Testing: A Philosophical Retrospective

The coders write the code, and then the testers write the tests: it’s not often that such an obvious idea harbors so many misconceptions. What assumptions underlie that idea? And what happens when we critically examine those assumptions?

Then our notion of software development changes dramatically. In this session, I look back at the changing ways in which my scrum team has developed and tested software over the past few years. – Who tests? How? When? And most importantly: why? In all these areas, we have (had to) revise persistent assumptions.

By the end of this session, you will be aware of some ingrained patterns in the way agile teams develop and test software. A solid understanding of the role of testing will shed new light on the responsibilities of developers and testers, and enable you to take the first step towards improvement.

Transcript

1. Testing A Philosophical Retrospective Karl van Heijster www.karlvanheijster.com
2. When a team changes its development process…
3. …it pays to check whether its presuppositions still hold
4. What did our changing testing strategy teach us about testing?
5. Our original development process was deceptively simple:
6. The programmers program a feature, the testers test it
7. This presupposed a lot about 1) how 2) who 3) when, and 4) why we tested software
8. We saw testing as 1) a manual task 2) done by testers 3) after coding 4) to check the dev’s work
9. Problem Our way of working lead to week long regression test sprints
10. Solution Automate the test scripts
11. We became aware of some (now) incorrect presuppositions
12. Good tests are 1) automated 4) to prevent regressions
13. Problem The tester could not keep up with the work
14. Solution Make the programmers (partly) responsible for automating tests
15. This made us notice some other incorrect presuppositions
16. Tests are written 2) by testers and programmers 4) to document the code
17. Problem Programmers started skipping the tests
18. Solution Teach them the ways of Test-Driven Development
19. Again: examine your presuppositions
20. Testing is something you do 3) during development 4) to help you design the code
21. The development of our testing strategy shows the following trends:
22. o Automate ever more o Test ever sooner o Shift responsibility
23. Programming and testing are two sides of the same coin
24. Where to go from here?
25. Problem Programmers and testers are doing redundant work
26. Solution Collaborate!
27. The role of the tester changes from “code cop” to sparring partner
28. But that won’t be the last presupposition that will have to go…
29. The unexamined life is not worth living - Socrates
30. Testing A Philosophical Retrospective Karl van Heijster www.karlvanheijster.com