How did you conduct testing of microservices interaction in your last project?

For testing microservices interaction in my last project, I used several approaches:

1. Integration tests — running multiple services together in a test environment and checking their interaction through real API calls.

2. Contract testing (Consumer-Driven Contracts) — using tools like Pact to verify that services adhere to API agreements, reducing the risk of breakages during changes.

3. Mocking external services — using mocks or stubs to isolate the tested service and emulate responses from other microservices.

4. End-to-End tests — executing scenarios that pass through several services to verify the entire business logic.

Example of using Spring Boot for an integration test with MockMvc:

@SpringBootTest
@AutoConfigureMockMvc
public class UserServiceIntegrationTest {

    @Autowired
    private MockMvc mockMvc;

    @Test
    public void testGetUserDetails() throws Exception {
        mockMvc.perform(get("/users/1"))
               .andExpect(status().isOk())
               .andExpect(jsonPath("$.id").value(1));
    }
}