Mockito Made Clear

Adding Unit and Integration (End-to-End) Tests

For our purposes, an integration test is one that tests a system including components it interacts with (dependencies), whereas a unit test is one that tests a class in isolation with no interactions or dependencies.

Integration tests are often easier to understand because you’re treating the system as it’s used in practice, with no additional information about its implementation. In this case, the system is driven by the getAstroData method on the AstroService, which uses an AstroGateway. Its integration test looks like this:

AstroServiceTest.java

@Test
void testAstroData_usingRealGateway_withHttpClient() {
    // Create an instance of AstroService using the real Gateway
    service = new AstroService( ...