@Test
public void testAsyncOperation() {

    FunctionTestHarness harness = FunctionTestHarness.test(new TestProvider(), MERCHANT_FN, SELF_ID);
    Assert.assertThat(
            harness.invoke(CALLER, QueryMerchantScore.getDefaultInstance()),
            sent(messagesTo(CALLER, equalTo(MerchantScore.newBuilder().setScore(1).build()))));
}