if err != nil {
		t.Fatal(err)
	}

	// unlock the file
	if err = l.Close(); err != nil {
		t.Fatal(err)
	}

	// try lock the unlocked file
	dupl, err := LockedOpenFile(f.Name(), os.O_WRONLY|os.O_CREATE, 0o600)
	if err != nil {
		t.Errorf("err = %v, want %v", err, nil)
	}

	// blocking on locked file
	locked := make(chan struct{}, 1)
	go func() {