@Test
  public void testCombineValuesFnCoders() throws Exception {
    CoderRegistry registry = new CoderRegistry();
    registry.registerStandardCoders();

    MeanInts meanInts = new MeanInts();
    MeanInts.CountSum countSum = meanInts.new CountSum(6, 27);

    Coder<MeanInts.CountSum> coder =
        meanInts.getAccumulatorCoder(
            registry, registry.getDefaultCoder(TypeDescriptor.of(Integer.class)));

    assertEquals(
        countSum,
        CoderUtils.decodeFromByteArray(coder, CoderUtils.encodeToByteArray(coder, countSum)));
  }
 private void checkRegistry(Class<? extends Mutation> mutationClass)
     throws CannotProvideCoderException {
   Coder<? extends Mutation> coder = registry.getCoder(TypeDescriptor.of(mutationClass));
   assertNotNull(coder);
   assertEquals(HBaseMutationCoder.class, coder.getClass());
 }
 @Test
 public void testIncrementThrowsCannotProvideCoderException() throws Exception {
   expectedException.expect(CannotProvideCoderException.class);
   registry.getCoder(TypeDescriptor.of(Increment.class));
 }