Azure DevOps - Pytest unit tests started failing

Question

I have a python application that has pytest unit tests running as part of a build on Azure DevOps. The tests have started failing this morning without any changes to the code.

Here's a minimal reproducible example. I have a file called test_a.py with the following contents:

def test_assert_true():
    assert True

Here's my build pipeline:

trigger:
- '*'

pool:
  vmImage: windows-latest
  name: 'Azure Pipelines'

stages:
- stage: Build
  jobs:
  - job: RunPythonUnitTests
    displayName: Test - Python Unit Tests
    steps:
    - task: UsePythonVersion@0
      inputs:
        versionSpec: '3.7'
        architecture: 'x64'
    - script: |
        pip install pytest pytest-azurepipelines pyspark
        pytest  
      displayName: 'Run tests' 

The Run Tests step is failing. The logs are showing the following errors:

============================= test session starts =============================
platform win32 -- Python 3.7.9, pytest-7.1.0, pluggy-1.0.0
rootdir: D:\a\1\s
plugins: azurepipelines-0.8.0
collected 1 item
INTERNALERROR> Traceback (most recent call last):
INTERNALERROR>   File "c:\hostedtoolcache\windows\python\3.7.9\x64\lib\site-packages\_pytest\main.py", line 268, in wrap_session
INTERNALERROR>     session.exitstatus = doit(config, session) or 0
INTERNALERROR>   File "c:\hostedtoolcache\windows\python\3.7.9\x64\lib\site-packages\_pytest\main.py", line 321, in _main
INTERNALERROR>     config.hook.pytest_collection(session=session)
INTERNALERROR>   File "c:\hostedtoolcache\windows\python\3.7.9\x64\lib\site-packages\pluggy\_hooks.py", line 265, in __call__
INTERNALERROR>     return self._hookexec(self.name, self.get_hookimpls(), kwargs, firstresult)
INTERNALERROR>   File "c:\hostedtoolcache\windows\python\3.7.9\x64\lib\site-packages\pluggy\_manager.py", line 80, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
INTERNALERROR>   File "c:\hostedtoolcache\windows\python\3.7.9\x64\lib\site-packages\pluggy\_callers.py", line 60, in _multicall
INTERNALERROR>     return outcome.get_result()
INTERNALERROR>   File "c:\hostedtoolcache\windows\python\3.7.9\x64\lib\site-packages\pluggy\_result.py", line 60, in get_result
INTERNALERROR>     raise ex[1].with_traceback(ex[2])
INTERNALERROR>   File "c:\hostedtoolcache\windows\python\3.7.9\x64\lib\site-packages\pluggy\_callers.py", line 39, in _multicall
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "c:\hostedtoolcache\windows\python\3.7.9\x64\lib\site-packages\_pytest\main.py", line 332, in pytest_collection
INTERNALERROR>     session.perform_collect()
INTERNALERROR>   File "c:\hostedtoolcache\windows\python\3.7.9\x64\lib\site-packages\_pytest\main.py", line 659, in perform_collect
INTERNALERROR>     self.config.pluginmanager.check_pending()
INTERNALERROR>   File "c:\hostedtoolcache\windows\python\3.7.9\x64\lib\site-packages\pluggy\_manager.py", line 265, in check_pending
INTERNALERROR>     % (name, hookimpl.plugin),
INTERNALERROR> pluggy._manager.PluginValidationError: unknown hook 'pytest_warning_captured' in plugin <module 'pytest_azurepipelines' from 'c:\\hostedtoolcache\\windows\\python\\3.7.9\\x64\\lib\\site-packages\\pytest_azurepipelines.py'>
Result Attachments will be stored in LogStore

Anyone know how to get around this?

Answer 1

Looks like this was caused by a breaking change in the latest version of pytest.

https://pypi.org/project/pytest/#history

Fixed it by specifying the previous version in the pipeline:

- script: |
    pip install pytest==7.0.1 pytest-azurepipelines pyspark 
    pytest