@SpringBootTest for integration tests - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to annotate a test class for Spring Boot integration testing.

Spring Boot

@[1]
public class MyServiceIntegrationTest {
    // test methods here
}

Drag options to blanks, or click blank then click option'

AComponentScan

BConfiguration

CEnableAutoConfiguration

DSpringBootTest

Attempts:

3 left

💡 Hint

Common Mistakes

Using @ComponentScan instead of @SpringBootTest

Forgetting to annotate the test class

Using @Configuration which is for config classes, not tests

The @SpringBootTest annotation tells Spring Boot to look for a main configuration class and start the full application context for integration tests.

2fill in blank

medium

Complete the code to inject a service bean into the test class.

Spring Boot

@SpringBootTest
public class MyServiceIntegrationTest {

    @[1]
    private MyService myService;

    // test methods
}

Drag options to blanks, or click blank then click option'

AInjectMocks

BAutowired

CResource

DMockBean

Attempts:

3 left

💡 Hint

Common Mistakes

Using @MockBean when you want the real bean

Using @InjectMocks which is from Mockito, not Spring

Forgetting to annotate the field

The @Autowired annotation tells Spring to inject the bean from the application context into the test class.

3fill in blank

hard

Fix the error in the test method to ensure the application context loads correctly.

Spring Boot

@SpringBootTest
public class MyServiceIntegrationTest {

    @Autowired
    private MyService myService;

    @Test
    public void contextLoads() {
        [1]
    }
}

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Afail("Not implemented")

BassertTrue(false)

CassertNotNull(myService)

DSystem.out.println("Test")

Attempts:

3 left

💡 Hint

Common Mistakes

Leaving the test empty

Using fail() which always fails the test

Printing output instead of asserting

The contextLoads test should verify that the service bean is injected and not null, confirming the context started properly.

4fill in blank

hard

Fill both blanks to configure the test to run with a random port and inject the port number.

Spring Boot

@SpringBootTest(webEnvironment = [1])
public class WebIntegrationTest {

    @Value("${local.server.port}")
    private int [2];

    // test methods
}

Drag options to blanks, or click blank then click option'

ARANDOM_PORT

BDEFINED_PORT

Cport

DserverPort

Attempts:

3 left

💡 Hint

Common Mistakes

Using DEFINED_PORT which uses default port 8080

Injecting port into a field named 'port' but referencing differently

Not setting webEnvironment at all

Using webEnvironment = RANDOM_PORT starts the server on a random port. The port is injected into the serverPort field using @Value.

5fill in blank

hard

Fill all three blanks to create a test that mocks a bean and verifies it was called.

Spring Boot

@SpringBootTest
public class ServiceMockTest {

    @MockBean
    private MyRepository [1];

    @Autowired
    private MyService [2];

    @Test
    public void testServiceCall() {
        [2].performAction();
        verify([1]).save(any());
    }
}

Drag options to blanks, or click blank then click option'

AmyRepository

BmyService

Crepository

Dservice

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently

Not mocking the repository bean

Not verifying the mock interaction

The @MockBean creates a mock of MyRepository named myRepository. The service myService is autowired. The test calls myService.performAction() and verifies myRepository.save() was called.

Practice

1. What is the main purpose of using @SpringBootTest in a Spring Boot project?

easy

A. To configure database connections only

B. To mock all dependencies automatically

C. To run unit tests without loading Spring context

D. To load the full application context for integration testing

Solution

1. Step 1: Understand what @SpringBootTest does

   This annotation loads the entire Spring Boot application context, allowing tests to run with all beans and configurations loaded.

2. Step 2: Compare with other testing annotations

   Unlike unit tests or mocks, @SpringBootTest is used for integration tests that need the full app context.

3. Final Answer:

   To load the full application context for integration testing -> Option D

4. Quick Check:

   @SpringBootTest = full app context load [OK]

Hint: Remember: @SpringBootTest loads full app context for integration [OK]

Common Mistakes:

• Thinking it mocks all dependencies automatically
• Confusing it with unit test annotations
• Assuming it only configures database connections

2. Which of the following is the correct way to use @SpringBootTest to start the web environment on a random port?

easy

A. @SpringBootTest(webEnv = RANDOM_PORT)

B. @SpringBootTest(webEnvironment = "random")

C. @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)

D. @SpringBootTest(port = RANDOM_PORT)

Solution

1. Step 1: Recall the correct attribute name and value

   The attribute to set the web environment is webEnvironment, and the enum value for random port is WebEnvironment.RANDOM_PORT.

