LongSummer implements Reducer<Long> { @Override public Long reduce(Long v1, Long v2) { return v1 + v2; }  @Override Long reduce(Long v1, Long v2); @Override Long zero(); @Override boolean isZero(Long aLong);  }
@Test(dataProvider = "getLong") public void testReduce(long v1, long v2, long sum) { assertThat(summer.reduce(v1, v2)).isEqualTo(sum); }