guide spring testing

Table of Contents

• Testing
  • Implementation
    • Module Test
    • Subsystem Test
  • Configuration
    • Configure Test Specific Beans

Testing

Implementation

Module Test

In devon4j you can extend the abstract class ModuleTest to basically get access to assertions. In order to test classes embedded in dependencies and external services one needs to provide mocks for that. As the technology stack recommends we use the Mockito framework to offer this functionality. The following example shows how to implement Mockito into a JUnit test.

import static org.mockito.Mockito.when;
import static org.mockito.Mockito.mock;
...

public class StaffmanagementImplTest extends ModuleTest {
  @Rule
  public MockitoRule rule = MockitoJUnit.rule();

  @Test
  public void testFindStaffMember() {
  ...}
}

Note that the test class does not use the @SpringApplicationConfiguration annotation. In a module test one does not use the whole application. The JUnit rule is the best solution to use in order to get all needed functionality of Mockito. Static imports are a convenient option to enhance readability within Mockito tests. You can define mocks with the @Mock annotation or the mock(*.class) call. To inject the mocked objects into your class under test you can use the @InjectMocks annotation. This automatically uses the setters of StaffmanagementImpl to inject the defined mocks into the class under test (CUT) when there is a setter available. In this case the beanMapper and the staffMemberDao are injected. Of course it is possible to do this manually if you need more control.

  @Mock
  private BeanMapper beanMapper;
  @Mock
  private StaffMemberEntity staffMemberEntity;
  @Mock
  private StaffMemberEto staffMemberEto;
  @Mock
  private StaffMemberDao staffMemberDao;
  @InjectMocks
  StaffmanagementImpl staffmanagementImpl = new StaffmanagementImpl();

The mocked objects do not provide any functionality at the time being. To define what happens on a method call on a mocked dependency in the CUT one can use when(condition).thenReturn(result). In this case we want to test findStaffMember(Long id) in the StaffmanagementImpl.

public StaffMemberEto findStaffMember(Long id) {
  return getBeanMapper().map(getStaffMemberDao().find(id), StaffMemberEto.class);
}

In this simple example one has to stub two calls on the CUT as you can see below. For example the method call of the CUT staffMemberDao.find(id) is stubbed for returning a mock object staffMemberEntity that is also defined as mock.

Subsystem Test

devon4j provides a simple test infrastructure to aid with the implementation of subsystem tests. It becomes available by simply subclassing AbstractRestServiceTest.java.

//given
long id = 1L;
Class<StaffMemberEto> targetClass = StaffMemberEto.class;
when(this.staffMemberDao.find(id)).thenReturn(this.staffMemberEntity);
when(this.beanMapper.map(this.staffMemberEntity, targetClass)).thenReturn(this.staffMemberEto);

//when
StaffMemberEto resultEto = this.staffmanagementImpl.findStaffMember(id);

//then
assertThat(resultEto).isNotNull();
assertThat(resultEto).isEqualTo(this.staffMemberEto);

After the test method call one can verify the expected results. Mockito can check whether a mocked method call was indeed called. This can be done using Mockito verify. Note that it does not generate any value if you check for method calls that are needed to reach the asserted result anyway. Call verification can be useful e.g. when you want to assure that statistics are written out without actually testing them.

Configuration

Configure Test Specific Beans

Sometimes it can become handy to provide other or differently configured bean implementations via CDI than those available in production. For example, when creating beans using @Bean-annotated methods they are usually configured within those methods. WebSecurityBeansConfig shows an example of such methods.

@Configuration
public class WebSecurityBeansConfig {
  //...
  @Bean
  public AccessControlSchemaProvider accessControlSchemaProvider() {
    // actually no additional configuration is shown here
    return new AccessControlSchemaProviderImpl();
  }
  //...
}

AccessControlSchemaProvider allows to programmatically access data defined in some XML file, e.g. access-control-schema.xml. Now, one can imagine that it would be helpful if AccessControlSchemaProvider would point to some other file than the default within a test class. That file could provide content that differs from the default. The question is: how can I change resource path of AccessControlSchemaProviderImpl within a test?

One very helpful solution is to use static inner classes. Static inner classes can contain @Bean -annotated methods, and by placing them in the classes parameter in @SpringBootTest(classes = { /* place class here*/ }) annotation the beans returned by these methods are placed in the application context during test execution. Combining this feature with inheritance allows to override methods defined in other configuration classes as shown in the following listing where TempWebSecurityConfig extends WebSecurityBeansConfig. This relationship allows to override public AccessControlSchemaProvider accessControlSchemaProvider(). Here we are able to configure the instance of type AccessControlSchemaProviderImpl before returning it (and, of course, we could also have used a completely different implementation of the AccessControlSchemaProvider interface). By overriding the method the implementation of the super class is ignored, hence, only the new implementation is called at runtime. Other methods defined in WebSecurityBeansConfig which are not overridden by the subclass are still dispatched to WebSecurityBeansConfig.

//... Other testing related annotations
@SpringBootTest(classes = { TempWebSecurityConfig.class })
public class SomeTestClass {

  public static class TempWebSecurityConfig extends WebSecurityBeansConfig {

    @Override
    @Bean
    public AccessControlSchemaProvider accessControlSchemaProvider() {

      ClassPathResource resource = new ClassPathResource(locationPrefix + "access-control-schema3.xml");
      AccessControlSchemaProviderImpl accessControlSchemaProvider = new AccessControlSchemaProviderImpl();
      accessControlSchemaProvider.setAccessControlSchema(resource);
      return accessControlSchemaProvider;
    }
  }
}

The following chapter of the Spring framework documentation explains issue, but uses a slightly different way to obtain the configuration.