Add comprehensive unit tests for lib package with 92.6% coverage

[Claude]

Adds comprehensive unit tests for the lib package achieving 92.6% code coverage using only Go standard library packages.

Test Coverage

• 139 test functions across 10 new test files
• 92.6% statement coverage across all lib files
• 100% coverage for: converter.go, instance.go, lib.go, error.go
• 91-95% coverage for: common.go, config.go, container.go, entry.go

Files Added

• error_test.go - Error type validation and distinctness
• lib_test.go - Constants, types, helper functions
• common_test.go - HTTP utilities, GetIgnoreIPType, WantedListExtended unmarshaling
• entry_test.go - IP prefix operations, marshaling (70+ test cases)
• container_test.go - Container operations, Add/Remove/Lookup with various options (60+ test cases)
• converter_test.go - Converter registration and listing
• config_test.go - Config creators and JSON unmarshaling
• instance_test.go - Instance lifecycle, pipeline operations
• coverage_test.go + coverage2_test.go - Edge cases and error paths

Key Test Scenarios

• IPv4/IPv6 prefix handling including IPv4-mapped IPv6 addresses
• Comment line processing in prefix data (#, //, /*)
• Container operations with IgnoreIPv4/IgnoreIPv6 options
• Entry removal with CaseRemovePrefix and CaseRemoveEntry
• Config parsing with JSON comments and trailing commas (hujson format)
• HTTP fetching for both local files and remote URLs
• Marshal operations (Prefix, IPRange, Text) with filtering options
• Lookup operations with and without search lists
• All 11 error types and error paths

Example Test Coverage

// Tests valid IPv4/IPv6 CIDRs, invalid formats, and comment handling
func TestEntry_AddPrefix_String(t *testing.T) {
    tests := []struct {
        name    string
        prefix  string
        wantErr bool
        errType error
    }{
        {"valid IPv4 CIDR", "192.168.1.0/24", false, nil},
        {"valid IPv6 CIDR", "2001:db8::/32", false, nil},
        {"IP with comment", "192.168.1.0/24 # comment", false, nil},
        {"invalid CIDR", "192.168.1.0/33", true, ErrInvalidCIDR},
    }
    // ... test implementation
}

All tests use only Go standard library - no third-party testing frameworks or dependencies.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• invalid-url-that-does-not-exist-12345.com
  • Triggering command: /tmp/go-build224442873/b001/lib.test /tmp/go-build224442873/b001/lib.test -test.testlogfile=/tmp/go-build224442873/b001/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true 122539/b124/_pkg_.a cfg de/node/bin/git /tmp/ccuxnvzZ.s GOAMD64_v1 l/linux_amd64/co--abbrev-ref ctor ter-�� pkg/mod/golang.org/toolchain@v0.0.1-go1.25.0.linux-amd64/src/net--gdwarf-5 JoXp/88rT0vpzG1WI2T1jJoXp pkg/mod/golang.org/toolchain@v0.0.1-go1.25.0.linux-amd64/pkg/tool/linux_amd64/vet --gdwarf-5 --64 l/linux_amd64/compile tf "%s%s", sep, $0; sep=RS } (dns block)
  • Triggering command: /tmp/go-build992090071/b001/lib.test /tmp/go-build992090071/b001/lib.test -test.testlogfile=/tmp/go-build992090071/b001/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true celain --ignore-submodules | head -n 10 t uname -c -I /tmp/go-build368--abbrev-ref /home/REDACTED/go/HEAD -o /tmp/go-build368122539/b168/_pkg_.a -trimpath de/node/bin/git -p vendor/golang.or-d l/linux_amd64/vet /home/REDACTED/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.0.linHEAD (dns block)
  • Triggering command: /tmp/go-build882738504/b001/lib.test /tmp/go-build882738504/b001/lib.test -test.testlogfile=/tmp/go-build882738504/b001/testlog.txt -test.paniconexit0 -test.timeout=10m0s -uns�� #versions/iojs/#; s#^/home/REDACTED/.nvm/##; \#^[^v]# d; \#^vedirname /tmp/go-build368122539/b002/vet.cfg 0.1-go1.25.0.linux-amd64/bin/go /tmp/go-build368base64 -dumpbase l/linux_amd64/vet git rev-�� --abbrev-ref HEAD /usr/local/bin/git /g git 0.1-go1.25.0.lin--64 git (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)