version  Publisher  Notes  Summary\nfoo  1.0  pub\n"
+		pkgs := parseSnapFind(input)
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages (need >=4 fields), got %d", len(pkgs))
+		}
+	})
+
+	t.Run("exactly four fields no summary", func(t *testing.T) {
+		input := "Name  Version  Publisher  Notes  Summary\nfoo  1.0  pub  note\n"
+		pkgs := parseSnapFind(input)
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Description != "" {
+			t.Errorf("expected empty description, got %q", pkgs[0].Description)
+		}
+	})
+
+	t.Run("multi-word summary", func(t *testing.T) {
+		input := "Name  Version  Publisher  Notes  Summary\nmysnap  2.0  me  -  A very long description with many words\n"
+		pkgs := parseSnapFind(input)
+		if len(pkgs) != 1 {
+			t.Fatalf("expected 1 package, got %d", len(pkgs))
+		}
+		if pkgs[0].Description != "A very long description with many words" {
+			t.Errorf("unexpected description: %q", pkgs[0].Description)
+		}
+	})
+
+	t.Run("empty input", func(t *testing.T) {
+		pkgs := parseSnapFind("")
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages, got %d", len(pkgs))
+		}
+	})
+}
+
 func TestParseSnapInfo(t *testing.T) {
 	input := `name:      firefox
 summary:   Mozilla Firefox web browser
@@ -84,6 +195,57 @@ func TestParseSnapInfoEmpty(t *testing.T) {
 	}
 }
 
+func TestParseSnapInfoEdgeCases(t *testing.T) {
+	t.Run("not installed snap", func(t *testing.T) {
+		input := `name:      hello-world
+summary:   A simple hello world snap
+publisher: Canonical✓ (canonical✓)
+snap-id:   buPKUD3TKqCOgLEjjHx5kSiCpIs5cMuQ
+`
+		pkg := parseSnapInfo(input)
+		if pkg == nil {
+			t.Fatal("expected non-nil")
+		}
+		if pkg.Name != "hello-world" {
+			t.Errorf("expected hello-world, got %q", pkg.Name)
+		}
+		if pkg.Installed {
+			t.Error("expected Installed=false for snap without installed field")
+		}
+		if pkg.Version != "" {
+			t.Errorf("expected empty version, got %q", pkg.Version)
+		}
+	})
+
+	t.Run("name only", func(t *testing.T) {
+		pkg := parseSnapInfo("name: test\n")
+		if pkg == nil {
+			t.Fatal("expected non-nil")
+		}
+		if pkg.Name != "test" {
+			t.Errorf("expected test, got %q", pkg.Name)
+		}
+	})
+
+	t.Run("no name returns nil", func(t *testing.T) {
+		pkg := parseSnapInfo("summary: something\ninstalled: 1.0 (1) 10MB\n")
+		if pkg != nil {
+			t.Error("expected nil when no name field")
+		}
+	})
+
+	t.Run("no colon lines ignored", func(t *testing.T) {
+		input := "name: mysnap\nrandom text without colon\nsummary: A snap\n"
+		pkg := parseSnapInfo(input)
+		if pkg == nil {
+			t.Fatal("expected non-nil")
+		}
+		if pkg.Description != "A snap" {
+			t.Errorf("unexpected description: %q", pkg.Description)
+		}
+	})
+}
+
 func TestParseSnapInfoVersion(t *testing.T) {
 	input := `name:      firefox
 channels:
@@ -105,6 +267,39 @@ func TestParseSnapInfoVersionMissing(t *testing.T) {
 	}
 }
 
+func TestParseSnapInfoVersionEdgeCases(t *testing.T) {
+	t.Run("empty input", func(t *testing.T) {
+		ver := parseSnapInfoVersion("")
+		if ver != "" {
+			t.Errorf("expected empty, got %q", ver)
+		}
+	})
+
+	t.Run("stable channel with dashes", func(t *testing.T) {
+		input := "  latest/stable:    2024.01.15    2024-01-15 (100) 50MB -\n"
+		ver := parseSnapInfoVersion(input)
+		if ver != "2024.01.15" {
+			t.Errorf("expected 2024.01.15, got %q", ver)
+		}
+	})
+
+	t.Run("closed channel marked --", func(t *testing.T) {
+		input := "  latest/stable:    --\n"
+		ver := parseSnapInfoVersion(input)
+		if ver != "" {
+			t.Errorf("expected empty for closed channel, got %q", ver)
+		}
+	})
+
+	t.Run("closed channel marked ^", func(t *testing.T) {
+		input := "  latest/stable:    ^    \n"
+		ver := parseSnapInfoVersion(input)
+		if ver != "" {
+			t.Errorf("expected empty for ^ channel, got %q", ver)
+		}
+	})
+}
+
 func TestParseSnapRefreshList(t *testing.T) {
 	input := `Name      Version   Rev   Publisher    Notes
 firefox   132.0     4650  mozilla✓     -
@@ -128,30 +323,130 @@ All snaps up to date.
 	}
 }
 
