[ci] Fixed missing coverage data in parallel tests #677

Running Django tests using the --parallel flag spawns multiple worker subprocesses. By default, coverage.py running in the main process does not trace the code executed inside these worker processes, which leads to an incomplete coverage report.

Setting the COVERAGE_PROCESS_START environment variable in the CI workflow natively instructs coverage.py to initialize itself and gather coverage data within all the newly spawned multiprocessing child processes according to the configurations defined in pyproject.toml.

Fixes #677

Author: shivsubh

.github/workflows/ci.yml

@@ -94,6 +94,7 @@ jobs:
         env:
           SELENIUM_HEADLESS: 1
           GECKO_LOG: 1
+          COVERAGE_PROCESS_START: pyproject.toml
 
       - name: Show gecko web driver log on failures
         if: ${{ failure() }}