@Override
  public void start() {
    try {
      forceMkdir(fs.getUninstalledPluginsDir());
    } catch (IOException e) {
      throw new IllegalStateException("Fail to create the directory: " + fs.getUninstalledPluginsDir(), e);
    }
  }
@Test
  public void create_uninstall_dir() {
    File dir = new File(testFolder.getRoot(), "dir");
    when(fs.getUninstalledPluginsDir()).thenReturn(dir);

    assertThat(dir).doesNotExist();
    underTest.start();
    assertThat(dir).isDirectory();
  }