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Accelerate parallelized tests

You can integrate YourBase Test Acceleration smoothly with your existing parallelization setup in your CI. You can use YourBase Test Acceleration to:

  1. Split your tests across shards, and
  2. Accelerate tests that run on each shard


You’re already successfully running parallel tests across multiple shards.


You’ll need to remove any test splitting solution that you may already have in-place.

This is required because YourBase Test Acceleration is effective only when the test-splitting solution is sticky, i.e. tests don’t get reshuffled across shards when other tests are added or removed. Since most test-splitting solutions aren’t sticky, YourBase Test Acceleration provides its own built-in sticky test-splitting solution.

Steps to accelerate parallelized tests:

  1. Remove your existing test splitting tools, if any. It should appear as if each shard will run the entire test suite.
  2. Set YOURBASE_COHORT_COUNT to your number of cohorts / shards
  3. Set YOURBASE_ACTIVE_COHORT to the ID of the current cohort / shard – starting from 1.

     # For example, if you have 5 shards and are running the 4th shard, you’ll set:
  4. Run your tests as usual.

YourBase Test Acceleration will now just-in-time select and run only the tests that are in the current cohort. This selection will be consistent between runs, i.e. given the same cohort ID and total cohorts, a test will always be selected to be run on the same shard for life.

Pro tip:

As an added benefit of YourBase’s sticky splitting of tests, you can schedule a build for each of the sharded pools of tests—to run sharded builds. This works smoothly because YourBase Test Acceleration will merge graphs from multiple shards, for the same commit, which can be used in future builds.