test: exhaustive integration tests with codecov

- Root package unit tests: Targets, TargetNames, ApplyOptions, error sentinels
- Every provider integration test now covers:
  - All Manager interface methods (positive + negative cases)
  - GetCapabilities verification (assert expected interfaces)
  - VersionQuerier: LatestVersion, ListUpgrades, UpgradeAvailable, VersionCmp
  - Holder: Hold, ListHeld, Unhold (apt, dnf)
  - Cleaner: Autoremove, Clean
  - FileOwner: FileList, Owner (+ not-found cases)
  - RepoManager: ListRepos (apt, dnf, flatpak)
  - KeyManager: ListKeys (apt, dnf)
  - Grouper: GroupList, GroupInfo (pacman, dnf)
  - NameNormalizer: NormalizeName, ParseArch table tests (apt, dpkg, dnf, rpm)
- Containertest matrix: 5 distros (debian, alpine, arch, fedora39, fedora-latest)
- CI: coverage profiles uploaded per-job, merged in codecov job
- Added .gitignore for coverage files

detect/detect_integration_test.go

@@ -12,18 +12,53 @@ import (
 )
 
 func TestIntegration_Detect(t *testing.T) {
-	mgr, err := detect.Default()
-	require.NoError(t, err)
-	require.NotNil(t, mgr)
-	t.Logf("Detected: %s", mgr.Name())
+	t.Run("Default", func(t *testing.T) {
+		mgr, err := detect.Default()
+		require.NoError(t, err)
+		require.NotNil(t, mgr)
+		assert.NotEmpty(t, mgr.Name())
+		assert.True(t, mgr.Available())
+		t.Logf("Detected default: %s", mgr.Name())
+	})
 
-	all := detect.All()
-	require.NotEmpty(t, all)
-	for _, m := range all {
-		t.Logf("Available: %s", m.Name())
-	}
+	t.Run("All", func(t *testing.T) {
+		all := detect.All()
+		require.NotEmpty(t, all)
+		for _, m := range all {
+			assert.NotEmpty(t, m.Name())
+			assert.True(t, m.Available())
+			t.Logf("Available: %s", m.Name())
+		}
+	})
 
-	caps := snack.GetCapabilities(mgr)
-	t.Logf("Capabilities: %+v", caps)
-	assert.NotEmpty(t, mgr.Name())
+	t.Run("ByName_Valid", func(t *testing.T) {
+		all := detect.All()
+		require.NotEmpty(t, all)
+
+		// Should be able to find each detected manager by name
+		for _, m := range all {
+			found, err := detect.ByName(m.Name())
+			require.NoError(t, err, "ByName(%s)", m.Name())
+			require.NotNil(t, found)
+			assert.Equal(t, m.Name(), found.Name())
+		}
+	})
+
+	t.Run("ByName_Invalid", func(t *testing.T) {
+		_, err := detect.ByName("xyznonexistentmanager999")
+		assert.Error(t, err)
+		assert.ErrorIs(t, err, snack.ErrManagerNotFound)
+	})
+
+	t.Run("Capabilities", func(t *testing.T) {
+		mgr, err := detect.Default()
+		require.NoError(t, err)
+
+		caps := snack.GetCapabilities(mgr)
+		t.Logf("Default manager %s capabilities: %+v", mgr.Name(), caps)
+
+		// Every manager should have at least the base Manager interface
+		// (which isn't in Capabilities, but let's verify some basics)
+		assert.NotEmpty(t, mgr.Name())
+	})
 }