@Test
public void initNonemptyNotebookDir() throws IOException, GitAPIException {

  //given - .git does not exit
  File dotGit = new File(Joiner.on(File.separator).join(notebooksDir, ".git"));
  assertThat(dotGit.exists()).isEqualTo(false);
  //when
  notebookRepo = new GitNotebookRepo(conf);
  //then
  Git git = notebookRepo.getGit();
  assertThat(git).isNotNull();
  assertThat(dotGit.exists()).isEqualTo(true);
  assertThat(notebookRepo.list(null)).isNotEmpty();
  List<DiffEntry> diff = git.diff().call();
  // no commit, diff isn't empty
  assertThat(diff).isNotEmpty();
}