UniversalImageCache implements ImageCache,
		MemoryCacheAware<String, Bitmap> { @Override public Collection<String> keys() { return this.delegate.keys(); } UniversalImageCache(MemoryCacheAware<String, Bitmap> delegate); @Override boolean put(String key, Bitmap value); @Override Bitmap get(String key); @Override void remove(String key); @Override Collection<String> keys(); @Override void clear(); @Override Bitmap getBitmap(String key); @Override void putBitmap(String key, Bitmap bitmap);  }
@Test public void keysShouldContainCachedKey() { given(delegate.keys()).willReturn(Arrays.asList(key)); Collection<String> keys = imageCache.keys(); assertTrue(keys.contains(key)); }