)

type ZipTest struct {
	Name     string
	Source   func() (r io.ReaderAt, size int64) // if non-nil, used instead of testdata/<Name> file
	Comment  string
	File     []ZipTestFile
	Obscured bool  // needed for Apple notarization (golang.org/issue/34986)
	Error    error // the error that Opening this file should return
}

type ZipTestFile struct {
	Name     string
	Mode     fs.FileMode
	NonUTF8  bool
	ModTime  time.Time

			// should not happen
			t.Fatal(err)
		}
		tt.f(reader)
		err := reader.UnreadRune()
		if err == nil {
			t.Errorf("Unreading after %s: expected error", tt.name)
		}
	}
}

func TestReaderDoubleUnreadRune(t *testing.T) {
	buf := NewBuffer([]byte("groucho"))
	if _, _, err := buf.ReadRune(); err != nil {
		// should not happen
		t.Fatal(err)
	}