← Spring Boot

Testing

01 What is @SpringBootTest and when should it be used?

Solution and explanation

Solution:

Testing should happen at different levels.

Unit test:

Tests one class.

Example:

JobService

Integration test:

Tests several real Spring components.

Example:

Controller
Service
Repository
Database

@SpringBootTest:

Loads the Spring Boot application context.

This is useful when we want to verify that the actual application wiring works.

Example:

POST /api/jobs

Request enters:

Controller
|
Service
|
Repository
|
Database

A broad integration test can verify the complete flow.

However, using @SpringBootTest for every small test can make the test suite slow.

Use unit tests for isolated business logic and integration tests for important interactions.

Run this example

        @SpringBootTest
        @ActiveProfiles("test")
        class JobApplicationFlowTest {

            @Autowired
            private MockMvc mockMvc;

            @Test
            void candidateCanApplyForOpenJob()
                    throws Exception {

                mockMvc.perform(
                    post("/api/jobs/100/applications")
                        .contentType("application/json")
                        .content("""
                            {
                              "candidateId": 50
                            }
                        """)
                )
                .andExpect(status().isCreated());
            }
        }

Hands-on challenge

Create one complete application-flow integration test and separate it from unit tests.

Quick check

Which statement is correct?

02 What is MockMvc?

Solution and explanation

Solution:

MockMvc allows testing Spring MVC endpoints without starting a real external web server.

Suppose:

GET /api/jobs

The test can verify:

HTTP status
JSON structure
headers
authentication
validation
controller behavior

Example:

Expected:

200 OK

and:

content = array

For validation:

POST /api/jobs

with missing title.

Expected:

400 Bad Request

For unauthorized access:

DELETE /api/jobs/100

Expected:

401 or 403 depending on authentication state and authorization rules.

MockMvc is therefore useful for testing the HTTP/controller layer.

Run this example

        mockMvc.perform(
                get("/api/jobs")
                    .param("location", "Ludhiana")
                    .param("page", "0")
        )
        .andExpect(status().isOk())
        .andExpect(
            jsonPath("$.content").isArray()
        );

        mockMvc.perform(
                post("/api/jobs")
                    .contentType("application/json")
                    .content("""
                        {
                            "title": ""
                        }
                    """)
        )
        .andExpect(status().isBadRequest());

Hands-on challenge

Test successful job search, invalid job creation and unauthorized access using MockMvc.

Quick check

Which statement is correct?