public Optional<PluginMatchingResult<PortScanner>> getPortScanner() {
    ImmutableList<PluginMatchingResult<PortScanner>> allPortScanners = getPortScanners();

    return allPortScanners.isEmpty() ? Optional.empty() : Optional.of(allPortScanners.get(0));
  }
@Test
  public void getPortScanner_whenNoPortScannersInstalled_returnsEmptyOptional() {
    PluginManager pluginManager =
        Guice.createInjector(
                new FakeServiceFingerprinterBootstrapModule(),
                new FakeVulnDetectorBootstrapModule())
            .getInstance(PluginManager.class);

    assertThat(pluginManager.getPortScanner()).isEmpty();
  }