add code coverage checks

.github/workflows/backend-tests.yaml

@@ -0,0 +1,47 @@
+name: Backend API tests and code coverage
+
+on:
+  - push
+
+jobs:
+  test:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        python-version:
+          - "3.10"
+
+    services:
+      postgres:
+        image: postgres:12  # For best results, match version in use by cloud.gov RDS
+        env:
+          POSTGRES_PASSWORD: postgres
+        options: >-
+          --health-cmd pg_isready
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+          cache: pip
+
+      - name: Install pip
+        run: python -m pip install --upgrade pip
+
+      - name: Install prerequisites
+        run: pip install -r requirements.txt -r requirements.dev.txt
+
+      - name: Run unit tests with test coverage checking
+        run: coverage run -m pytest
+
+      - name: Verify >= 90% test coverage
+        run: coverage report --fail-under=90

.gitignore

@@ -5,3 +5,4 @@ __pycache__
 .pytest_cache
 _site/
 node_modules
+.coverage

README.md

@@ -69,10 +69,16 @@ npm run dev
 
 ## Testing
 
-To run tests, first ensure that the `DB_URI` environment variable is set to an empty test database (example: `postgres://postgres:postgres@localhost:5432/smartpay-test`), then run:
+To run tests with code coverage checking:
 
 ```
-pytest
+coverage run -m pytest
+```
+
+To view the coverage report afterwards:
+
+```
+coverage report
 ```
 
 ## Deployment

requirements.dev.txt

@@ -1,3 +1,4 @@
 flake8==6.0.0
 pytest==7.2.1
-httpx==0.23.3
+httpx==0.23.3
+coverage==7.2.3