how to get fast-check error reports when using jasmine with expect?

[vilanelle]

Hi all 👋

I'm looking into adopting property-based testing with the use of this excellent library and run into a small issue.

Our test runner is karma / jasmine. When using fast-check with jasmine expect (configured as per the docs example), the tests work fine, but the error reports are jasmine, not fast-check. So we miss all the valuable information from the test failure like the number of runs, property shrinking or counterexamples.

I can use return with expect().nothing() as a workaround, but this is not ideal.

Can the library be configured to use expect and still get fast-check reports?

Thanks!

[dubzzz]

Have you put the stopSpecOnExpectationFailure in your configuration of Jasmine? If you cannot, I'd recommend you to use assert instead of expect (without that flag expect will not throw and it's a per-requisite to make fast-check able to catch problems)

[dubzzz]

If the suggestion does not work and if you have a minimal repro of your problem, I'd happy to help.

[dubzzz]

I have not played with https://github.com/dubzzz/fast-check-examples/blob/main/test-jasmine/example.spec.js for a while, is it working as you expect in case of failure? If not it could be a minimal repro for me.

[vilanelle]

Hi Nicolas, many thanks for your quick response 🙇

I've tested your jasmine example and it works perfectly fine (produces proper fast-check logs).

It appears that our issue is tied to our setup: we're using karma rather than jest/mocha. So probably it's a matter of figuring out proper configs and possibly plugins.