Mixing Unit and Spring Annotations

Direct Answer

A unit test can use annotations, including JUnit or Mockito annotations, without becoming an integration test. What matters is the boundary it exercises. Loading a Spring ApplicationContext to test real Spring wiring makes it an integration-style test; merely using a small Spring utility or annotation does not automatically do so. Prefer plain construction when framework behavior is not under test.

Code Example

@ExtendWith(MockitoExtension.class)
class PaymentServiceTest {
    @Mock // Mockito's mock, not Spring's
    private PaymentGateway paymentGateway;

    @Mock
    private OrderRepository orderRepository;

    @InjectMocks // Mockito injects mocks, not Spring
    private PaymentService paymentService;

    @Test
    void shouldProcessPaymentSuccessfully() {
        var order = new Order(1L, "Laptop", 1500.0);
        when(paymentGateway.charge(1500.0)).thenReturn(true);

        var result = paymentService.processPayment(order); // pure logic test

        assertTrue(result);
        verify(paymentGateway).charge(1500.0); // no Spring context involved
    }
}

Common Mistakes & Pitfalls

• Classifying by annotation name: The actual boundary and behavior under test matter more than whether a helper annotation comes from Spring.
• Loading @SpringBootTest for local logic: If wiring is not under test, direct construction gives a clearer, smaller test.
• Confusing mock scopes: @Mock creates a local Mockito mock. @MockitoBean, or @MockBean on older Boot, supplies or replaces a bean in a Spring test context.