In one of our core services, the execution of a single unit test took approximately 30 seconds, while a single integration test ranged between 65 and 70 seconds. Running the entire test suite took circa 6 minutes.
Spring is one of the most popular JVM-targeted frameworks. One of the reasons why it has become so popular is writing tests. Even before Spring Boot era, it was easy to run an embedded Spring application in tests. With Spring Boot, it became trivial. JUnit and Spock are two most popular frameworks for writing tests. They both provide great support and integration with Spring, but until recently it was not possible to leverage Spring’s @WebMvcTest in Spock. Why does it matter? @WebMvcTest is a type of an integration test that only starts a specified slice of Spring Application and thus its execution time is significantly lower compared to full end-to-end tests. Things have changed with Spock 1.2. Let me show you, how to leverage this new feature.
The first question is — what is overmocking? There are a couple of answers. When you mock something that you can leave or even should use as it is — this is overmocking. An example of this is a POJO object. Other way to overmock your test is to mock all the dependencies and rely only on verifying interactions with mock objects. You will see that in my examples. Overmocking can also happen when you mock something that you don’t own like an external library.
One of the major goals of software development, apart from actually delivering the product, is to guarantee it is of proper quality and not prone to errors. Big modern systems tend to consist of dozens of smaller pieces, often accompanied by some legacy core or part of legacy system. Each of these, often very different pieces of software communicate with each other in some way, in synchronous or asynchronous way, through REST endpoints, SOAP services or a variety of messaging systems. This leads to new challenges. A failure or unexpected change in one place may lead to a misbehaviour in other parts of the system.
