Validate that JUnit Jupiter test methods and lifecycle methods are not annotated with @Autowired

[rwinch]

It would be nice to consider adding validation of @Autowired on tests. For example, a user may be trying to use parameter injection of their beans and accidentally place @Autowired on the method rather than on the parameters. For example the following:

@Test
@Autowired
@WithMockUser
void go(MessageService messageService) {
	assertThat(messageService).isNotNull();
	assertThat(SecurityContextHolder.getContext().getAuthentication()).isNotNull();
}

will be invoked when the test is autowired. It would fail because Spring Security's TestExecutionListener is not invoked until the time of test rather than injection. The failure looks something like this:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'example.demo.WithMockUserAutowiredMethodTest': Injection of autowired dependencies failed; nested exception is java.lang.AssertionError: 
Expecting actual not to be null
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:405)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1420)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireBeanProperties(AbstractAutowireCapableBeanFactory.java:392)
	at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:119)
	at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)
	at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:244)
	at org.springframework.test.context.junit.jupiter.SpringExtension.postProcessTestInstance(SpringExtension.java:98)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeTestInstancePostProcessors$5(ClassBasedTestDescriptor.java:341)
	...
Caused by: java.lang.AssertionError: 
Expecting actual not to be null
	at example.demo.WithMockUserAutowiredMethodTest.withMockUserWhenAutowiredMethodThenSecurityContextSetup(WithMockUserAutowiredMethodTest.java:23)

I think it would be nice to add validation around what methods are @Autowired to ensure they are not on methods that are also annotated with JUnit Jupiter methods to give users a more clear explanation as to what is wrong.

Related Discussion: #18629 (comment)

[sbrannen]

Tentatively slated for 5.3 GA in case I determine that it's feasible to implement it before the release.