public void cancelUninstalls() {
    for (File file : listJarFiles(fs.getUninstalledPluginsDir())) {
      try {
        moveFileToDirectory(file, fs.getInstalledExternalPluginsDir(), false);
      } catch (IOException e) {
        throw new IllegalStateException("Fail to cancel plugin uninstalls", e);
      }
    }
  }
@Test
  public void cancel() throws IOException {
    File file = copyTestPluginTo("test-base-plugin", uninstallDir);
    assertThat(Files.list(uninstallDir.toPath())).extracting(p -> p.getFileName().toString()).containsOnly(file.getName());
    underTest.cancelUninstalls();
  }