### Question:
CacheStorageFiles { String getLayerFilename(DescriptorDigest layerDiffId) { return layerDiffId.getHash(); } CacheStorageFiles(Path cacheDirectory);   }### Answer:
@Test public void testGetLayerFilename() throws DigestException { DescriptorDigest diffId = DescriptorDigest.fromHash( "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"); Assert.assertEquals( "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb", TEST_CACHE_STORAGE_FILES.getLayerFilename(diffId)); }