Mockito Made Clear

Using the Existing Argument Matchers

The ProjectService class from Chapter 2, ​Work with the Mockito API​, contains a method called findByIds(int...). That method in turn calls the findById(int) method on the PersonRepository, which we needed to mock to isolate our PersonService for testing. Here’s a test of the service method for the case where the requested ID doesn’t exist in the database:

PersonServiceTest.java

@Test
public void findByIdThatDoesNotExist() {
    when(repository.findById(anyInt()))
        .thenReturn(Optional.empty());

    List<Person> personList = service.findByIds(999);
    assertTrue(personList.isEmpty());

    verify(repository).findById(anyInt());
}

The anyInt method was used both when setting the expectations and when verifying ...