ci: Gather and report test coverage in test workflow

.github/workflows/test.yml

@@ -94,7 +94,28 @@ jobs:
       - name: Run tests
         env:
           DATABASE_URL: postgresql://postgres:postgres@localhost/medical_transcription_test
-        run: mix test
+        run: mix test --cover --export-coverage default
+
+      - name: Export code coverage
+        id: coverage_percent
+        run: |
+          COVERAGE_RESULTS=$(mix test.coverage) || true
+          echo $COVERAGE_RESULTS
+
+          COVERAGE_PERCENTAGE=$(echo $COVERAGE_RESULTS | grep "Coverage:" | awk -F ':' '{print $2}' | awk '{$1=$1;print}')
+          echo "value=$COVERAGE_PERCENTAGE" >> $GITHUB_OUTPUT
+
+      - name: Send coverage results to Slack
+        uses: slackapi/slack-github-action@v1.23.0
+        if: ${{ github.ref == 'refs/head/main' }}
+        with:
+          payload: |
+            {
+              "appName": "MediCode",
+              "percent": "${{ steps.coverage_percent.outputs.value }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
 
       # - name: Upload Bumblebee model artifacts
       #   uses: actions/upload-artifact@v4