### Question:
InMemoryCache { public synchronized void putFeature(Feature feature) { features.put(feature.getId(), feature); } @Inject  InMemoryCache(); synchronized void putFeature(Feature feature); void removeFeature(String id); synchronized ImmutableSet<Feature> getFeatures(); void clear(); Optional<Feature> getFeature(String featureId);  }### Answer:
@Test public void putFeature() { inMemoryCache.putFeature(FAKE_FEATURE); assertThat(inMemoryCache.getFeatures()).containsExactly(FAKE_FEATURE); }