Test server crashes on client-side changes

[Albinutte]

Describe the bug

Making code changes on the client side while running test server with another driver crashes it.

To Reproduce

• Start test server with METEOR_DISABLE_OPTIMISTIC_CACHING=1 TEST_CLIENT=0 TEST_SERVER=0 meteor test --port 4000 --full-app --driver-package tmeasday:acceptance-test-driver.
• Make any code changes on the client side.

The server is going to crash with this error:

=> Client modified -- refreshing
node:internal/process/promises:394
    triggerUncaughtException(err, true /* fromPromise */);
    ^
{
  stack: "TypeError: Cannot read properties of undefined (reading 'runClient')\n" +
    '    at clientTests (packages/meteortesting:mocha/server.js:153:22)\n' +
    '    at packages/meteortesting:mocha/server.js:244:3\n' +
    '    at packages/inter-process-messaging.js:99:48\n' +
    '    at Set.forEach (<anonymous>)\n' +
    '    at packages/inter-process-messaging.js:99:21\n' +
    '    at processTicksAndRejections (node:internal/process/task_queues:105:5)',
  message: "Cannot read properties of undefined (reading 'runClient')"
}

Expected behavior

Server restarts without a problem.

Desktop (please complete the following information):

• OS: MacOS
• Browser: N/A
• Version: Meteor v3.1.2, meteortesting:mocha@3.2.0

Additional context

The error appeared after migrating from Meteor 2.16 and meteortesting:mocha@2.1.0.

[github-actions]

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[jankapunkt]

hi @Albinutte I just checked the tmeasday:acceptance-test-driver is last released from 2016 and is likely having issues with newer mocha packages. Is the package using this package as a basis for its tests?