fsys := fstest.MapFS{
		"file.go":              {Data: []byte("hello")},
		"subfolder/another.go": {Data: []byte("world")},
	}
	var buf bytes.Buffer
	tw := NewWriter(&buf)
	if err := tw.AddFS(fsys); err != nil {
		t.Fatal(err)
	}

	// Test that we can get the files back from the archive
	tr := NewReader(&buf)

	entries, err := fsys.ReadDir(".")
	if err != nil {
		t.Fatal(err)

		{
			Name: "file.go",
			Data: []byte("hello"),
			Mode: 0644,
		},
		{
			Name: "subfolder/another.go",
			Data: []byte("world"),
			Mode: 0644,
		},
	}
	err := w.AddFS(writeTestsToFS(tests))
	if err != nil {
		t.Fatal(err)
	}

	if err := w.Close(); err != nil {
		t.Fatal(err)
	}

	// read it back