Python test runner is extremely slow

[JP01]

Describe the feature you are requesting
Python tests (at least unittest) are slow using the Test runner. This appears to be because it runs each test individually. If I run them from command line it takes about 3 seconds to run 900 tests. Running from vscode instead takes about 3 minutes.

Reasons for requesting this feature
Tests are orders of magnitude slower to execute from vscode vs commandline.

Describe alternatives you've considered
Running tests in the command line is fine I guess, but it would be nice to have the integrated test runner work better.

[bschnurr]

do you have a code repo or sample project you can share?

[rchiodo]

This functionality is actually part of the python extension, and not pylance. Transferring.

[parched]

I see the same behaviour in our project with pytest too.

[eleanorjboyd]

Hello! Sorry for the delayed response. These issues are both likely related to our current testing infrastructure set up. We are doing a rewrite which should help with performance right now and you can follow along with major updates here: #17242. Thanks!

[JP01]

Thanks so much Eleanor!
Hopefully this can be looked at soon :)

Is this something that is accepting open contribution or is it something being worked on internally?

[eleanorjboyd]

Hi @JP01 sorry for the delay. I am currently working on it myself as my core python responsibility. You are welcome to follow along since all the PRs and issues I create relating to this work are public. The iteration plan, a pinned issue in the python repo, will have the current tasks I am hoping to get done that month.

What will be extremely helpful is once this rewrite is released into insiders we will need to test it and determine any bugs. I will post on #17242 when it is ready for testing and so subscribe to that thread and I can notify you then!

Thank you for your offer to help and your participation in open source!v