Testing Spring Boot with JUnit5

I decided that is time to move my tests in Spring app from JUnit 4 to Jupiter. It is not too complicated, given that Spring is already supporting JUnit 5, even though the default is still the previous version. However it requires being careful in a couple of steps.

Firstly, I have changed the POM in this way:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
    <exclusions>
        <exclusion>
            <!-- get rid of JUnit 4 -->
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </exclusion>
    </exclusions>
</dependency>

<!-- using JUnit 5 instead -->
<dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter-engine</artifactId>
    <!-- using the version set by Spring -->
    <scope>test</scope>
</dependency>

I have excluded JUnit 4 from the spring-boot-starter-test dependency, and then I have inserted a new dependency for Jupiter, all of them are obviously in the test scope. Notice that I didn't set the version for JUnit 5, accepting instead the one proposed by Spring. Just to stay on the safe side.

The changes in "normal" testing are quite simple, usually limited in using the right imports for the new library. Something a bit more engaging is to be done for Spring Application test. What I had for JUnit 4 was something like this

@RunWith(SpringRunner.class)
@SpringBootTest
public class MyApplicationTests {
    // ...

In Jupiter, however, the annotation RunWith has been replaced with the more powerful ExtendWith, so the code has to be changed to

@ExtendWith(SpringExtension.class)
@SpringBootTest
public class MyApplicationTests {
    // ...

Not too bad, isn't it?