@Test
@PrepareForTest(File.class)
public void testRake() {

  // Given
  final File base = mock(File.class);
  // When
  final FileWatcher fileWatcher = new FileWatcher(base);
  final HashSet<File> checked = new HashSet<>();
  final HashSet<File> changed = new HashSet<>();
  fileWatcher.rake(checked, changed);
  // Then
}