Tests always exit with status code 0

Regardless of whether tests pass the task will exit with a status code 0.

Verified by cloning and adding the following test

``` js
expect(false).to.be.ok;
```

Reproduce the issue by adding the shown failing assertion and running the repository's test task, then trace the test entry point that determines the process status. Done means a failing test causes a nonzero exit status while passing tests still exit successfully.

Written by the indexing model from the issue text.