The SpringJUnitConfig and SpringJUnitWebConfig Annotations in Spring

Last updated: January 8, 2024

Written by: Marcos Lopez Gonzalez

Reviewed by: Darragh Pigott

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1. Introduction

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

These annotations are a composition of JUnit 5 and Spring 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

2.1. Test Configuration

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

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

    @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)

2.2. The loader Attribute

One of the attributes of @ContextConfiguration named loader wasn’t an attribute in @SpringJUnitConfig when it was initially released. In a case where we need to explicitly set a custom loader, we have to revert to the lower-level annotations:

@ExtendWith(SpringExtension.class)
@ContextConfiguration(loader = SpringConfigTest.class)

As of Spring version 6 and Spring Boot version 3.2.0, the loader attribute is available as a parameter in the @SpringJUnitConfig annotation. This provides support for configuring a custom ContextLoader or SmartContextLoader.

For example, let’s explicitly specify annotation-based loading directly in the @SpringJUnitConfig annotation:

@SpringJUnitConfig(classes = TestConfig.class, loader = AnnotationConfigContextLoader.class)
public class SpringJUnitConfigurationUnitTest {
    @ParameterizedTest
    @ValueSource(strings = { "Dilbert", "Wally" })
    void whenSetPeopleWithName_thenListContainsOnePerson(String name, @Autowired List people) {
        assertThat(people.stream()
          .map(Person::getName)
          .filter(name::equals)).hasSize(1);
    }
}

Using the loader attribute, we have a simpler test configuration without the need for multiple annotations.

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(SpringJUnitWebConfigIntegrationTest.Config.class)
public class SpringJUnitWebConfigIntegrationTest {

    @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 = SpringJUnitWebConfigIntegrationTest.Config.class)

Similarly, Spring version 6 and Spring Boot version 3.2.0 add loader support to @SpringJUnitWebConfig to configure a custom context loader for tests. This gives the annotation the full capabilities of @ContextConfiguration annotation.

4. Conclusion

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

The code backing this article is available on GitHub. Once you're logged in as a Baeldung Pro Member, start learning and coding on the project.

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To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

Try a 14-Day Free Trial of Orkes Conductor today.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

Try a 14-Day Free Trial of Orkes Conductor today.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.