@Test public void returnValueNotCached() throws Exception {
    Method method = getRecordingMethod();
    EventProducer producer = new EventProducer(this, method);
    producer.produceEvent();
    methodReturnValue = new Object();
    methodCalled = false;
    Object secondReturnValue = producer.produceEvent();

    assertTrue("Producer must call provided method twice.", methodCalled);
    assertSame("Producer result must be *exactly* the specified return value on each invocation.",
        secondReturnValue, methodReturnValue);
  }
Checks that EventProducer's constructor disallows null targets.
otto/src/test/java/com/squareup/otto/EventProducerTest.java