Search⌘ K
AI Features
Home
Courses
The Complete Guide to Spring 6 and Spring Boot 3

Unit Testing in Spring

Explore how to implement unit tests in Spring applications using JUnit and Mockito. Understand the best practices for separating test and production code, using constructor injection for dependencies, and verifying method outputs with assertions. This lesson teaches you to create focused and maintainable unit tests for Spring components to improve application reliability.

We'll cover the following...

When writing tests, the foremost thing to remember is that the test code should always be separate from the production code. We will write all our tests in src/test/java. This will ensure that the test code is never part of the deployable jar or war and stays in our repository.

We will now write unit tests for the RecommenderImplementation class created earlier in this course. The code of the class is reproduced below:

Java
@Component
public class RecommenderImplementation {
  @Autowired
  private Filter filter;
    
  public RecommenderImplementation(Filter filter) {
    super();
    this.filter = filter;
  }
  //use a filter to find recommendations
  public String [] recommendMovies (String movie) {
    String[] results = filter.getRecommendations(movie);
    return results;
  }
}

This class has a dependency on the Filter interface, which has two implementations, ContentBasedFilter and CollaborativeFilter. Autowiring of the Filter ...