Test-Driven Java Development, Second Edition - Second Edition

Why not use unit tests exclusively?

At this moment, you might be wondering whether unit testing could provide a solution for all your testing needs. Unfortunately, that is not the case. While unit tests usually cover the biggest percentage of your testing needs, functional and integration tests should be an integral part of your testing toolbox.

We'll cover other types of tests in more detail in later chapters. For now, a few important distinctions between them are as follows:

• Unit tests try to verify small units of functionality. In the Java world, those units are methods. All external dependencies, such as invocations of other classes and methods or database calls, should be done in memory with the use of mocks, stubs, spies, fakes, and ...