My slides from ISTA 2018

1. HINDSIGHT
LESSONS
ABOUT API
TESTING
By Viktor Slavchev
Siteground
Blog: mrslavchev.com
Twitter: @TheTestingTroll

2. Agenda
• WTF is an API?
• Why would you automate an API?
• Serious cognitive barriers
• What tests worth automating
• Setup and environment
• The framework

3. Warning!!! Tools don’t make
software
Nor do they test it…

4. Bullshit warning!
I commit to:
• Not giving you a “how to”
• No 30 mins introduction
• No “live coding misery”
• No “best practices”

5. Who am I: Viktor Slavchev
• Software tester, speaker and
teacher in testing
• Blog: mrslavchev.com
• @thetestingtroll
• Insert random brag about my
achievements
• This slide is bullshit
• Nobody reads this far

6. WTF is a web service?

7. Imagine a waiter…
• You make an order
(request)
• You get a response (status
code)
• You get what you ordered
(data, result)

8. HTTP status codes – represented
by HTTP status cats

9. HTTP status codes – represented
by HTTP status cats

10. HTTP status codes – represented
by HTTP status cats

11. HTTP status codes – represented
by HTTP status cats

12. HTTP status codes – represented
by HTTP status cats

13. Method correspondence with
CRUD

14. Why testing via the API?
Why not something that clicks?!

15. Few (un)obvious reasons to
automate via API
• Clear definitive response
• Close to client
• Good failure visibility
• Easy to test with code
Source: Models of automation

16. Speaking of pyramids…
The automation iceberg

17. Setup, tech stack, context
• Restful API written in Php
• ReactJS front-end
• Docker compose – test env
• Codeception – testing tool
• Custom tools to produce data

18. Before we even think of testing
Few important notes

19. Cognitive barriers
Few things to have in mind:
• The doc is not the product
• Your coding skills will hold you
back
• The need to explore
• Tests that pass vs. tests that test

20. What tests are worth automating?
… but first – what bugs do we care
testing for?
• Service returning wrong response code
• Throwing 500
• Returning wrong data
• No data at all
• Interaction problems

21. What test are worth automating?
• Status code checks
• Structure checks
• Scenario checks

22. Status code checks
Example:

23. Status code checks – pros and cons
Pros:
•Fast and easy
• Very definitive
• Work as sanity/smoke
checks
Cons:
•Very shallow level
•GET methods
•They don’t expose
serious problems

24. Structure checks
Example:

25. Structure checks – pros and cons
Pros:
•Verify data
• Can be very specific
• Can use regex
(Codecept)
Cons:
•Useful for content only
•Suck with variable data
•Suck with deep
nesting/long responses

26. Scenario checks

27. Scenario checks – pros and cons
Pros:
• Closest to client
interaction
• Expose integration
problems
• Can be used as shallow
regression suite
Cons:
•Slow to run/develop
•Require better
abstraction
•Hard to say when it is
too much

28. Setup of the framework

29. Make it yourself

30. Few ideas that worked for me
“Worst” practices

31. Incorporate OOP principles
• Inheritance
• Reuse
• KISS
• Horizontal inheritance(traits)

32. One simple inheritance schema

33. Before method inheritance

34. Let your framework mature
• Your framework will suck at first
• It will improve incrementally
• It can’t be done in the beginning

35. Splitting logic of the test and logic of
the app
• Move common actions to base
classes
• Move common prerequisites to
setup methods
• Build inheritance trees
• Reuse rather than repeat

36. Useful resources
• Hindsight lessons about API testing
• Automating and Testing a REST API – book by
Alan Richardson
• This article by Smart Bear
• Service virtualization by Bas Dijkstra free e-book
• Your brain!!!

37. Thank you!
Questions?
mrslavchev.com
@TheTestingTroll
LinkedIn
All hail The Testing
Troll!