I’m trying to use the pytest_sessionstart method in my Pytest environment on Windows 10 with Python 3.9. My goal is to perform some initialization before any test runs. I set up a conftest.py file expecting it to trigger the session start, but nothing seems to happen. I’m not seeing any errors, but also none of my setup code executes. I want to understand why pytest_sessionstart isn’t firing and how I can resolve this.
Ran into this issue with pytest_sessionstart myself many times, and it can be quite puzzling.
The problem often arises from the method not being correctly detected due to its placement or a simple misspelling in your conftest.py. Ensure that pytest_sessionstart is defined within the top-level of your conftest.py without any indentation. Pytest hooks like pytest_sessionstart need to be top-level functions to be picked up correctly during the test run initialization.
Here is the snippet that worked for me: python def pytest_sessionstart(session): print(“Session is starting”) # Add your initialization code here
Make sure this is placed directly within your conftest.py file. Check if your IDE might have added any spaces or indents by accident. Small syntax issues like this are common when the hooks don’t fire as expected.
Also, verify you’re not overriding or having multiple conftest.py files along your test directory structure that might be interfering. Consistently use this structure to have a reliable test execution session.
When dealing with pytest hooks, always remember their scope and import rules to avoid surprises in larger test suites.
Initially, I followed the typical way to use pytest_sessionstart but faced a strange issue where it didn’t execute. After some digging, I realized my pytest.ini configuration was missing, which affected how my session was being initialized.
Pytest can be a bit tricky with configuration. If you have a pytest.ini, ensure that it is in the root directory where your tests are running. The lack of proper config can prevent hooks from executing as they should. The pytest_sessionstart method is also session-scoped, needing to run once before any tests, which sometimes clashes with other pytest plugins you might have installed.
Here’s how you might set it up:
[pytest] addopts = -v
This simple addition can sometimes resolve configuration recognition problems by ensuring pytest operates in verbose mode, providing more info on what’s running. Update your pytest.ini to ensure it’s detected properly.
Interestingly, plugin and dependency configurations can also interfere. Consider disabling plugins to troubleshoot, then selectively re-enable them to identify any conflicts.