### Question:
BfdFeature extends AbstractFeature { @Override public Optional<SwitchFeature> discover(IOFSwitch sw) { Optional<SwitchFeature> empty = Optional.empty(); SwitchDescription description = sw.getSwitchDescription(); if (description == null || description.getSoftwareDescription() == null) { return empty; } if (!NOVIFLOW_SOFTWARE_DESCRIPTION_REGEX.matcher(description.getSoftwareDescription()).matches()) { return empty; } return Optional.of(SwitchFeature.BFD); }  @Override Optional<SwitchFeature> discover(IOFSwitch sw);  }### Answer:
@Test public void testDiscoverOfSwitchWithoutBfdSupport() { Assert.assertFalse(bfdFeature.discover(createSwitchWithDescription(null)).isPresent()); assertWithoutBfdSupport("2.8.16.21"); assertWithoutBfdSupport("2.8.16.15"); assertWithoutBfdSupport("8.1.0.14"); }