`@MockitoSpyBean` does not support transparent verification

[sbrannen]

Overview

SpringAopBypassingVerificationStartedListener provides partial support for transparent verification for Mockito spies created via @MockitoSpyBean when the spy is wrapped in a Spring AOP proxy.

However, the following @Disabled test currently fails since the AOP proxy for the DateService is not considered a mock by Mockito.

spring-framework/spring-test/src/test/java/org/springframework/test/context/bean/override/mockito/MockitoSpyBeanAndAopProxyTests.java

Lines 88 to 117 in 982f7f8

	/**
	* Verification for a Mockito spy that is wrapped in a Spring AOP proxy should
	* always work when performed via the Spring AOP proxy. However, stubbing
	* does not currently work via the Spring AOP proxy.
	*
	* <p>Consequently, this test method supplies the ultimate target of the Spring
	* AOP proxy to stubbing calls, while supplying the Spring AOP proxy to verification
	* calls.
	*/
	@Disabled("Disabled until transparent verification for @MockitoSpyBean is implemented")
	@Test
	void stubOnUltimateTargetAndVerifyOnSpringAopProxy() {
	assertThat(AopUtils.isAopProxy(dateService)).as("is Spring AOP proxy").isTrue();
	DateService spy = AopTestUtils.getUltimateTargetObject(dateService);
	assertThat(Mockito.mockingDetails(spy).isSpy()).as("ultimate target is Mockito spy").isTrue();
	given(spy.getDate(false)).willReturn(1L);
	Long date = dateService.getDate(false);
	assertThat(date).isOne();
	given(spy.getDate(false)).willReturn(2L);
	date = dateService.getDate(false);
	assertThat(date).isEqualTo(1L); // 1L instead of 2L, because the AOP proxy caches the original value.
	// Each of the following verifies times(1), because the AOP proxy caches the
	// original value and does not delegate to the spy on subsequent invocations.
	verify(dateService, times(1)).getDate(false);
	verify(dateService, times(1)).getDate(eq(false));
	verify(dateService, times(1)).getDate(anyBoolean());
	}

To provide transparent verification support for @MockitoSpyBean, we need to implement and register a Mockito MockResolver, analogous to the SpringBootMockResolver in Spring Boot.

Related Issues

• AopTestUtils.getUltimateTargetObject results in stack overflow for proxy backed by LazyInitTargetSource #29215 (comment)
• SpringBootMockResolver causes AopTestUtils.getUltimateTargetObject to recurse until the stack overflows when it calls it with Spring Security's authentication manager bean spring-boot#32632
• Allow proxied @SpyBeans to be used with Mockito's inline mock maker spring-boot#22416
• mockito3.4.0 InlineByteBuddyMockMaker can't work with spring cglib proxy, but ByteBuddyMockMaker works mockito/mockito#1980

[philwebb]

This unfortunately breaks code that doesn't have spring-aop on the classpath.