As mentioned in [#8856](https://github.com/facebook/jest/issues/8856) and [#5494](https://github.com/facebook/jest/pull/5494) the `JEST_WORKER_ID` environment variable is set inside tests. That should also be present when using jest-runner-mocha.
As mentioned in #8856 and #5494 the
JEST_WORKER_IDenvironment variable is set inside tests. That should also be present when using jest-runner-mocha.