### Question:
TransactionalFileStore implements FileStore, TransactionalResource { @Override public List<FilePath> list(final String directory, final String prefix) { return fileStore.list(directory, prefix); } TransactionalFileStore(final FileStore fileStore); @Override void begin(); @Override void commit(); @Override FileItem read(final FilePath filePath); @Override void write(final FilePath filePath, final FileItem fileItem); @Override void delete(final FilePath filePath); @Override void abort(); @Override List<FilePath> list(final String directory, final String prefix);  }### Answer:
@Test public void shouldList_withPrefix() throws Exception { final TransactionalFileStore transactionalFileStore = new TransactionalFileStore(mockFileStore); final String directory = Randoms.randomString(); final String prefix = Randoms.randomString(); transactionalFileStore.list(directory, prefix); verify(mockFileStore).list(directory, prefix); }
@Test public void shouldList_withNoPrefix() throws Exception { final TransactionalFileStore transactionalFileStore = new TransactionalFileStore(mockFileStore); final String directory = Randoms.randomString(); transactionalFileStore.list(directory, null); verify(mockFileStore).list(directory, null); }