Conclusions and recommendations

The basics

Learn one test framework well enough for basics
- Explore and use the good tools that exist out there
- An incomplete list of testing frameworks can be found in the Quick Reference
Start with some basics
- Some simple thing that test all parts
Automate tests
- Faster feedback and reduce the number of surprises

Strike a healthy balance between unit tests and integration tests
As the code gets larger and the chance of undetected bugs increases, tests should increase
When adding new functionality, also add tests
When you discover and fix a bug, also commit a test against this bug
Use code coverage analysis to identify untested or unused code
If you make your code easier to test, it becomes more modular

You probably won’t do everything perfectly when you start off… But what are some of the easy starting points?

Do you have some single functions that are easy to test, but hard to verify just by looking at them? Add unit tests.
Do you have data analysis or simulation of some sort? Make an end-to-end test with sample data, or sample parameters. This is useful as an example anyway.
A local testing framework + GitHub actions is very easy! And works well in the background - you do whatever you want and get an email if you break things. It’s actually pretty freeing.