Unittest discovery silently fails when Pytest is not installed

[joyceerhl]

Testing #13301

1. Run Python: Configure Tests
2. Choose unittest
3. 🐛 nothing happens. When I open the test view I see that there was a discovery error and that I should see Output > Python. I would expect an error message with a link or button to open the output channel
4. 🐛 the output channel says test discovery failed because pytest wasn't installed. Should we help the user install pytest in this flow? Also, is it expected that pytest is required even if I'm trying to use unittest?

[eleanorjboyd]

realized this is likely the fix: #21726

[roblourens]

I ran into this as well, so if you were expecting it to be fixed, I don't think it is.

I was also curious why pytest is used to do discovery for unittest? It just knows about everything?

[eleanorjboyd]

pytest should not be needed if you are just using unittest, will investigate and put in a fix!

[eleanorjboyd]

@roblourens, testing this and unable to reproduce the behavior. Could you send over the test file you had loaded and the settings you picked (when configuring testing so it might look something like below)

{
  "python.testing.unittestArgs": ["-v", "-s", ".", "-p", "*test*.py"],
  "python.testing.pytestEnabled": false,
  "python.testing.unittestEnabled": true
}

[github-actions]

Because we have not heard back with the information we requested, we are closing this issue for now. If you are able to provide the info later on, then we will be happy to re-open this issue to pick up where we left off.

Happy Coding!

[rzhao271]

Repro steps

1. My potentially irrelevant user settings:

"python.experiments.optInto": [
	"pythonTestAdapter"
],
"python.terminal.executeInFileDir": true,
"python.createEnvironment.trigger": "prompt",

2. Navigate to a directory on Windows Terminal (pwsh profile)
3. Run the following lines

mkdir example-python-tests
cd example-python-tests
ni sample.py
ni test_sample.py
mkdir .vscode
ni .vscode/settings.json
code-insiders .

3. VS Code Insiders should be open now. Create a new venv Python environment and confirm that pytest isn't installed in the venv

4. Copy the following to sample.py

def xyz():
    return 0

5. Copy the following to test_sample.py

import unittest

class TestScratch(unittest.TestCase):
    def test_add(self):
        pass

6. Copy the following to .vscode/settings.json

{
    "python.testing.unittestArgs": [
	"-v",
	"-s",
        ".",
        "-p",
        "test_*.py"
    ],
    "python.testing.pytestEnabled": false,
    "python.testing.unittestEnabled": true
}

7. Click on the beaker icon in the activity bar to go to the tests view
8. 🐛 pytest Discovery error is shown

[eleanorjboyd]

hm tried these steps and still not seeing it, will keep my eye out as I have seen this before but also couldn't repro it a second time.