chore: import upstream snapshot with attribution

internal/workspace/workspace_gitignore_test.go

@@ -0,0 +1,72 @@
+package workspace
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestEnsureIndexDirGitignore(t *testing.T) {
+	read := func(dir string) string {
+		b, err := os.ReadFile(filepath.Join(dir, ".gitignore"))
+		if err != nil {
+			t.Fatalf("read .gitignore: %v", err)
+		}
+		return string(b)
+	}
+
+	// created: an empty index dir gets the default written.
+	t.Run("created", func(t *testing.T) {
+		dir := t.TempDir()
+		wrote, err := EnsureIndexDirGitignore(dir)
+		if err != nil || !wrote {
+			t.Fatalf("wrote=%v err=%v, want wrote=true", wrote, err)
+		}
+		if got := read(dir); got != DefaultIndexGitignore {
+			t.Errorf("content = %q, want default", got)
+		}
+	})
+
+	// unchanged: a dir already holding the current default is a no-op.
+	t.Run("unchanged", func(t *testing.T) {
+		dir := t.TempDir()
+		if _, err := EnsureIndexDirGitignore(dir); err != nil {
+			t.Fatal(err)
+		}
+		wrote, err := EnsureIndexDirGitignore(dir)
+		if err != nil || wrote {
+			t.Errorf("second call wrote=%v err=%v, want wrote=false", wrote, err)
+		}
+	})
+
+	// healed: a stale bare-`*` default is rewritten to the current default.
+	t.Run("healed", func(t *testing.T) {
+		dir := t.TempDir()
+		if err := os.WriteFile(filepath.Join(dir, ".gitignore"), []byte("*\n"), 0o644); err != nil {
+			t.Fatal(err)
+		}
+		wrote, err := EnsureIndexDirGitignore(dir)
+		if err != nil || !wrote {
+			t.Fatalf("heal wrote=%v err=%v, want wrote=true", wrote, err)
+		}
+		if got := read(dir); got != DefaultIndexGitignore {
+			t.Errorf("healed content = %q, want default", got)
+		}
+	})
+
+	// kept: a user-customized .gitignore is left untouched.
+	t.Run("kept", func(t *testing.T) {
+		dir := t.TempDir()
+		const custom = "!keepme.json\nstore.sqlite\n"
+		if err := os.WriteFile(filepath.Join(dir, ".gitignore"), []byte(custom), 0o644); err != nil {
+			t.Fatal(err)
+		}
+		wrote, err := EnsureIndexDirGitignore(dir)
+		if err != nil || wrote {
+			t.Errorf("kept wrote=%v err=%v, want wrote=false", wrote, err)
+		}
+		if got := read(dir); got != custom {
+			t.Errorf("customized content was altered: %q", got)
+		}
+	})
+}