@TargetApi(21)
  public String getNoBackupFilesDirectoryPath() {
    return Build.VERSION.SDK_INT >= 21 &&
            this.context != null
            ? absPath(this.context.getNoBackupFilesDir())
            : "";
  }
@Test
  public void getNoBackupFilesDirectoryPathIsNotEmpty() {
    assertThat(contextUtil.getNoBackupFilesDirectoryPath(), endsWith("/no_backup"));
  }