test: fix forecast csv mock target

[timothykou]

Pull Request

Description

Addresses #231.

This is a small test-only follow-up to the slow CI/unit-test investigation. tests/unit/test_generate_forecast.py already tried to mock run_forecast, but it patched quartz_solar_forecast.forecast.run_forecast. The code under test imports run_forecast directly into quartz_solar_forecast.utils.forecast_csv, so the mock did not intercept the call and the unit test still exercised the real forecast path.

This changes the test to patch quartz_solar_forecast.utils.forecast_csv.run_forecast, which is the symbol actually used by write_out_forecasts.

Performance / CI relevance:

• Before this change, local instrumentation showed test_generate_forecast made 5 live Open-Meteo calls.
• After this change, the same test passes with Open-Meteo calls: 0.
• The targeted test body is reported by pytest as 0.01s with --durations=0.

This intentionally does not try to solve all of #231 in one PR. Other unit tests still make live Open-Meteo calls, so this is a narrow first step rather than a full closure.

How Has This Been Tested?

uv sync
.venv/bin/python -m ruff check tests/unit/test_generate_forecast.py
.venv/bin/python -m pytest tests/unit/test_generate_forecast.py::test_generate_forecast -q --durations=0

Results:

• Ruff: All checks passed!
• Targeted pytest: 1 passed; slowest call 0.01s
• Guard check with openmeteo_requests.Client.weather_api patched to fail: 1 passed, Open-Meteo calls: 0

I also ran the full unit suite with a local requests-cache==1.3.2 override because current main is affected by the separate requests-cache==1.2.0 issue:

uv pip install requests-cache==1.3.2
.venv/bin/python -m pytest tests/unit -q --durations=15

Result: 22 passed, 4 warnings in 171.77s. The suite is still slow because other unit tests continue to call live weather APIs; those should be addressed separately.

• Yes

Checklist:

• My code follows OCF's coding style guidelines
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation - not needed for this test-only fix
• I have added tests that prove my fix is effective or that my feature works
• I have checked my code and corrected any misspellings

[timothykou]

CI note: the visible red branch_ci / test-unit (3.11) check was cancelled, and before cancellation the log shows the pull_request_target workflow checked out refs/remotes/origin/main, not this PR branch. The regular fork pull_request workflow is action_required, likely waiting for maintainer approval. This PR's targeted local verification is in the PR body; the failing/cancelled unit check is not a clean result for this branch.