[FIXED] Pytest crashes because of Flask, even when code is not using Flask

Issue

I'm currently working on a Flask application that utilizes Flask-RESTful to create an API, and it's working perfectly when I run it. However, when trying to set up tests using Pytest, I get the following error:

ImportError: cannot import name '_request_ctx_stack' from 'flask

This happens whenever I call "pytest" on the terminal. It can even be "pytest -h", it still raises the Exception.

The application works just fine when I call "py main.py". I've been testing it with Postman and a side-script I wrote using the requests package. I have never seen this error before.

By reading about the error itself I found some topics where the problem seemed to be the version of Flask. I didn't find anything specific to Pytest, though, and it doesn't seem to be my case considering the application runs as intended on it's own.

So far, I tried:

• Downgrading Flask to an earlier version;
• Removing every reference to Flask from the tests folder and trying to test a basic assert True;
• Verifying that neither Pytest nor Flask are installed globally (I've seen some suggestions that this might have been the problem);
• Recreating my virtual environment.

None of this worked so far, and I'm almost sure the problem doesn't have anything to do with my Flask installation (otherwise, the API wouldn't run, I suppose).

Solution

In my case, uninstalling pytest-flask package worked. Not sure what it does, though.

Answered By - csant