Instead of using the springboot-starter-test dependency, we'll learn how to write a unit test using the Spring test features in this lesson.
We start by replacing the springboot-starter-test dependency — which is automatically included in a Spring Boot project — with the spring-test dependency along with the junit-jupiter-engine dependency.
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<scope>test</scope>
</dependency><dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<scope>test</scope>
</dependency>Since the project was built using Spring Boot, removing the springboot-starter-test dependency leads to compilation errors due to usage of the @SpringBootTest annotation in src/test/java. To remove the errors, we can comment out the @SpringBootTest annotation.
To load the context using Spring, we will use @ContextConfiguration. This loads only part of the configuration and is thus more suitable for unit testing.
Since our configuration is in the class MovieRecommenderSystemApplication, we will pass that as an argument to the @ContextConfiguration annotation. This class is where the context is present.
After the context has been defined, we need to run it. This is done by using the @ExtendWith annotation with SpringExtension.class as its argument. SpringExtension provides a bridge between Spring and JUnit.
//load context and run it
@ExtendWith(SpringExtension.class)
@ContextConfiguration(classes=MovieRecommenderSystemApplication.class)
class RecommenderImplementationSpringTest {
}The rest of the test is the same as it was in the prior lesson.
A class which does not provide a constructor or setter injection for its dependencies can only be tested by loading the Spring context. However, if a constructor is present (as in the case of RecommenderImplementation class shown above), the object can be created without loading the context, and it can also be mocked (Unit Testing in Spring lesson.)