@Test
  public void testPutEmptyValue() {
    byte[] emptyValue = new byte[0];
    this.inMemoryKeyValueStore.put(key(0), emptyValue);

    assertEquals(0, this.inMemoryKeyValueStore.get(key(0)).length);
    verify(this.putsCounter).inc();
    verify(this.bytesWrittenCounter).inc(DEFAULT_KEY_LENGTH);
  }
The length of the result of {@link #value(int)} will always be the same, so this can be used as the length for any
key produced by {@link #value(int)}.
samza-kv-inmemory/src/test/java/org/apache/samza/storage/kv/inmemory/TestInMemoryKeyValueStore.java