Experimental debugger wont stop on breakpoints when debugging testcases in async-await code

Environment data

• VS Code version: 1.25.0
• Extension version (available under the Extensions sidebar): 2018.6.0 (20 June 2018)
• OS and version: Kubuntu 17.10, Linux 4.13.0-46
• Python version (& distribution if applicable, e.g. Anaconda): Python 3.6.3
• Type of virtual environment used (N/A | venv | virtualenv | conda | …): pipenv
• Relevant/affected Python packages and their versions: unittest, pytest, trio, asyncio

Actual behavior

Running a test on an async function running, the debugger won’t stop on breakpoints inside async functions. Tried with both unittest and pytest. Originally tested with trio event loop but the problem also occurs with asyncio, so it is not event loop specific.

It looks as if the execution stops, but you don’t get an indication at all, no yellow line on the breakpoint, no stack trace, no variable inspection and shortly after the test seems to crash.

Expected behavior

Debugger stops on breakpoint inside async function.

Steps to reproduce:

Test code using pytest:

def test_content(response):
    """Sample pytest test function with the pytest fixture as an argument."""
    # from bs4 import BeautifulSoup
    # assert 'GitHub' in BeautifulSoup(response.content).title.string
    async def test_something_async():
        assert 1 == 2

    trio.run(test_something_async)

I set the breakpoint on the assert line, like in the screenshot above.

Logs

Output from Console under the Developer Tools panel (toggle Developer Tools on under Help)

============================= test session starts ==============================
platform linux -- Python 3.6.3, pytest-3.6.3, py-1.5.4, pluggy-0.6.0
rootdir: /home/andersa/python/realtime_data, inifile: setup.cfg

collecting 1 item                                                              
collected 1 item                                                               
tests/test_realtime_data.py 

[andersea]

@DonJayamanne It works!

I would like to note here that if you are debugging a library, you won’t have a launch.json file, since it wouldn’t make sense to run a library, most of the time. All you want to do is run the unit tests, and be able to run the unit tests through the debugger.

For this use case you can edit the project settings file and add this configuration:

"python.unitTest.useExperimentalDebugger": true

Thanks for the help all!

[DonJayamanne]

@andersea Please could you test this with the latest version of the extension. Please ensure you are using the experimental debugger. All you need to do is go into the .vscode/launch.json file and change the setting from "type":"python" to "type":"pythonExperimental"