Spring Boot Integration Testing

A Spring test suite goes from forty seconds to eleven minutes without a single line of business logic being added. The cause is almost always the same: the application context is rebuilt dozens of times. Spring caches the context and reuses it across test classes, but only if the requested configuration is strictly identical. A class that adds a @MockBean, a @TestPropertySource property, or a different profile gets a different cache key, which means a fresh context, which means three to eight extra seconds of startup. Twenty configuration variants means twenty startups.

The second pitfall is the mirror image: annotating every test class with @SpringBootTest for convenience. You then load the full container — security, scheduler, HTTP clients, message listeners — to test a fifteen-line SQL query. The test is slow, and it fails for reasons unrelated to what it verifies: an infrastructure bean missing in the test environment is enough to bring down a class that never touches it. The skill to acquire here is to load as little as possible while remaining realistic, and to limit the number of distinct configurations in the project.