My context: Backend Java/Kotlin dev. Don't really need any fancy test framework, JUnit 5 is absolutely fine for executing the tests. But I do use a bunch of add

My context: Backend Java/Kotlin dev. Don't really need any fancy test framework, JUnit 5 is absolutely fine for executing the tests. But I do use a bunch of additional tools and libraries. testcontainers so I can write proper integration tests instead of mocking dependencies away. AssertJ for fancy assertions with great failure messages. Mockito for the rare mocking/spy usage. Awaitility for the rare async/timing based test. When there is a Frontend (templated or SPA, doesn't matter), I like writing the tests with Selenide assertions and using its Selenium integration to run against a large array of browsers + variants (Chrome, FF, Mobile etc) launched via testcontainers.