+func TestParseSnapRefreshListEdgeCases(t *testing.T) {
+	t.Run("multiple upgrades", func(t *testing.T) {
+		input := "Name  Version  Rev  Publisher  Notes\nfoo  2.0  10  pub  -\nbar  3.0  20  pub  -\n"
+		pkgs := parseSnapRefreshList(input)
+		if len(pkgs) != 2 {
+			t.Fatalf("expected 2 packages, got %d", len(pkgs))
+		}
+		if pkgs[0].Name != "foo" || pkgs[1].Name != "bar" {
+			t.Errorf("unexpected packages: %+v, %+v", pkgs[0], pkgs[1])
+		}
+	})
+
+	t.Run("header only", func(t *testing.T) {
+		input := "Name  Version  Rev  Publisher  Notes\n"
+		pkgs := parseSnapRefreshList(input)
+		if len(pkgs) != 0 {
+			t.Errorf("expected 0 packages, got %d", len(pkgs))
+		}
+	})
+}
+
 func TestSemverCmp(t *testing.T) {
 	tests := []struct {
+		name string
 		a, b string
 		want int
 	}{
-		{"1.0.0", "1.0.0", 0},
-		{"1.0.0", "2.0.0", -1},
-		{"2.0.0", "1.0.0", 1},
-		{"1.2.3", "1.2.4", -1},
-		{"1.10.0", "1.9.0", 1},
-		{"1.0", "1.0.0", 0},
-		{"131.0", "132.0", -1},
+		{"equal", "1.0.0", "1.0.0", 0},
+		{"less major", "1.0.0", "2.0.0", -1},
+		{"greater major", "2.0.0", "1.0.0", 1},
+		{"less patch", "1.2.3", "1.2.4", -1},
+		{"multi-digit minor", "1.10.0", "1.9.0", 1},
+		{"short vs long equal", "1.0", "1.0.0", 0},
+		{"real versions", "131.0", "132.0", -1},
+		// Edge cases
+		{"single component", "5", "3", 1},
+		{"single equal", "3", "3", 0},
+		{"empty vs empty", "", "", 0},
+		{"empty vs version", "", "1.0", -1},
+		{"version vs empty", "1.0", "", 1},
+		{"non-numeric suffix", "1.0.0-beta", "1.0.0-rc1", 0},
+		{"four components", "1.2.3.4", "1.2.3.5", -1},
+		{"different lengths padded", "1.0.0.0", "1.0.0", 0},
+		{"short less", "1.0", "1.0.1", -1},
+		{"short greater", "1.1", "1.0.9", 1},
 	}
 	for _, tt := range tests {
-		got := semverCmp(tt.a, tt.b)
-		if got != tt.want {
-			t.Errorf("semverCmp(%q, %q) = %d, want %d", tt.a, tt.b, got, tt.want)
-		}
+		t.Run(tt.name, func(t *testing.T) {
+			got := semverCmp(tt.a, tt.b)
+			if got != tt.want {
+				t.Errorf("semverCmp(%q, %q) = %d, want %d", tt.a, tt.b, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestStripNonNumeric(t *testing.T) {
+	tests := []struct {
+		input string
+		want  string
+	}{
+		{"123", "123"},
+		{"123abc", "123"},
+		{"abc", ""},
+		{"0beta", "0"},
+		{"", ""},
+		{"42-rc1", "42"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			got := stripNonNumeric(tt.input)
+			if got != tt.want {
+				t.Errorf("stripNonNumeric(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
 	}
 }
 
 func TestInterfaceCompliance(t *testing.T) {
 	var _ snack.Manager = (*Snap)(nil)
 	var _ snack.VersionQuerier = (*Snap)(nil)
+	var _ snack.Cleaner = (*Snap)(nil)
+	var _ snack.PackageUpgrader = (*Snap)(nil)
+}
+
+// Compile-time interface checks
+var (
+	_ snack.Cleaner         = (*Snap)(nil)
+	_ snack.PackageUpgrader = (*Snap)(nil)
+)
+
+func TestCapabilities(t *testing.T) {
+	caps := snack.GetCapabilities(New())
+	if !caps.VersionQuery {
+		t.Error("expected VersionQuery=true")
+	}
+	if !caps.Clean {
+		t.Error("expected Clean=true")
+	}
+	// Should be false
+	if caps.FileOwnership {
+		t.Error("expected FileOwnership=false")
+	}
+	if caps.DryRun {
+		t.Error("expected DryRun=false")
+	}
+	if caps.Hold {
+		t.Error("expected Hold=false")
+	}
+	if caps.RepoManagement {
+		t.Error("expected RepoManagement=false")
+	}
+	if caps.KeyManagement {
+		t.Error("expected KeyManagement=false")
+	}
+	if caps.Groups {
+		t.Error("expected Groups=false")
+	}
+	if caps.NameNormalize {
+		t.Error("expected NameNormalize=false")
+	}
+	if !caps.PackageUpgrade {
+		t.Error("expected PackageUpgrade=true")
+	}
 }
 
 func TestName(t *testing.T) {