### Question:
DelegateIncrementalFileMergerInput implements IncrementalFileMergerInput { @Nullable @Override public FileStatus getFileStatus(@NonNull String path) { return delegate.getFileStatus(path); } DelegateIncrementalFileMergerInput(@NonNull IncrementalFileMergerInput delegate); @Override void open(); @Override void close(); @NonNull @Override ImmutableSet<String> getUpdatedPaths(); @NonNull @Override ImmutableSet<String> getAllPaths(); @NonNull @Override String getName(); @Nullable @Override FileStatus getFileStatus(@NonNull String path); @NonNull @Override InputStream openPath(@NonNull String path);  }### Answer:
@Test public void fileStatus() { delegate.getFileStatus("foo"); Mockito.verify(mockInput).getFileStatus(Matchers.eq("foo")); }