Devday2016 real unittestingwithmockframework-phatvu
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This document discusses real unit testing and the use of mock frameworks. It provides an introduction to unit testing and why it is important. It explains that real unit testing involves mocking dependencies so that units can be tested in isolation without concerning dependencies. The document then discusses mock objects and frameworks like Mockito that allow creating mock dependencies. It provides examples of how to use Mockito to mock dependencies and test units without their implementation. It also covers some Mockito features and limitations as well as best practices for unit testing.
Devday2016 real unittestingwithmockframework-phatvu
- 1. REAL UNIT TESTING WITH MOCK FRAMEWORK THEORY & PRACTICE PHAT VU
- 2. CONTENTS 1. About me 2. Unit testing refresh 3. Real unit testing 4. Mock framework 5. Mockito • Introduction • Practice / gotcha 6. Wrapping up 7. Q&A
- 3. GOALS • What real Unit testing is, its importance • Mock objects • How you can write a real unit testing
- 4. My DNA
- 5. My DNA
- 6. My DNA Vũ Hồng Phát Software Engineer, 05 years Java, Database, Open-source Interested in • Programming • Agile/Scrum • High quality software development • Optimization • Testing [email protected] phatvu.dng
- 8. • Do you know what unit testing is? • Do you think it’s important? • Who will write it? • Do you enjoy when writing it? CHECK IN
- 9. Unit testing is a software development process in which the smallesttestable parts of an application, called units, are individually and independently scrutinized for proper operation. Unit testing is often automated but it can also be done manually. WHAT http://searchsoftwarequality.techtarget.com/definition/unit-testing
- 12. WHY 1. Prove that your code actually works. 2. Form of sample code / documentation 3. Code refactoring 4. Forces you to plan before you code • Better design • Testable code 5. Integrate with Continuous Integration 6. It’s more fun to code with them than without
- 13. UNIT TEST FIRST? Problem (Unit testing) Solution (Implementation)
- 14. TDD (TEST-DRIVEN DEVELOPMENT) https://goo.gl/S7iDxk
- 15. A SIMPLE PROBLEM Implement a service that accept 2 integer numbers, then return summary of them Example: Input : 1 and 2 Output : 3
- 16. Write unit test first
- 17. Then, implement Run the unit test
- 19. DEPENDENCIES • A tested object usually talks to other objects known as collaborators / dependencies • These dependencies need to be created, so the tested object can be assigned to them in the test • Any hello world has no dependencies on outside classes • In the real world, software has dependencies MathService Calculator
- 20. DEPENDENCIES
- 21. REAL UNIT TESTING • The idea of unit testing is that we want to test our code without testing the dependencies • Unit testing verifies that the code being tested works, regardless of it's dependencies • Be able to test the code, no matter dependencies implementation • If the code I write works as designed and my dependencies work as designed, then they should work together as designed
- 22. EXAMPLE MathService has dependency : Calculator When testing MathService: • Do not test Services and Repositories layers. Assume they has been tested and works as designed • Do not wait for their implementation MathService Calculator MathService Calculator
- 24. MOCK OBJECT In OOP, mock objects are simulated objects that mimic the behavior of real objects in controlled ways. https://en.w ikipedia.org/wiki/Mock_object
- 25. CRASH TEST DUMMY https://en.w ikipedia.org/wiki/Crash_test_dummy
- 26. GIVEN – WHEN - THEN Style of representing tests, part of BDD • Given defines the preconditions that hold before an event or operation • When identifies an event or operation • Then identities the post conditions that hold after the event or operation
- 27. GIVEN – WHEN - THEN • Given : the Login page is opening • When : I enter a correct user name & password, then click on Login button • Then : I am on the Home page
- 29. MOCKITO Is a mocking framework helpful in creating mocks and spies in a simple and intuitive way, while at the same time providing great control of the whole process “Really cleans up the unit test by not requiring expectations. Personally, I much prefer the Mockito API to the EasyMock API for that reason” - Hamlet D'Arcy https://code.google.com/archive/p/mockito/wikis/Quotes.wiki
- 31. STATIC IMPORTS
- 32. GETTING STARTED How can I test MathService.add() without concern on its dependency (Calculator implementation) ? I have to simulate Calculator as a mock object
- 33. GETTING STARTED @Mock - create a mock object must initialize this object with a MockitoAnnotations.initMocks(this) method call @InjectMocks - injects mocks into tested object automatically BDDMockito.java given(….).willReturn(….)
- 37. THAT’S QUITE ENOUGH. LET’S DRINK
- 39. ARGUMENT MATCHERS Mockito provides a set of build-in matchers, such as: anyInt(), anyString() If you are using argument matchers, all arguments have to be provided by matchers
- 42. MULTIPLE CALLS Return different values for subsequent calls of the same method
- 43. SPY • A mock created as a proxy to an existing real object • Some methods can be stubbed • Some ones invoked in real • Partial mocking • Usually there is no reason (code smell) to spy on real objects
- 44. SPY
- 45. LIMITATIONS Mockito can not: • mock final classes • mock enums • mock final methods • mock static methods • mock private methods • mock hashCode() and equals() PowerMock or JMockit can be used to work with code that cannot be mocked with pure Mockito
- 46. GOTCHA
- 49. TEST COVERAGE A measurement of how many lines/blocks of your code are executed while the automated tests are running A useful tool for finding untested parts of a codebase 100% - it would smell of someone writing tests to make the coverage numbers happy, but not thinking about what they are doing Low coverage numbers, are a sign of trouble. But high numbers don't necessarily mean much Upper 80s or 90s
- 51. MOCK PRIVATE METHODS Why Mockito doesn't mock private methods? (https://github.com/mockito/mockito/wiki/Mockito-And-Private-Methods)
- 52. MOCK PRIVATE METHODS Refactoring Considerations • Low cohesion (has too many responsibilities) • Extract into separate class. Workaround Using Mockito • Changing private access modifier to default • Partially mock testing object by using spy • PowerMock or JMockIt (More : https://dzone.com/articles/mock-private-method)
- 53. Unit testing is testing units Units bare without dependencies. And this can be done with mocks SAYING IT SIMPLY
- 54. Q & A