Add integration test coverage for PR validation

.github/workflows/test.yml

@@ -134,3 +134,111 @@ jobs:
         id: check-types
         run: |
           mypy .
+
+  integration-test:
+    name: Integration Tests (Mocked)
+    runs-on: ubuntu-latest
+
+    defaults:
+      run:
+        shell: bash
+
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v4
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+
+      - uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v5
+        with:
+          python-version: '3.11'
+          cache: 'pip'
+
+      - name: Install Python dependencies
+        run: |
+          pip install -r requirements.txt
+
+      - name: Set PYTHONPATH environment variable
+        run: echo "PYTHONPATH=${GITHUB_WORKSPACE}" >> $GITHUB_ENV
+
+      - name: Run mocked integration tests
+        run: pytest -v tests/integration/test_action_integration.py
+
+  smoke-e2e-test:
+    name: Smoke E2E Test (Real API)
+    runs-on: ubuntu-latest
+    # Only run on PRs from same repo (not forks)
+    if: github.event.pull_request.head.repo.full_name == github.repository
+
+    defaults:
+      run:
+        shell: bash
+
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v4
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+
+      - uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v5
+        with:
+          python-version: '3.11'
+          cache: 'pip'
+
+      - name: Install Python dependencies
+        run: |
+          pip install -r requirements.txt
+
+      - name: Set PYTHONPATH environment variable
+        run: echo "PYTHONPATH=${GITHUB_WORKSPACE}" >> $GITHUB_ENV
+
+      - name: Run action against real repository
+        env:
+          INPUT_TAG_NAME: 'v0.2.0'
+          INPUT_GITHUB_REPOSITORY: 'AbsaOSS/generate-release-notes'
+          INPUT_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          INPUT_CHAPTERS: |
+            [
+              { title: Breaking Changes 💥, label: breaking-change },
+              { title: New Features 🎉, label: enhancement },
+              { title: New Features 🎉, label: feature },
+              { title: Bugfixes 🛠, label: bug }
+            ]
+          INPUT_WARNINGS: 'true'
+          INPUT_PRINT_EMPTY_CHAPTERS: 'false'
+          INPUT_VERBOSE: 'true'
+          INPUT_HIERARCHY: 'false'
+          INPUT_DUPLICITY_SCOPE: 'both'
+          INPUT_PUBLISHED_AT: 'false'
+          INPUT_SKIP_RELEASE_NOTES_LABELS: 'skip-release-notes'
+        run: |
+          # Run the action with verbose/debug logging
+          python main.py > output.txt 2>&1
+          exit_code=$?
+
+          # Display output for debugging
+          echo "=== Action Output ==="
+          cat output.txt
+          echo "=== End of Output ==="
+
+          # Check exit code
+          if [ $exit_code -ne 0 ]; then
+            echo "❌ Action failed with exit code $exit_code"
+            exit 1
+          fi
+
+          # Check for actual generated release notes content (markdown chapters)
+          if grep -q "^### " output.txt; then
+            echo "✅ Action successfully generated release notes with chapters"
+          else
+            echo "❌ No release notes chapters found in output"
+            exit 1
+          fi
+
+          # Verify the action completed successfully
+          if grep -q "completed successfully" output.txt; then
+            echo "✅ Action completed successfully"
+          else
+            echo "⚠️  Warning: Action may not have completed successfully"
+            exit 1
+          fi

DEVELOPER.md

@@ -128,7 +128,56 @@ Unit tests are written using pytest. To run the tests, use the following command
 pytest tests/unit
 ```
 
-This will execute all tests located in the tests directory.
+This will execute all tests located in the tests/unit directory.
+
+## Running Integration Tests
+
+Integration tests verify that different parts of the system work together correctly.
+
+### Mocked Integration Tests
+
+Mocked integration tests run without requiring GitHub API access. They use mocked data to test the action's configuration parsing, input validation, and output formatting.
+
+```shell
+pytest tests/integration/test_action_integration.py -v
+```
+
+These tests:
+- Run on all PRs, including from forks
+- Are deterministic and fast
+- Test action inputs, chapter configuration, and error handling
+- Do not require secrets or network access
+
+### Smoke E2E Tests
+
+Smoke end-to-end tests verify the action works against a real GitHub repository. These tests:
+- Run automatically on same-repo PRs (NOT on forks for security)
+- Use the `GITHUB_TOKEN` secret to access the GitHub API
+- Verify the action can fetch real issues and generate release notes
+- Run with verbose/debug logging enabled to validate output
+
+The smoke E2E test runs automatically in CI as a PR check. It is configured in `.github/workflows/test.yml` and uses the `AbsaOSS/generate-release-notes` repository as a test target. The test validates:
+1. The action exits with code 0 (success)
+2. The output contains "Release Notes" text
+
+To run similar tests locally (requires `GITHUB_TOKEN` environment variable):
+
+```shell
+export INPUT_TAG_NAME="v0.2.0"
+export INPUT_GITHUB_REPOSITORY="AbsaOSS/generate-release-notes"
+export INPUT_GITHUB_TOKEN="your_github_token"
+export INPUT_CHAPTERS='[{"title": "Features", "label": "feature"}]'
+export INPUT_WARNINGS="true"
+export INPUT_PRINT_EMPTY_CHAPTERS="false"
+export INPUT_VERBOSE="true"
+export INPUT_HIERARCHY="false"
+export INPUT_DUPLICITY_SCOPE="both"
+export INPUT_PUBLISHED_AT="false"
+export INPUT_SKIP_RELEASE_NOTES_LABELS="skip-release-notes"
+export PYTHONPATH="${PWD}"
+
+python main.py
+```
 
 ## Code Coverage
 

requirements.txt

@@ -1,6 +1,7 @@
 pytest==9.0.2
 pytest-cov==7.0.0
 pytest-mock==3.15.1
+responses==0.25.3
 pylint==4.0.4
 requests==2.32.5
 black==25.12.0