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Running tests in parallel

Though we support modeling a pipeline into a DAG structure to shorten the overall build time but sometimes it's not enough like executing a large test suite can slowdown the entire pipeline. You could use parallelism to split your test suite across a few jobs and save time.

To create multiple instances of a task, you can use parallelism property and split your test suite. In order to run it as fast it possible, we need to ensure the steps will run a subset of test suite in a way that all commands complete at the same time to avoid a slow pipeline bottleneck. Razorops also injects two special environment variables to help you dynamically split the test suite -

  • CI_NODE_INDEX the CI node index (between 0 to n if parallelism: n)

  • CI_NODE_TOTAL the total number of CI nodes (n if parallelism: n)

To split the test suite, you can use various tools and libraries as per your language framework like parallel_tests for ruby.

    parallelism: 6
    - checkout
    - run: yarn test

    depends: [e2e-tests]

The above template will create 6 independent tasks with the same set of steps running parallely. Any task depending on the parallel task will run when all instances of parallel tasks are completed.

| e2e-tests |  ->  |e2e-tests-0|
                   |   ......  |    ---->  | deploy|

 └---✔ ci                                                  
     ├-✔ e2e-tests                                         
     | └-·-✔ e2e-tests-0   32s       
     |   ├-✔ e2e-tests-1   30s       
     |   ├-✔ e2e-tests-2   23s       
     |   ├-✔ e2e-tests-3   32s       
     |   ├-✔ e2e-tests-4   30s       
     |   └-✔ e2e-tests-5   23s       
     └-✔ deploy            19s