Introduce missing tests for Bean Override features

[sbrannen]

Overview

Over the past few weeks it has become apparent that our test suite does not fully cover all features of the Bean Override support in the TestContext framework.

To remedy that, we should introduce tests to cover corner cases and features that are currently not tested. As a starting point, we can adopt several of the tests for @MockBean and @SpyBean from Spring Boot's test suite.

Features to Test

The following is a list of features we should make sure we test before Spring Framework 6.2 GA.

• Combining SpringExtension and MockitoExtension on the same test class, including support for @Captor combined with @MockitoSpyBean.
• @MockitoBean, @MockitoSpyBean, and @TestBean with @DirtiesContext "before method" modes.
• @MockitoBean with JUnit 4 and SpringMethodRule.
• @MockitoBean and @MockitoSpyBean with @ContextHierarchy.
• @MockitoBean and @MockitoSpyBean with generics and parameterized types.
• @MockitoBean replacement of a bean with @Async methods.
• @MockitoBean replacement of a scoped proxy.
• @MockitoBean replacement of a Spring AOP proxy.
• @MockitoSpyBean with circular dependencies.
• Spring AOP proxy that wraps a Mockito spy created via @MockitoSpyBean.
• @MockitoSpyBean on a field with generics can be used to replace an existing bean with matching generics that's produced by a FactoryBean that's programmatically registered via an ImportBeanDefinitionRegistrar.
• @⁠MockitoBean and @⁠MockitoSpyBean can select a single candidate bean to override when there are multiple candidates that match the required type: via an explicit bean name, @⁠Qualifier, or @⁠Primary on one of the candidate beans.
• Mock reset support for beans within the ApplicationContext configured via MockReset.before() and MockReset.after().

Related Issues

• Recommend the use of AopTestUtils.getTargetObject() when setting expectations on a spied bean that Spring has proxied spring-boot#22281
• When using @MockitoBean and @MockitoSpyBean make it easier to inject any underlying proxy target as well as the mock or spy #33743
• @MockitoBean, @MockitoSpyBean, & @TestBean do not work with @DirtiesContext "before method" modes #33783
• Bean Overrides cannot reliably override beans created by a FactoryBean with generics #33811
• Test Bean Overrides do not honor @Primary semantics #33819
• MockReset should be honored without @Mockito[Spy]Bean fields #33829

[sbrannen]

After porting numerous tests from Spring Boot's test suite and introducing additional tests (see Related Issues and linked commits above), I am closing this task with the hope that we now have better coverage of the supported features for Bean Overrides.