vscode-python-test-adapter: Tests do not run

I have a couple of tests set up using pytest.

When I click play they go blue with the elipsis

But then return.

This appears to be happening on both my and my co-founders computers across multiple projects and appears to have started occurring sometime during last night (everything was working at 2000 GMT on Tuesday 16th March.

I can’t see that a new version has been released, but as it is happening on multiple computers across multiple projects I assume something external has changed.

setting.json looks like:

{
    "python.pythonPath": "SOME_CONDA_ENVIROMENT",
    "python.testing.pytestArgs": [
        "remove-white-background"
    ],
    "python.testing.unittestEnabled": false,
    "python.testing.nosetestsEnabled": false,
    "python.testing.pytestEnabled": true
}

The python test adapter log appears free of errors:

2021-03-17T11:34:37.107Z INFO pytest at 'project-name': Reading configuration for workspace project-name
2021-03-17T11:34:37.108Z  DBG pytest at 'project-name': usingNewInterpreterStorage feature flag is 'true'
2021-03-17T11:34:37.108Z INFO pytest at 'project-name': Using auto-detected pythonPath SOME_CONDA_ENVIROMENT
2021-03-17T11:34:37.109Z INFO pytest at 'project-name': Running tests using python path 'SOME_CONDA_ENVIROMENT' in PROJECT_FOLDER
2021-03-17T11:34:37.109Z INFO pytest at 'project-name': Environment variables file PROJECT_FOLDER/.env does not exist
2021-03-17T11:34:37.113Z INFO pytest at 'project-name': Running pytest with arguments: --rootdir=PROJECT_FOLDER, --junitxml=/var/folders/kk/m58vb4996x10jnrg4n7kcchc0000gn/T/tmp-1272-buZvkt6qIWZI, --override-ini, junit_logging=all, --override-ini, junit_family=xunit1, folder-name
2021-03-17T11:34:37.113Z INFO pytest at 'project-name': Running pytest as a Python module
2021-03-17T11:34:42.571Z INFO pytest at 'project-name': Test execution completed

The tests run correctly with pytest .

Update

Errors can be caused to appear on uncompilable code.