You should see if your language has a property-based testing library; it'll have a ton of useful functionality to help with what you're already doing!

A clarification on terminology, the "property" in "property-based testing" refers to properties that code under test is supposed to obey. For example, in the author's Example 2, the collection being sorted is the property that the test is checking.

Forgive me if I’m just reading this incorrectly, but that doesn’t sound exactly like property testing as I’ve done it. the libraries implement an algorithm for narrowing down to the simplest reproducer for a given failure mode, so all of the inputs to a test that are randomized are provided by the library.

How did you deal with reproducibility when your tests use randomized data? Do you run with a random seed or something, so you can reproduce failures when they come up?

ScalaCheck includes the random seed in its failure messages, so it's easy to pull the seed out of CI/CD logs and reproduce the failure deterministically.