### Question:
PlatformManager { Collection<PlatformLevel> getPlatformLevels () { return getPlatforms().stream().map(Platform::getPlatformLevel).collect(Collectors.toCollection(HashSet::new)); } @Autowired  PlatformManager();   PlatformManager(Collection<Platform> platforms); Collection<Platform> getPlatforms(); Optional<Platform> getNextPlatformForExperiment(boolean force);  }### Answer:
@Test public void getPlatformLevels () { when(platform1.getPlatformLevel()).thenReturn(PlatformLevel.IAAS); when(platform2.getPlatformLevel()).thenReturn(PlatformLevel.PAAS); Collection<PlatformLevel> platformLevels = platformManager.getPlatformLevels(); assertThat(platformLevels, IsIterableContainingInAnyOrder.containsInAnyOrder(PlatformLevel.PAAS, PlatformLevel.IAAS)); assertThat(platformLevels, not(Matchers.hasItem(PlatformLevel.SAAS))); assertThat(platformLevels, not(Matchers.hasItem(PlatformLevel.OVERALL))); }