Unit Testing: What? Why? How?

Slides from my talk at WP Hooked, February 2017.

https://www.meetup.com/wp_hooked/

Transcript

1. Unit Testing: What? Why? How?
2. John Blackbourn WordPress core developer Working with WordPress for 10+ years Senior Engineer at Human Made @johnbillion
3. Unit Testing: What? Why? How?
4. You’re Going to L VE Unit Testing
5. That’s Enough of That
6. Unit Testing: What? Why? How?
7. A unit test is a piece of code which exists only to verify expectations about the behaviour of another piece of code Verification
8. a.k.a. “Does my function do what I expect it to do?”
9. A unit test operates in isolation in order to avoid external interference Isolated
10. Tests typically run on the command line CLI
11. Tests are highly efficient because they're quickly repeatable Automated
12. Crossing your fingers and hoping… is not a unit test
13. Unit Testing: What? Why? How?
14. A unit test can cover many scenarios and never misses anything Accuracy
15. Unit tests give you increased assurance that changes are less likely to cause breakage Assurance
16. Unit tests give you confidence to make changes Confidence
17. Unit tests help you write better code Smaller functions Separation of concerns Quality
18. Unit tests can be liberating Clarity
19. Unit Testing: What? Why? How?
24. “But I know that false isn’t true”
26. Arrange Act Assert AAA
27. Each time a WordPress test runs, it operates on a fresh installation Remember
32. Accuracy Assurance Confidence Quality?… The Result
33. Assertions assertTrue( $actual ) assertFalse( $actual ) assertEquals( $expected, $actual ) assertCount( $expected, $actual ) assertObjectHasAttribute( $key, $actual ) assertArrayHasKey( $key, $actual ) assertWPError( $actual ) assertCanonical( $actual, $expected )
34. a.k.a. A Real World Gotcha Type Juggling Kills Me
37. WUT
39. Provide Verification Isolated Automated Recap
40. Accuracy Assurance Confidence Quality Recap
41. Arrange Act Assert Recap
42. I Hope You’ll Fall In L VE With Testing
43. Read the WordPress Unit Tests Visit PHPUnit website for reference Check out WP-CLI scaffolding What Next?
44. John Blackbourn @johnbillion