| name | spring-integration-test-wiring |
| description | Conventions for dependency injection and mocking in Spring Boot integration tests in this project. Use this whenever writing, reviewing, or refactoring integration test classes (anything annotated @SpringBootTest, or under src/test that talks to a real Spring context), especially when deciding how to wire dependencies or mock collaborators. Also consult this before adding @Autowired, @MockBean, @MockitoBean, or field injection in any test class. |
Spring Boot Integration Test Wiring for all projects with tests developed in Kotlin
Rules for how dependencies get injected and mocked in this project's integration tests. Apply these whenever creating a
new integration test class or reviewing/editing an existing one.
1. Constructor injection only — no field injection (only for Kotlin files .kt)
Integration test classes must wire their dependencies through the constructor, never through @Autowired fields.
This skill applies to all modules and submodules of the whole project. This means that all tests made in Kotlin are a
subject of this skill. Only Kotlin files, the ones with the .kt extension should be subject to this change. No other
files should be affected.
Do:
@SpringBootTest
class JeorgActionAOPLauncherExtAOPTest @Autowired constructor(
private val bonitoCatcher: BonitoCatcher,
private val codCatcher: CodCatcher
) {
}
Don't:
@SpringBootTest
class JeorgActionAOPLauncherExtAOPTest() {
@Autowired
lateinit var bonitoCatcher: BonitoCatcher
@Autowired
lateinit var codCatcher: CodCatcher;
}
Notes:
- For every file with extension .kt that ends in IT or Test, make sure that if they need
@Autowire annotated fields or
params, that they
get injected via the mentioned above @Autowired constructor pattern.
- JUnit 5 + Spring's
TestConstructor support allows constructor injection in test classes the same way it works in
production beans. If the project hasn't set spring.test.constructor.autowire.mode=all in
application-test.properties (or via @TestConstructor(autowireMode = ALL)), the constructor still needs an explicit
@Autowired annotation as shown above — include it only in the constructor and remove it from the fields, or the
injected params.
- Keep injected fields
private val.
- If a test only needs one or two collaborators, still use the constructor — don't fall back to field injection "just
for this one."
- If the
@Autowired constructor pattern is already in use, make sure that all injected params are private val, but
also remove @Autowire if they have it.
- For all beans using any of the annotations
@MockitoBean, @MockBean, @SpyBean, @MockkBean, @MockkSpyBean, or
others, and injected with lateinit, please put them with the correct annotation in the constructor as well
2. Replace initMocks with OpenMocks
Example 1
When finding this:
initMocks(testRestTemplate)
Replace with:
openMocks(testRestTemplate)
Also replace imports from import org.mockito.MockitoAnnotations.initMocks to import org.mockito.MockitoAnnotations.openMocks
3. Migrate @MockBean annotations
The annotation @MockBean is deprecated and its usage needs to be replaced by @MockitoBean
The annotation @SpyBean is deprecated and its usage needs to be replaced by @MockitoSpyBean
The above annotations should be updated in the same way following the examples bellow.
Example 1
On a class level, replace this:
@MockBean(Planet.class)
private MyService myService;
with this:
@MockitoBean(types = Planet.class)
private MyService myService;
Example 2
Replace also the usages of import org.springframework.boot.test.mock.mockito.MockBean; with import org.springframework.test.context.bean.override.mockito.MockitoBean;
Example 3
The beans that are declared are like this:
@MockBean
private BankCompanyBankRepository bankCompanyBankRepository;
should be replaced to something like:
@MockitoBean
private BankCompanyBankRepository bankCompanyBankRepository;
4. MockMvc test upgrade for Sprin Boot 4.0.0
Please add:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webmvc-test</artifactId>
<scope>test</scope>
</dependency>
as a dependency for projects that use WebMvcTest
Replace the import: import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest to org.springframework.boot.webmvc.test.autoconfigure.WebMvcTest
5. MockKBean uses different syntax in recent MockK versions
The syntax is slightly changed in the latest Spring MocK versions.
Example 1
Changes in MockKBean
Replace @MockkBean(classes = [DataSource::class]) with @MockkBean(types = [DataSource::class])
6. Test class checklist
Before submitting/reviewing an integration test class, confirm:
