Parallel Execution with Pabot
Parallel execution helps reduce test execution time. In Robot Framework, parallelism is achieved using Pabot.
Pabot is an external tool designed specifically for Robot Framework.
What is Pabot?
Pabot:
- Enables parallel execution of Robot Framework tests
- Executes test suites or test cases concurrently
- Is commonly used in CI/CD pipelines
Without Pabot, Robot Framework runs tests sequentially.
Installing Pabot
pip install robotframework-pabot
Verify installation:
pabot --version
Basic Parallel Execution
Run tests in parallel:
pabot tests/
Run with multiple processes:
pabot --processes 4 tests/
Parallel Execution Levels
Pabot supports parallel execution at:
- Suite level
- Test case level (advanced)
Most projects prefer suite-level parallelism for stability.
Thread Safety Considerations
Parallel execution requires:
- Independent test data
- No shared state
- No static/global dependencies
- Isolated browsers and sessions
Failure to ensure thread safety causes flaky tests.
When to Use Pabot
Use Pabot when:
- Test suite execution is slow
- Tests are independent
- CI pipeline time must be reduced
Avoid Pabot when:
- Tests share state
- Environment cannot support parallel load
Common Pabot Issues ❌
- Port conflicts
- Shared test data collisions
- Environment limitations
- Browser driver contention
Best Practices ✅
- Start with low process count
- Parallelize suites, not tests
- Separate smoke and regression
- Monitor system resources
Key Takeaways
- Pabot enables parallel execution
- Improves execution speed
- Requires careful test design
- Essential for large test suites