The SpringJUnitConfig and SpringJUnitWebConfig Annotations in Spring 5

1. Introduction

In this quick article, we’ll take a look at the new @SpringJUnitConfig and @SpringJUnitWebConfig annotations available in Spring 5.

These annotations are a composition of JUnit 5 and Spring 5 annotations that make test creation easier and faster.

2. @SpringJUnitConfig

@SpringJUnitConfig combines these 2 annotations:

• @ExtendWith(SpringExtension.class) from JUnit 5 to run the test with the SpringExtension class and
• @ContextConfiguration from Spring Testing to load the Spring context

Let’s create a test and use this annotation in practice:

@SpringJUnitConfig(SpringJUnitConfigTest.Config.class)
public class SpringJUnitConfigTest {

    @Configuration
    static class Config {}
}

Notice that, in contrast to the @ContextConfiguration, configuration classes are declared using the value attribute. However, resource locations should be specified with the locations attribute.

We can now verify that the Spring context was really loaded:

@Autowired
private ApplicationContext applicationContext;

@Test
void givenAppContext_WhenInjected_ThenItShouldNotBeNull() {
    assertNotNull(applicationContext);
}

Finally, here we have the equivalent code of @SpringJUnitConfig(SpringJUnitConfigTest.Config.class):

@ExtendWith(SpringExtension.class)
@ContextConfiguration(classes = SpringJUnitConfigTest.Config.class)

3. @SpringJUnitWebConfig

@SpringJUnitWebConfig combines the same annotations of @SpringJUnitConfig plus the @WebAppConfiguration from Spring testing – to load the WebApplicationContext.

Let’s see how this annotation works:

@SpringJUnitWebConfig(SpringJUnitWebConfigTest.Config.class)
public class SpringJUnitWebConfigTest {

    @Configuration
    static class Config {
    }
}

Like @SpringJUnitConfig, the configuration classes go in the value attribute and any resources are specified using the locations attribute.

Also, the value attribute of @WebAppConfiguration should now be specified using the resourcePath attribute. By default, this attribute is set to “src/main/webapp”.

Let’s now verify that the WebApplicationContext was really loaded:

@Autowired
private WebApplicationContext webAppContext;

@Test
void givenWebAppContext_WhenInjected_ThenItShouldNotBeNull() {
    assertNotNull(webAppContext);
}

Again, here we have the equivalent code without using @SpringJUnitWebConfig:

@ExtendWith(SpringExtension.class)
@WebAppConfiguration
@ContextConfiguration(classes = SpringJUnitWebConfigTest.Config.class)

4. Conclusion

In this brief tutorial, we showed how to use the newly introduced @SpringJUnitConfig and @SpringJUnitWebConfig annotations in Spring 5.

The full source code for the examples is available over on GitHub.