Unit testing with Easymock
?Download as ODP, PDF?
1 like?2,437 views
The document discusses various features of EasyMock, a Java testing framework for creating mock objects to test code in isolation, including how to create different types of mocks, define return values and argument matchers, and integrate EasyMock with the Unitils testing framework. It provides examples of using EasyMock to mock objects, define expected method calls and return values, and verify interactions for unit testing purposes.
Unit testing with Easymock
- 1. Easy testing with EasyMock (Java 5) ?rgo Ringo Aqris Software
- 2. Developer tests - big theory Why/when short feedback loop Classic vs mock testing http://martinfowler.com/articles/mocksArentStubs.html Failing legacy tests check if can be fixed; if not separate from working ones
- 3. EasyMock mock types (1) normal mocks expect ¨C replay ¨C verify @ Before public void setUp() { userDao = EasyMock. createMock (UserDao. class ); validator = new UserValidator( userDao ); } @ Test public void duplicateLoginNameIsInvalid() throws Exception { User user = ... errors = new BindException(user, "User" ); EasyMock.expect( userDao .isValidLoginName(user)).andReturn( false ); EasyMock.replay( userDao ); validator .validate(user, errors); assertTrue(errors.toString(), errors.hasErrors()); EasyMock.verify( userDao ); }
- 4. EasyMock mock types (2) strict mocks checks order of calls
- 5. useful if test contains many different or complex scenarios (bad style?) userDao = EasyMock. createStrictMock (UserDao. class );
- 6. EasyMock mock types (3) nice mocks useful if default return value is OK
- 7. Warning: are you in ¡°getting it pass¡± mode?
- 8. if cannot implement nice equals for some argument (but there is better alternative!) filterDao = createNiceMock(FilterDao. class ); //expect(filterDao.getFilterId("unique-filter-name", USER_ID)).andReturn(null); replay( filterDao ); validator.validate(filter, errors); assertFalse(errors.hasErrors()); verify( filterDao );
- 9. Argument matchers when to use if default equals based check doesn't work predefined matchers eq(X value)
- 10. aryEq(X value)
- 12. ...
- 13. Custom argument matchers useful if object equals doesn't work mockSender .send(eqMessageText( simpleMessage )); replay ( mockSender ); sender .sendAccountApprovedNotification( user , password); verify ( mockSender ); private SimpleMailMessage eqMessageText( final SimpleMailMessage expected) { EasyMock. reportMatcher ( new IArgumentMatcher() { public void appendTo(StringBuffer buffer) { } public boolean matches(Object argument) { SimpleMailMessage actual = (SimpleMailMessage) argument; assertEquals (expected.getText(), actual.getText()); assertEquals (expected.getSubject(), actual.getSubject()); assertEquals (expected.getFrom(), actual.getFrom()); assertEquals (expected.getTo()[0], actual.getTo()[0]); return true ; } }); return expected; }
- 14. D efine answer at runtime IAnwer interface @Test public void showErrorsOnPage1() throws Exception { StepHandler stepHandler = createMock(StepHandler.class); ... stepHandler.validate( eq ( step0 .getModel()), (Errors) notNull ()); expectLastCall ().andAnswer( new IAnswer<Object>() { public Object answer() { Errors errors = ((Errors) getCurrentArguments ()[1]); errors.reject( "Error occurred in one step" ); return null ; } }); replay (stepHandler); ... verify (stepHandler); }
- 15. EasyMock more exotic stuff for implementing stubs asStub() / asStubReturn()
- 16. asStubAnswer mock only some methods createMock(Class<T>, Method[])
- 17. EasyMock meets Unitils import static org.unitils.easymock.EasyMockUnitils.*; public class MockingTest extends UnitilsJUnit4 { @Mock private UserDao userDao ; @ Before public void setUp() { //userDao = createMock (UserDao. class ); validator = new UserValidator( userDao ); } @ Test public void duplicateLoginNameIsInvalid() throws Exception { User user = ... errors = new BindException(user, "User" ); expect( userDao .isValidLoginName(user)).andReturn( false ); //replay(userDao); replay (); validator .validate(user, errors); assertTrue(errors.toString(), errors.hasErrors()); //verify(userDao); verify (); } } http://www.unitils.org/
Editor's Notes
- #4: Good practice is to assign mock object to field and create it inside setup method. Where to put verify?
- #5: Usually not very useful since we don't care about the order. Even if order is important test mostly fails anyway if wrong order of calls.
- #6: Does not care about input arguments. Returns default values. Works if you have no expects.
- #7: One cotcha ¨C if using arg matcher for one argument must also use for others