AutoMock: Enhance your @WebMvcTest performance

What is AutoMock

SpringBoot supports @WebMvcTest annotation for convenience web layer(controller) slice test. When testing web layer, it is necessary to mock or spy beans that controller depends on using @MockBean and @SpyBean. However test specific controller through @WebMvcTest with @MockBean or @SpyBean affects test performance because it requires to reload spring context. Also it makes test context to handle lots of application context while testing.

AutoMock will automatically generate mock objects that our component depends on through constructor parameter type. So it will allows your @WebMvcTest to reuse spring test context and enhance your @WebMvcTest test performance

How to use

Basically we will test our controller layers like below

ASIS:

@WebMvcTest(MockBeanController.class)
public class MockBeanTest {

    @MockBean
    private MockBeanService mockBeanService;
    
}

If you use AutoMock, Mock object will be created and registered in bean factory. So field injection through autowired is possible instead of @MockBean like below. Be aware that controller is not specified in @WebMvcTest. Specify controller will also require spring test context to be created. So do not specify controllers.

@WebMvcTest
public class MockBeanTest {

    @Autowired
    private MockBeanService mockBeanService;
    
}

Getting started

build.gradle

testImplementation 'io.github.mangkyu:spring-boot-test-automock:0.0.4'

Be aware

• Currently automock not supports spying
• Currently mock object is generated based on constructor parameter type
• As it does not specify controller, any controller's api can be called by mockmvc