2. Step 2: Check syntax correctness

   @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT) uses the correct attribute and enum syntax. Other options use incorrect attribute names or string values.

3. Final Answer:

   @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT) -> Option C

4. Quick Check:

   Correct attribute and enum = @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT) [OK]

Hint: Use webEnvironment = WebEnvironment.RANDOM_PORT exactly [OK]

Common Mistakes:

• Using wrong attribute name like webEnv
• Passing string instead of enum
• Trying to set port directly in annotation

3. Given the following test class snippet, what will be the output when running the test?

\@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
class MyIntegrationTest {
  \@Autowired
  private TestRestTemplate restTemplate;

  \@Test
  void testHelloEndpoint() {
    String response = restTemplate.getForObject("/hello", String.class);
    System.out.println(response);
  }
}

Assuming the /hello endpoint returns "Hello, Spring!".

medium

A. Hello, Spring!

B. null

C. 404 Not Found error

D. Test fails with context load error

Solution

1. Step 1: Understand the test setup

   The test uses @SpringBootTest with RANDOM_PORT and injects TestRestTemplate, which allows calling the real HTTP endpoint.

2. Step 2: Predict the endpoint call result

   The /hello endpoint returns "Hello, Spring!" so the call will return this string and print it.

3. Final Answer:

   Hello, Spring! -> Option A

4. Quick Check:

   TestRestTemplate calls real endpoint = "Hello, Spring!" [OK]

Hint: TestRestTemplate calls real endpoint in @SpringBootTest [OK]

Common Mistakes:

• Expecting null because of missing mocks
• Assuming 404 because of wrong port
• Thinking context fails to load

4. You wrote this test but it fails with a NoSuchBeanDefinitionException for TestRestTemplate. What is the likely cause?

\@SpringBootTest
class MyTest {
  \@Autowired
  private TestRestTemplate restTemplate;

  \@Test
  void test() {
    // test code
  }
}

medium

A. TestRestTemplate is not a Spring bean

B. Missing webEnvironment setting to start web server

C. Forgot to add @Autowired annotation

D. Test class must be public

Solution

1. Step 1: Identify why TestRestTemplate bean is missing

   By default, @SpringBootTest does not start the web server unless webEnvironment is set, so TestRestTemplate bean is not created.

2. Step 2: Fix by adding webEnvironment

   Adding webEnvironment = WebEnvironment.RANDOM_PORT or DEFINED_PORT starts the server and creates the bean.

3. Final Answer:

   Missing webEnvironment setting to start web server -> Option B

4. Quick Check:

   webEnvironment needed for TestRestTemplate bean [OK]

Hint: Add webEnvironment to enable TestRestTemplate bean [OK]

Common Mistakes:

• Assuming TestRestTemplate is always available
• Forgetting to set webEnvironment in @SpringBootTest
• Thinking @Autowired is missing

5. You want to write an integration test that loads the full Spring Boot context but disables the web server startup to speed up tests. Which @SpringBootTest configuration should you use?

hard

A. @SpringBootTest(webEnvironment = WebEnvironment.NONE)

B. @SpringBootTest(webEnvironment = WebEnvironment.MOCK)

C. @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)

D. @SpringBootTest(webEnvironment = WebEnvironment.DEFINED_PORT)

Solution

1. Step 1: Understand webEnvironment options

   WebEnvironment.NONE disables web server startup but loads full context. MOCK uses mock servlet environment, RANDOM_PORT and DEFINED_PORT start real servers.

2. Step 2: Choose option that disables web server

   To speed up tests without web server, use WebEnvironment.NONE.

3. Final Answer:

   @SpringBootTest(webEnvironment = WebEnvironment.NONE) -> Option A

4. Quick Check:

   Disable web server with WebEnvironment.NONE [OK]

Hint: Use WebEnvironment.NONE to skip web server startup [OK]

Common Mistakes:

• Using MOCK which still sets up servlet environment
• Starting real server with RANDOM_PORT or DEFINED_PORT
• Confusing NONE with MOCK