Add comprehensive test suite with GitHub Actions CI/CD

- Refactor code into testable bot.py module with MastodonRSSBot class
- Create 20+ unit tests covering core functionality and edge cases
- Create 10+ integration tests for RSS parsing and Mastodon posting
- Add GitHub Actions workflow for automated testing
  - Unit tests on Python 3.10, 3.11, 3.12
  - Integration tests with mocked external services
  - Code quality checks (flake8, black, mypy)
  - Docker build validation
- Configure pytest with 80% minimum coverage requirement
- Add test dependencies in requirements-test.txt
- Update .gitignore to exclude test artifacts
- Add comprehensive TESTING.md documentation
- Add test status badge to README
- Maintain full backward compatibility with existing setup

.github/workflows/test.yml

@@ -0,0 +1,162 @@
+name: Tests
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  unit-tests:
+    name: Unit Tests
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ['3.10', '3.11', '3.12']
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+        cache: 'pip'
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -r requirements-test.txt
+
+    - name: Run unit tests
+      run: |
+        pytest test_bot.py -m "not integration" --cov=bot --cov=main --cov-report=xml --cov-report=term
+
+    - name: Upload coverage to Codecov
+      uses: codecov/codecov-action@v4
+      with:
+        file: ./coverage.xml
+        flags: unittests
+        name: codecov-${{ matrix.python-version }}
+        fail_ci_if_error: false
+
+  integration-tests:
+    name: Integration Tests
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ['3.10', '3.11', '3.12']
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+        cache: 'pip'
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -r requirements-test.txt
+
+    - name: Run integration tests
+      run: |
+        pytest test_integration.py --cov=bot --cov-report=xml --cov-report=term
+
+    - name: Upload coverage to Codecov
+      uses: codecov/codecov-action@v4
+      with:
+        file: ./coverage.xml
+        flags: integration
+        name: codecov-integration-${{ matrix.python-version }}
+        fail_ci_if_error: false
+
+  code-quality:
+    name: Code Quality
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Set up Python
+      uses: actions/setup-python@v5
+      with:
+        python-version: '3.11'
+        cache: 'pip'
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -r requirements-test.txt
+
+    - name: Run flake8
+      run: |
+        flake8 bot.py main.py --count --select=E9,F63,F7,F82 --show-source --statistics
+        flake8 bot.py main.py --count --max-complexity=10 --max-line-length=127 --statistics
+
+    - name: Run black check
+      run: |
+        black --check bot.py main.py test_bot.py test_integration.py
+
+    - name: Run mypy
+      run: |
+        mypy bot.py main.py --ignore-missing-imports
+      continue-on-error: true
+
+  docker-build-test:
+    name: Docker Build Test
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3
+
+    - name: Build Docker image
+      uses: docker/build-push-action@v5
+      with:
+        context: .
+        push: false
+        tags: masto-rss:test
+        cache-from: type=gha
+        cache-to: type=gha,mode=max
+
+    - name: Test Docker image structure
+      run: |
+        docker run --rm masto-rss:test python --version
+        docker run --rm masto-rss:test pip list | grep feedparser
+        docker run --rm masto-rss:test pip list | grep Mastodon
+
+  all-tests-pass:
+    name: All Tests Passed
+    needs: [unit-tests, integration-tests, code-quality, docker-build-test]
+    runs-on: ubuntu-latest
+    if: always()
+
+    steps:
+    - name: Check test results
+      run: |
+        if [ "${{ needs.unit-tests.result }}" != "success" ]; then
+          echo "Unit tests failed"
+          exit 1
+        fi
+        if [ "${{ needs.integration-tests.result }}" != "success" ]; then
+          echo "Integration tests failed"
+          exit 1
+        fi
+        if [ "${{ needs.code-quality.result }}" != "success" ]; then
+          echo "Code quality checks failed"
+          exit 1
+        fi
+        if [ "${{ needs.docker-build-test.result }}" != "success" ]; then
+          echo "Docker build test failed"
+          exit 1
+        fi
+        echo "All tests passed successfully!"