add-e2e-test-layer

To add end-to-end tests, you can create an e2eTest source set that uses @SpringBootTest(RANDOM_PORT) to verify the embedded server starts and real HTTP endpoints behave correctly. This provides startup confidence and actuator health assertions over real HTTP.

The best way to test real HTTP behavior for the Actuator health endpoint is to use RestTestClient within an ApplicationTests class, asserting that the /actuator/health endpoint returns UP status against a randomly ported embedded server.

You can configure integration testing in Gradle by registering an e2eTest task that runs after the componentTest task, wiring it into tasks.check and JaCoCo ordering to include end-to-end verification in the standard build lifecycle.

Yes, you can use RestTestClient with JUnit 5 for end-to-end testing in Spring Boot 4 by generating an ApplicationTests class that asserts real HTTP responses, ensuring your REST endpoints are reachable and application health is UP.

You need a separate e2eTest source set when you want to chain acceptance verification after component tests, using RANDOM_PORT to run tests against the application like a real deployment to validate embedded server startup and actuator behavior.