Property-Based Testing with PropEr, Erlang, and Elixir

Refining the Tests

We’ve got a complete rather deterministic model, with a complete piece of code to test. What we have to do now is just run tests until they fail—if they don’t, that’s a bit scary, so we should feel free to cause a failure ourselves—and then fix the problems as they come up. That step could save us from this kind of release cycle:

1. Write code.
2. Test code as usual.
3. Deploy or release the code.
4. A customer opens a ticket.
5. After scratching your head to figure out how in hell they get the problem, you finally reproduce it.
6. Fix the problem.
7. Go to 1.

Instead, we’re now more likely to have this release cycle:

1. Write code.
2. Stateful property test the code.
3. Find a problem that the framework easily reproduces for you.
4. Deploy or release the code.
5. Wait ...