Browser Use Demo - Test Suite

Comprehensive test suite for the refactored Browser Use Demo with extensive edge case coverage.

Installation

# Install test dependencies
pip install -r test-requirements.txt

# Or install with extras
pip install -e ".[test]"

Running Tests

Run all tests

pytest tests/

Run with coverage report

pytest tests/ --cov=browser_tools_api_demo --cov-report=html
# Open htmlcov/index.html to view coverage report

Run specific test file

pytest tests/test_message_renderer.py -v

Run specific test class or method

pytest tests/test_message_renderer.py::TestMessageRenderer -v
pytest tests/test_message_renderer.py::TestRenderMethod::test_render_string_message -v

Run tests by marker

# Run only integration tests
pytest -m integration

# Run tests excluding integration
pytest -m "not integration"

# Run async tests
pytest -m asyncio

Test Structure

tests/
├── conftest.py                      # Shared fixtures and mocks
├── test_message_renderer.py         # MessageRenderer class tests (~300 test cases)
├── test_streamlit_helpers.py        # Helper function tests (~150 test cases)
└── test_integration.py              # End-to-end integration tests (~50 test cases)

Test Coverage

The test suite covers:

MessageRenderer (test_message_renderer.py)

• Initialization with various state configurations
• Rendering all message types (string, dict, ToolResult)
• Conversation history rendering with complex structures
• Edge cases: empty messages, None values, circular references
• Error handling: malformed data, missing fields, exceptions
• Unicode and special character handling
• Performance with large messages

Streamlit Helpers (test_streamlit_helpers.py)

• setup_state() with fresh and partial initialization
• Environment variable handling (present/missing/invalid)
• Lambda evaluation in state initialization
• get_or_create_event_loop() with various loop states
• authenticate() with different providers and key states
• Concurrent access and thread safety
• Error recovery scenarios

Integration Tests (test_integration.py)

• Complete message rendering pipeline
• State initialization and persistence
• Event loop management with async operations
• Error propagation across components
• Full user interaction workflow
• Performance with large datasets (1000+ messages)
• Deeply nested content structures

Edge Cases Covered

1. Boundary Conditions

   • Empty strings, lists, dictionaries
   • Single item collections
   • Maximum size inputs (100k+ character messages)
   • Null/None values

2. Type Mismatches

   • Wrong types for expected fields
   • Missing required fields
   • Extra unexpected fields
   • Invalid message structures

3. State Inconsistencies

   • Tools referenced but not in session_state
   • Partially initialized state
   • Concurrent modifications
   • Corrupted state

4. Error Conditions

   • Import errors
   • Asyncio exceptions
   • Environment variable errors
   • Lambda evaluation failures
   • Base64 decode errors

5. Performance Edge Cases

   • Very large message histories (1000+ messages)
   • Deeply nested content (100+ levels)
   • Circular references
   • Unicode and special characters

Mocking Strategy

Streamlit Components

All Streamlit components are mocked to enable testing without a running Streamlit server:

• st.session_state
• st.chat_message
• st.markdown, st.write, st.error, st.code, st.image
• st.chat_input, st.stop

External Dependencies

• BrowserTool - Mocked to avoid Playwright dependencies
• asyncio event loops - Mocked for controlled testing
• Environment variables - Mocked via monkeypatch

Fixtures

Key fixtures provided in conftest.py:

• mock_streamlit - Complete Streamlit mocking setup
• mock_browser_tool - BrowserTool mock
• sample_tool_result - Various ToolResult configurations
• sample_messages - Diverse message structures for testing
• edge_case_messages - Messages designed to trigger edge cases
• mock_asyncio_loop - Controlled event loop for testing
• mock_environment - Environment variable setup
• clean_environment - Remove environment variables

Continuous Integration

To run tests in CI:

# Install dependencies
pip install -e ".[test]"

# Run tests with coverage
pytest tests/ --cov=browser_tools_api_demo --cov-report=xml --cov-report=term

# Generate coverage badge
coverage-badge -o coverage.svg

Contributing

When adding new features or refactoring:

1. Add corresponding tests for new functionality
2. Ensure all edge cases are covered
3. Run the full test suite before committing
4. Maintain >95% code coverage
5. Update this README if test structure changes