Unit testing in general

Transcript

1. Unit testing in general
2. “Is a method of assessing the functionality of a software program.” Software testing
4. Test Case Input Test Case Output Black box testing App
5. Test Case Input Test Case Output White box testing
6. Cost Maintaining Testing Pyramid http://martinfowler.com/bliki/TestPyramid.html # of tests
7. Unit test Units are tested to determine if they are fit for use.
8. In a nutshell public function testArrayPush() { $stack = array(); array_push($stack, 'foo'); $this->assertEquals('foo', $stack[0]); } Precondition Execution Assertion
9. a single check that always evaluates to true or false Assertion
10. Unit? Unit is a class. (in OOP)
11. Single class Related classes Related methods Unit?
12. Unit? “really it's a situational thing - the team decides what makes sense to be a unit” - Martin Fowler
13. Unit tests Why should I care?
14. Fundamental to regression testing Required for refactoring Can be a good documentation Finds problems early Unit tests / Pros
15. Gives confidence Reduces the cost of change Improves design Unit tests / Pros
16. We have to write the tests Maintaining Unit tests / Cons
17. Hard-coded dependencies Static method calls Methods with too many responsibilities Tight coupling Complex methods Unreadable code “Untestable” code
18. Hard-coded dependencies public function doSomething() { $bar = new Bar; $bar->doSomethingElse(); }
19. Static method calls class Foo { public static function doSomething() { return static::helper(); } public static function helper() { return 'foo'; } }
21. Hard-coded dependencies public function doSomething() { $bar = new Bar; $bar->doSomethingElse(); }
22. Hard-coded dependencies protected function newCallback($className) { switch ($className) { case 'Bar': return 'BarMock'; default: return $className; } } set_new_overload(array($this, 'newCallback')); http://sebastian-bergmann.de/archives/885-Stubbing-Hard-Coded-Dependencies.html
23. Static method calls class Foo { public static function doSomething() { return static::helper(); } public static function helper() { return 'foo'; } }
24. Static method calls $class = $this->getMockClass( 'Foo', # class to mock array('helper') # methods to mock ); $class::staticExpects($this->any()) ->method('helper') ->will($this->returnValue('bar')); https://sebastian-bergmann.de/archives/883-Stubbing-and-Mocking-Static-Methods.html
25. !
26. “Just Because You Can, Does Not Mean You Should”
28. Use dependency injection Try to avoid static method calls SRP Readable KISS, DRY, SOLID Testable code
29. Hard-coded dependencies public function doSomething() { $bar = new Bar; $bar->doSomethingElse(); }
30. Dependency Injection public function doSomething(Bar $bar) { $bar->doSomethingElse(); }
31. Unit tests are first class citizens
32. Fast Isolated Repeatable Self-verifying Timely Unit tests should be FIRST
33. File system Database API call from each other Isolated?
34. Mock your dependencies “…mock objects are simulated objects that mimic the behavior of real objects in controlled ways”
37. What code should be tested? We should test the public API (of a unit)
38. Protected/Private methods? Getters and Setters? Trivial code? Exceptions? What code should be tested?
39. Selective unit testing http://blog.stevensanderson.com/2009/11/04/selective-unit-testing-costs-and-benefits/
40. Code coverage
41. Code coverage http://martinfowler.com/bliki/TestCoverage.html
42. Code coverage CRAP Change Risk Analysis and Predictions
43. Code coverage 100% 80% 50% Low Medium High
44. Automation CI Watchman IDE
45. Thank you!