End To End Testing with Terratest

Anyone ever tested their IAC before?!, guessing no.

This talk features guidelines on how to test your Terraform code with Terratest from the start to finish to ensure those itchy state changes on your next deployment don't cause hours of heartbreaking debugging on your cloud or on-prem systems.

Transcript

1. End To End Testing With Terratest Copyright © 2019 HashiCorp
2. Bakare Emmanuel AKA Bakman !
3. Bakare Emmanuel Bakman ! Experienced Plumber @ DEIMOS fixing pipelines and other stuff
4. Bakare Emmanuel Bakman ! Experienced Plumber @ DEIMOS fixing pipelines and other stuff Failing comedian in real life
5. E2E Testing With Terratest Bakare Emmanuel bakman.build TiemmaBakare
6. Testing
8. Then one day we write a couple tests But they fail or we hack it for that prod deployment...
10. Testing is pretty simple 1 == 1
12. Until it’s not 1 != “1”
13. Until it’s not 1 != “1” Infrastructure testing is like this
14. Configurations aren’t always constant “1” != 1
15. Configurations aren’t always constant 1 != “1” dev And it doesn’t get easier with multiple environments 2 != “1” prod 3 != “12” staging
16. We configure tests to check various parts of that!
17. Hashicorp has quite some tools:
18. We’d be using these for automation:
19. Extras for the infrastructure
20. And some golang for the tests
21. Together, here’s our stack
22. Terratest Infrastructure testing library in Golang Terratest is a testing library with a set of useful modules that help make sure your infrastructure code doesn’t suck and stop working half way in production. Just like software, just because it compiles does not mean it is working. Terratest helps make sure it works. Check out the list of their supported libraries on their site: https://terratest.gruntwork.io/
23. List of the modules embedded in their go library
24. Sample test using terratest modules
25. DEMO REPO: https://github.com/tiemma/hashitalks-terratest
26. Making Great Tests
30. Start Small, like in Units
31. Guidelines Modules are your starting point, don’t write a 200 line main.tf file Resources are first class citizens like variables, you don’t test variables so why test single resources with constant parameters. You’d also have duplicate resources to test different use cases, it gets longer and longer.
33. Guidelines Unit tests should cover parts of your infrastructure that can be singly created Things like instances, AMI packages etc. Unit test the individual components that make your infrastructure.
34. Randomize configurations when testing
35. Guidelines Do not hard code your configuration like you did with your variables.tf Tests do not work the same as a deploy. Randomize your configuration, deploy in a different region without resources. Literally set yourself up for failure and see how it responds. If it passes when it should not, I’d check production if I were not testing before.
36. Separate environments
37. Guidelines Using your staging to run tests is like driving a driverless car, you’re not always in control Isolate your environments for testing, spin up new accounts and tear it down. Some tests leave resources but you can use tools like cloudnuke from gruntwork to delete other resources. Just imagine doing a cloudnuke on prod by “accident”, tragic!
39. Guidelines Don’t reuse state, implementing state locking should not be a go to plan for tests When testing, run all your configs as though you got a budding new server with that extra “vroom”. Adding in state to it just brings all the problems your tests tried to avoid.
40. Bring application and 3rd party integration tests into your infrastructure tests
41. Guidelines Keep it small but keep it reasonable Things like security audits, benchmarks, networking checks etc. Depending on how far your scale grows, you’d want to be sure you’ve got all these covered during your builds.
42. Tests don’t really catch all your errors, eventual consistency does become inconsistent but it keeps the bugs away
43. Finally, have a great time updawriting your tests
44. Thank You! hugs@hashicorp.com learn.hashicorp.com discuss.hashicorp.com 44