{Name: "subfolder/another.go", Data: []byte("world"), Mode: 0644},
		// Notably missing here is the "subfolder" directory. This makes sure even
		// if we don't have a subfolder directory listed.
	}
	err := w.AddFS(writeTestsToFS(tests))
	if err != nil {
		t.Fatal(err)
	}
	if err := w.Close(); err != nil {
		t.Fatal(err)
	}

	// Add subfolder into fsys to match what we'll read from the tar.

	fsys := fstest.MapFS{
		"emptyfolder":          {Mode: 0o755 | os.ModeDir},
		"file.go":              {Data: []byte("hello")},
		"subfolder/another.go": {Data: []byte("world")},
		// Notably missing here is the "subfolder" directory. This makes sure even
		// if we don't have a subfolder directory listed.
	}
	var buf bytes.Buffer
	tw := NewWriter(&buf)
	if err := tw.AddFS(fsys); err != nil {
		t.Fatal(err)
	}

	dataScannerCompactAtFolders      = dataScannerCompactAtChildren / 4 // Compact when this many subfolders in a single folder.
	dataScannerForceCompactAtFolders = 250_000                          // Compact when this many subfolders in a single folder (even top level).
	dataScannerStartDelay            = 1 * time.Minute                  // Time to wait on startup and between cycles.