How can I get pytest to not catch exceptions

Question

When I run pytest in the vscode debugger with "Uncaught Exceptions" checked, and there are test errors, no uncaught exceptions occur, because pytest catches them d

Answer 1

The behavior is not identical but the test runner stops at the uncaught exception.

Add the file conftest.py to the directory with your tests.

# conftest.py
def pytest_exception_interact(node, call, report):
  print( call.excinfo.traceback[0] )
  pass

This adds a hook for any uncaught exceptions.

Place a break point at the line with pass.

Then Debug the test.

Look in the Debug console and you see the file and line number where the exception happened.

test_example.py F  File 'path\\test_example.py':4 in test_example
  assert False

And the debugger stops at the pass line.

You can make this hook function as fancy as you like.

Answer 2

I raised an issue with pytest and they made a suggestion that works. Add this to your conftest.py:

import os
import pytest

if os.getenv('_PYTEST_RAISE', "0") != "0":

    @pytest.hookimpl(tryfirst=True)
    def pytest_exception_interact(call):
        raise call.excinfo.value

    @pytest.hookimpl(tryfirst=True)
    def pytest_internalerror(excinfo):
        raise excinfo.value

Then in your "request": "test" launch.json you can toggle that env var:

    {
        "name": "Debug Tests",
        "type": "python",
        "request": "test",
        "console": "integratedTerminal",
        "justMyCode": true,
        "env": {
            "_PYTEST_RAISE": "1"
        },
    }

If _PYTEST_RAISE is set and you check only the Uncaught Exceptions box you will break right where the uncaught exception was raised not before.

I also opened an issue with debugpy and they had some ideas, but no solution today. The _PYTEST_RAISE trick works 100% solves this for me.