package guards

import (
	"strings"
	"testing"
)

// testOnlyPackages are the helper packages that import testing from a
// non-test file. Each one's doc comment already says so — "this package
// must never be imported from non-test code: doing so would drag the
// testing package into the production binary" — but a comment is not a
// guard.
//
// It is a slice rather than a single constant because there are now two:
// gate 9's logtest and gate 1's sealtest. A guard that covers one of two
// identical hazards is the shape of bug this repo keeps finding.
var testOnlyPackages = []string{
	"amadan.net/oficina/home/internal/home/logtest",
	"amadan.net/oficina/home/internal/home/sealtest",
}

// TestTestOnlyPackagesNotImportedByProductionCode fails on any
// non-_test.go file that imports one of them, or anything under it: a
// future subpackage must inherit the rule rather than fall outside it on
// an exact match.
//
// An earlier version of this comment said the import registers test
// flags on the default flag set. It does not: since Go 1.13 those are
// registered by testing.Init, which only the generated test main calls.
// The true claim is narrower and is the one Sheets' original makes —
// linking testing into a deployed binary is binary hygiene we do not
// want to argue about per-release, and nothing announces it at build
// time.
func TestTestOnlyPackagesNotImportedByProductionCode(t *testing.T) {
	root := repoRoot(t)
	for _, path := range goFiles(t, root) {
		if strings.HasSuffix(path, "_test.go") {
			continue
		}
		rel := relPath(t, root, path)
		for _, imp := range fileImports(t, path) {
			for _, want := range testOnlyPackages {
				if imp == want || strings.HasPrefix(imp, want+"/") {
					t.Errorf("%s: imports %q from non-test code (it imports testing, so it must stay test-only)", rel, want)
				}
			}
		}
	}
}