Automated Tests

In my blog post ‘How to use Spring Data’s Specification’ I showed you how you can write automated tests for your Spring Data Specifications. Although it explained how you can test a single specification, it missed a crucial part. The testing of composite specifications. In this follow-up post, I will close the gap left last time.

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The query methods of Spring Data JPA are a convenient way to retrieve data from your database. By simply defining methods in an interface, the framework can derive queries. For more complicated things, you can also define named queries and write your own JPQL or native SQL queries. However, with a growing application, this approach shows its drawbacks. New use-cases require new, but only slightly different, queries. The results are growing repositories that become harder and harder to maintain.
In this blog post, I’ll show you how to use Spring Data’s Specification to address this problem.

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In an integration test, we want to test the interaction of several components of our application. However, as soon as one of these components communicates with a 3rd party service via HTTP, this can present us with a challenge. To be independent of this service, we have to mock it. In this blog post, I will show you how to do that with the help of MockServer.

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Probably, the most annoying thing about integration tests is the need for testing infrastructure. If we want to test our Spring Data Repositories, we need a database. We could just use the H2 in-memory database provided by Spring Boot but the problem with this approach is, that H2 is probably not the database we use at runtime. This means, our integration tests don’t tell us if our code works as expected when it runs in the production environment. [Read More]

The idea of applications that provide their services over the web is anything but new. Chances are quite high that you already implemented such a service through a REST API. But before REST, there was a different approach to providing such services - SOAP. The release of Spring Boot 2.6.0 introduced a new test slice to test the components involved in providing these services. Let’s have a look at it!

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In this Blogpost, I’ll show you how to test the business logic inside your service classes. In the example, we will implement some plain Unit Tests. I will also discuss the downsides of this approach and why I prefer it over Integration Tests nonetheless.

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In this Blogpost, I will show you how to test the REST Clients of your Spring Boot Application with @RestClientTest. We will implement a repository that will fetch its data from the Star Wars API. By using the MockRestServiceServer we are going to mock the real API, to isolate our tests and fake inputs for our REST client to test its behavior. In the last part, I will show you how you can isolate the individual tests from another.

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In this Blogpost, I will show you how to test the MongoDB-based data layer of your Spring Boot Application with @DataMongoTest. While having a look at an example, we will bootstrap some test data, use an embedded in-memory MongoDB and write an actual MongoDB test.

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In this Blogpost, I will show you how to test the JPA-based data layer of your Spring Boot Application with @DataJpaTest. You will learn what happens when you use this annotation on a test class and a few ways to customize the default behavior. We will also have a look at an example where we will bootstrap some test data in different ways and write an actual JPA test.

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In this blog post, I will give you an overview of Spring Boot’s capabilities to test the data layer of your application.
There is a vast amount of technologies to choose from when it comes to loading and persisting data. There are not only completely different types of data stores but also different ways to communicate with them. Which combination is the most fitting, depends on your application. Whatever you choose, you should consider testing the components communicating with your data store, to prevent working with the wrong data.
The @Data*Test annotations of Spring Boot offer a great way to test these components in isolation while providing some handy niceties to make your life easier.

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