if !isClosed {
		t.Fatal("File ref count should be zero")
	}

	// Closing a file again should result in invalid argument.
	if err = rlk.Close(); err != os.ErrInvalid {
		t.Fatal(err)
	}

	_, err = newRLockedFile(nil)
	if err != os.ErrInvalid {
		t.Fatal("Unexpected error", err)
	}
}

// Tests lock and unlock semantics.
func TestLockAndUnlock(t *testing.T) {
	f, err := os.CreateTemp(t.TempDir(), "lock")