Add 740 total tests (up from ~200) covering:
- Compile-time interface compliance for all providers
- GetCapabilities assertions for every provider
- Parse function edge cases: empty, malformed, single-entry, multi-entry
- apt: extract inline parse logic into testable functions (parsePolicyCandidate,
parseUpgradeSimulation, parseHoldList, parseOwner, parseSourcesLine)
- dnf/rpm: edge cases for both dnf4 and dnf5 parsers, normalize/parseArch
- pacman/aur: parseUpgrades, parseGroupPkgSet, capabilities
- apk: parseUpgradeSimulation, parseListLine, SupportsDryRun
- flatpak/snap: semverCmp, stripNonNumeric edge cases
- pkg/ports: all parse functions with thorough edge cases
Every provider now has:
- Interface compliance checks (what it implements AND what it doesn't)
- Capabilities test via snack.GetCapabilities()
- Parse function unit tests with table-driven edge cases
Implements the dnf sub-package with Manager, VersionQuerier, Holder,
Cleaner, FileOwner, RepoManager, KeyManager, Grouper, and NameNormalizer
interfaces.
Implements the rpm sub-package with Manager, FileOwner, and
NameNormalizer interfaces.
Both follow the existing pattern: exported methods on struct delegate to
unexported functions, _linux.go for real implementations, _other.go with
build-tag stubs, embedded snack.Locker for mutating operations, and
compile-time interface checks.
Includes parser tests for all output formats.
