Add regression tests preventing committed tool binaries

pkg/cli/tracked_binaries_test.go

@@ -0,0 +1,89 @@
+//go:build !integration
+
+package cli
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// toolBinaryNames lists build-time tools that are installed via `go install` or
+// `go tool` (see the `tools` target in the Makefile). Their compiled binaries
+// must never be committed to the repository.
+var toolBinaryNames = []string{
+	"actionlint",
+	"gosec",
+	"govulncheck",
+	"golangci-lint",
+	"gopls",
+}
+
+// TestNoToolBinariesTracked ensures pre-built third-party tool binaries are not
+// committed to the repository. Committing them adds opaque compiled code to git
+// history and bypasses code review.
+func TestNoToolBinariesTracked(t *testing.T) {
+	repoRoot := repositoryRootForTest(t)
+
+	cmd := exec.Command("git", "ls-files", "-z")
+	cmd.Dir = repoRoot
+	output, err := cmd.Output()
+	if err != nil {
+		t.Skipf("Skipping test - unable to list tracked files: %v", err)
+	}
+
+	// git ls-files -z NUL-terminates every record, so drop the trailing separator.
+	byName := make(map[string]string)
+	for file := range strings.SplitSeq(strings.TrimSuffix(string(output), "\x00"), "\x00") {
+		if file != "" {
+			byName[filepath.Base(file)] = file
+		}
+	}
+	require.NotEmpty(t, byName, "Should find tracked files in the repository")
+
+	for _, name := range toolBinaryNames {
+		path, found := byName[name]
+		assert.Falsef(t, found, "Tool binary %q must not be committed (found at %q); it is installed via `go install`/`go tool`", name, path)
+	}
+}
+
+// TestToolBinariesGitignored ensures the tool binaries that were previously
+// committed by accident stay ignored so they cannot be committed again. Only
+// `actionlint` and `gosec` are checked because those are the tools whose binaries
+// end up in the repository root when built locally.
+func TestToolBinariesGitignored(t *testing.T) {
+	repoRoot := repositoryRootForTest(t)
+
+	content, err := os.ReadFile(filepath.Join(repoRoot, ".gitignore"))
+	require.NoError(t, err, "Should read .gitignore")
+
+	entries := make(map[string]bool)
+	for line := range strings.SplitSeq(string(content), "\n") {
+		entries[strings.TrimSpace(line)] = true
+	}
+
+	for _, name := range []string{"/actionlint", "/gosec"} {
+		assert.Truef(t, entries[name], ".gitignore should contain %q", name)
+	}
+}
+
+// repositoryRootForTest returns the root directory of this repository checkout.
+func repositoryRootForTest(t *testing.T) string {
+	t.Helper()
+
+	wd, err := os.Getwd()
+	require.NoError(t, err, "Should get current directory")
+
+	root, err := filepath.Abs(filepath.Join(wd, "..", ".."))
+	require.NoError(t, err, "Should resolve repository root")
+
+	if _, err := os.Stat(filepath.Join(root, ".gitignore")); err != nil {
+		t.Skipf("Skipping test - repository root not found: %v", err)
+	}
+	return root
+}