### Question:
SegmentedCacheFunction implements CacheFunction { @Override public Bytes key(Bytes cacheKey) { return Bytes.wrap(bytesFromCacheKey(cacheKey)); } SegmentedCacheFunction(KeySchema keySchema, long segmentInterval); @Override Bytes key(Bytes cacheKey); @Override Bytes cacheKey(Bytes key); long segmentId(Bytes key);  }### Answer:
@Test public void key() throws Exception { assertThat( cacheFunction.key(THE_CACHE_KEY), equalTo(THE_KEY) ); }