springboot-mockito

The main goal of this project is to explore basics od Mockito in Spring Boot environment.

manual

• add @ExtendWith(MockitoExtension.class) to the class

• mocking

  1. no args

     CustomerRepository customerRepository = mock(CustomerRepository.class);
     when(customerRepository.findAll()).thenReturn(Collections.singletonList(customer1));
     

  2. regardless argument

     CustomerRepository customerRepository = mock(CustomerRepository.class);
     when(customerRepository.findById(any(Integer.class))).thenReturn(Optional.of(customer1));
     

  3. specific argument

     CustomerRepository customerRepository = mock(CustomerRepository.class);
     when(customerRepository.findById(1)).thenReturn(Optional.of(customer1));
     

  • Note that: when(...).thenReturn(...) and doReturn(...).when(...) are equivalent for mocks, they differ when comes to spy:
    • when thenReturn - makes a real method call just before the specified value will be returned (if the called method throws an Exception you have to deal with it and you still get the result),
    • doReturn when - does not call the method at all.

• to verify how many times method was invoked:

  1. once (no args)

     verify(customerRepository).findAll();
     

  2. twice (specific argument)

     verify(customerRepository, times(2)).findAll();
     

  3. at least once (regardless argument)

     verify(customerRepository, atLeast(1)).findById(any(Integer.class));
     

  4. at most once

     verify(customerRepository, atMost(1)).findById(2);
     

  5. zero

     verify(customerRepository, never()).findById(2);
     

tests

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