### Question:
ObjectCache { public boolean contains(ObjectId id) { return sharedCache.get().contains(keyPrefix.create(id)); } ObjectCache(Supplier<SharedCache> cache, CacheIdentifier prefix); boolean contains(ObjectId id); void invalidateAll(); void invalidate(ObjectId id); void put(RevObject obj); @Nullable RevObject getIfPresent(ObjectId id);  }### Answer:
public @Test void testContains() { when(mockSharedCache.contains(eq(k11))).thenReturn(false); when(mockSharedCache.contains(eq(k21))).thenReturn(true); assertFalse(cache1.contains(o1.getId())); assertTrue(cache2.contains(o1.getId())); }