AWS Certified DevOps Engineer – ProfessionalSDLC AutomationHard
A DevOps team is adopting a trunk-based development model with frequent, small commits to the main branch. Their current CI/CD pipeline runs a comprehensive suite of unit, integration, and end-to-end tests sequentially, taking over 45 minutes to complete. This long feedback loop is hindering developer productivity. How can they reduce the total execution time of their test suite without sacrificing test coverage?
- AImplement parallel test execution across multiple CodeBuild instances.
- BRefactor the application to reduce the number of tests required.
- CRun only unit tests in the CI pipeline and defer integration/E2E tests to a nightly build.
- DIncrease the compute resources allocated to the CodeBuild project running the tests.
Show answer & explanationAnswer & explanation
Correct answer: A. Implement parallel test execution across multiple CodeBuild instances.
Parallel test execution allows the test suite to be split and run concurrently across multiple CodeBuild instances or containers, significantly reducing the total execution time without compromising test coverage. This is crucial for maintaining fast feedback loops in trunk-based development.
Why the other options are wrong
- B. Refactoring to reduce tests might compromise test coverage, which goes against the requirement of not sacrificing coverage. The goal is to run existing tests faster, not fewer tests.
- C. Deferring critical tests to nightly builds compromises the 'fail fast' principle of CI/CD and increases the risk of integrating issues into the main branch, which is undesirable for trunk-based development.
- D. Increasing compute resources (e.g., larger CodeBuild instance) might speed up individual test runs but offers diminishing returns and doesn't scale linearly with the number of tests. Parallelization is more effective for large suites.
Parallel Test Execution
A strategy for reducing the overall execution time of a test suite by running multiple tests or test groups concurrently across different environments or processes.
- Significantly reduces CI/CD feedback loop times.
- Can be implemented using multiple CodeBuild instances or test splitting within a single instance.
- Requires careful test suite design to ensure independence between parallelized tests.
Memory trick: Tests running slow? Don't run less, run them all in parallel fast!