It looks like your core issue is the ERROR: file not found: pandas message in the test discovery log—this means pytest can't locate the test suite properly in your container setup, even though it works outside. Let's walk through the fixes step by step:

1. Ensure Full Development Dependencies Are Installed #

Container environments often start with minimal setups, so you might be missing the required dev packages for pandas testing. Run this command in your container's terminal to install pandas in editable mode with all dev dependencies:

pip install -e .[dev]

This ensures pytest has access to all the libraries and test utilities it needs to discover and run pandas tests.

2. Verify VS Code's Test Configuration #

Your VS Code pytest args might be misconfigured. Check or create the .vscode/settings.json file in your workspace with these settings:

{
    "python.testing.pytestArgs": [
        "pandas",
        "--rootdir",
        "/workspaces/pandas-dev"
    ],
    "python.testing.unittestEnabled": false,
    "python.testing.pytestEnabled": true
}

This explicitly tells pytest to look for tests in the pandas directory and sets the correct root directory for the repository. After updating the settings, restart VS Code's test discovery (you can use the "Restart Test Discovery" option in the Testing sidebar).

3. Test Manually in the Terminal to Isolate the Issue #

To rule out VS Code-specific problems, run pytest directly in your container's terminal:

cd /workspaces/pandas-dev
pytest pandas/tests/

If this command discovers and runs tests successfully, the problem is definitely in VS Code's test configuration. If it still fails, double-check that you've installed all dependencies correctly (step 1) and that the repository was cloned fully in the container.

4. (Optional) Fix the Matplotlib Deprecation Warning #

While this warning isn't causing the test discovery failure, it's easy to fix to clean up your logs. Open pandas/util/_test_decorators.py and modify line 97 to use explicit keyword parameters:

# Replace this
mod.use("Agg", warn=True)
# With this
mod.use(backend="Agg", warn=True)

This aligns with Matplotlib's newer API requirements and eliminates the deprecation message.

After completing these steps, your test discovery should work in the container environment just like it does outside.

内容的提问来源于stack exchange，提问作者ignoring_gravity