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Merged
Mossaka merged 3 commits into from
Jan 17, 2026
Merged

feat(ci): implement test parallelization to reduce CI time #255

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Initial plan
Copilot Jan 17, 2026
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feat(ci): implement test parallelization to reduce CI time
Copilot Jan 17, 2026
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Merge remote-tracking branch 'origin/main' into copilot/implement-tes…
Mossaka Jan 17, 2026
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34 changes: 34 additions & 0 deletions TESTING.md
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Expand Up @@ -197,6 +197,40 @@ CI checks include:
4. Coverage report generation
5. Coverage threshold validation

### Test Parallelization Strategy

The project uses a multi-level parallelization strategy to optimize CI time:

#### Unit Tests (Jest Workers)
- Unit tests run in parallel using Jest's worker pool
- Configuration: `maxWorkers: '50%'` uses half of available CPU cores
- Tests are isolated and have no shared state, making them safe to parallelize
- Run time: ~6-8 seconds for 549 tests

#### Integration Tests (GitHub Actions Matrix)
- Integration tests run in separate GitHub Actions runners using a matrix strategy
- Each test file runs in its own isolated environment to avoid Docker conflicts
- Test files run in parallel across multiple runners:
- `basic-firewall.test.ts` - Core firewall functionality
- `robustness.test.ts` - Comprehensive edge cases
- `volume-mounts.test.ts` - Volume mount functionality
- `container-workdir.test.ts` - Working directory configuration
- `no-docker.test.ts` - Docker-in-Docker removal verification

**Why Integration Tests Can't Use Jest Workers:**
- Integration tests use Docker containers that share network resources
- Running multiple tests simultaneously would cause:
- Docker network subnet pool exhaustion
- Container name conflicts
- Port binding conflicts
- The `maxWorkers: 1` setting in `jest.integration.config.js` ensures sequential execution within each runner

**Benefits of Matrix Strategy:**
- Each test file runs on a dedicated runner (full isolation)
- All test files run in parallel (reduces wall-clock time)
- `fail-fast: false` ensures all tests complete even if one fails
- Individual test artifacts are captured for failed tests

## Debugging Tests

### Running Tests in Debug Mode
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3 changes: 3 additions & 0 deletions jest.config.js
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Expand Up @@ -22,4 +22,7 @@ module.exports = {
statements: 38,
},
},
// Parallel test execution - use 50% of available CPUs to balance speed and resource usage
// Unit tests are isolated and safe to run in parallel
maxWorkers: '50%',
};
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