A no shrink setting.

[Eh2406]

Some context: As you know, I am working on a complicated strategy with slow tests associated with it. This means that shrinking takes a long time (several hours), and that when we speed up shrinking we just make things more complicated to match. A better strategy may fix this situation (suggestions welcome), but that is the context I am coming from.

Currently if the tests pass it takes ~1 min to run, but if it fails then all we get on CI is a time out.

No output has been received in the last 10m0s, this potentially indicates a stalled build or something wrong with the build itself.

I wonder whether we could have an opt in setting for the proptest macro that would skip shrinking and just print the seed. The idea is that CI could run the test in this fail-fast mode, then if we want to shrink the example that CI found we could put the seed in the local regressions file.

[Centril]

(There is a .no_shrink() method on Strategy that you can use for this locally.)

[Eh2406]

There is a work around, and the more I think about this the less it makes sense as having first class support. It would be nice to see what seed failed the CI run, but it is not going to be easy to figure out what to do with it, like which file to add it too.

[AltSysrq]

As of 0.8.7, there's now also max_shrink_time and max_shrink_iters options (PROPTEST_MAX_SHRINK_TIME / PROPTEST_MAX_SHRINK_ITERS env vars) to control this on a per-test basis or at run time.