This document discusses mocks and the Mockito API for creating mocks in tests. It defines mocks as objects that simulate the behavior of real objects. Mocks are useful for avoiding high coupling, promoting high cohesion, and improving test performance. The document then covers the Mockito API in particular, noting that it is easy to use, has excellent documentation, and separates stubbing from verification. Examples are provided of Mockito features like exception handling with matchers. The conclusion recommends Mockito for improving test quality.

1. Mocks with Mockito API
Camilo Lopes
www.camilolopes.com

2. Agenda
• About Mocks
• Mocks API
• Mockito API
• Mocks with Mockito
• Conclusion

3. What Mock is?

4. In one setence
“Mocks are object that simulates
the behavior of real an object.”

5. Why Mocks?
• Help design solution;
• Avoid high coupling;
• Promove high cohesion;
• Easy to use;
• Promove Agile development;
• Improve performance in unit test;

6. Where can I use Mock?
• DataBase;
• WebServices;
• NetWork
• Classes;

7. How to use Mock?

8. Mocks API

9. What is the best?

10. In my opinion is...

11. Why?

12. Because...

13. Mockito API
• Easy to use;
• High learning Curve;
• Excellent Documentation;
• “stub-run-verify” concept;
• Concept stub is separed of verification;
• Clear code;

14. And the others?
• Use “except-run-verify” concept; (it is not good)
• Code is not as clear as Mockito;
• Documentation is not as good as Mockito ‘s doc;
• Verify and expect are bult-in in expect() method;
(Mockito is separated. It is better)

15. Mockito Features
Examples ahead

16. Exception
when(myobjectMock.buy(new BigDecimal("-5000.00"))).thenThrow(new
Exception());

17. Matchers
when(myobjectMock.buy(any(BigDecimal.class)).thenReturn(true);
Note
Mockito offers some built-in such as: anyString,
anyInt(), any(class). But we can create
customized built-in. Our class must extends
ArgumentMatcher.

18. void method
• doAnswer, doNothing, doThrow or doReturn
doThrow(new Exception()).when(mockObject).buy(new
BigDecimal("-5000"))

19. Verify
it possible check the number invocation of method
• atLeastOnce(), atLeast(int), atMost(int), never()
verify(mockobject,times(3)).buy(new BigDecimal("10000"))

20. More features
Check Mockito Documentation. There are many
examples.
http://docs.mockito.googlecode.com/hg/org/mockito/
Mockito.html

21. Conclusion
If you want to improve of quality in unit test use
Mock.It will contribute to design, code,
development etc.There are many APIs in
market, but the most used are: EasyMock,
Jmock and Mockito.

22. Thanks!!!!

23. References
http://code.google.com/p/mockito/
http://www.infoq.com/news/2008/06/mocks-q-of-when
http://www.easymock.org/
http://martinfowler.com/articles/mocksArentStubs.html