Tests Unitaires
Configuration
In JUnit 5, the @RunWith annotation has been replaced by the more powerful @ExtendWith annotation.
Before & After
@Before @After
The method with this annotation is executed before or after every test method
@BeforeClass @AfterClass
The method with this annotation is executed before or after every test class
Parametrize Test
- On top of the test class @RunWith(Parameterized.class)
- method annotated with @Parameter is passing Arrays.asList()
Mockito
Mocks vs Stubs = Behavioral testing vs State testing
Mockito does not allow Stubbid final & Private methods
Stubbing
Empty class, only return the expected
- cannot be dinamically created from code
<source lang="Java"> MyMockedService myMockedService = new MyMockedService(); stub(myMockedService.methodToTest("param")).return("value"); </source>
Test lifecycle with stubs:
- Setup - Prepare object that is being tested and its stubs collaborators.
- Exercise - Test the functionality.
- Verify state - Use asserts to check object's state.
- Teardown - Clean up resources.
Stubbing Variations
- Argument Matchers
Spy
A Spy is a Stub than is also collecting informations during the test
Used on legacy system where you don't really have access to the code or dependencies
- How many times this method is called ?
- Is this method is called at least once ?
Mock
Fullclass with implementation, same comportement as in real code.
- Creating Objects that simulate the behavior of real objects
- can be dynamically created from code - at runtime
- offer more fonctionnalities than stubbing
- How many times this method is called ?
- Is this method is called at least once ?
<source lang="Java"> MyMockedService myMockedService = mock(MyMockService.class); when(myMockedService.methodToTest("param")).thenReturn("value"); </source>
Test lifecycle with mocks
- Setup data - Prepare object that is being tested.
- Setup expectations - Prepare expectations in mock that is being used by primary object.
- Exercise - Test the functionality.
- Verify expectations - Verify that correct methods has been invoked in mock.
- Verify state - Use asserts to check object's state.
- Teardown - Clean up resources.
Argument Matchers
Mockito extends Matchers and theses methods are available
- any()
- anyString()
- anyList()
- ...
Exceptions
<source lang="Java"> //To prevent from failing when an exception is thrown @Test(expected=RuntimeException.class) </source>
Annotations
@Mock
Mockito automatically creates a Mock of this class needs @RunWith(MockitoJunitRunner.class)
@InjectMocks
<source lang="Java"> // Every time we use TodoBusinessImpl we want to inject todoServiceMock @Mock TodoService todoServiceMock; when(todoServiceMock.retrieveTodos("dummy"))).thenReturn(todos); // todoServiceMock is injected as a constructor parameter TodoBusinessImpl todoBusinessImpl = new TodoBusinessImpl(todoServiceMock) </source> Instead of previous code, mockito can help <source lang="Java"> // Every time we use TodoBusinessImpl we want to inject todoServiceMock @Mock TodoService todoServiceMock; @InjectMocks TodoBusinessImpl todoBusinessImpl ; when(todoServiceMock.retrieveTodos("dummy"))).thenReturn(todos); // Replaced with Injected // MocksTodoBusinessImpl todoBusinessImpl = new TodoBusinessImpl(todoServiceMock) </source>
@Captor
<source lang="Java"> //@Captor ArgumentCaptor .. lets see later </source>
@MockBean
Spring Mock Bean