Angular 6 Unit Tests: An error was thrown in afterAll\nReferenceError: Can't find variable: $ thrown

Question

When running my unit tests, from time to time, even if they pass, at the end of all the tests running, I will get the following error.

On my Jenkins CI build running

Answer 1

In my case

I am using karma-parallel and when I updated the executors number it worked (don't know why)

 parallelOptions: {
      executors: 4, // Earlier it was 5 I have updated it to 4 and it worked
      shardStrategy: 'round-robin',
      ......
 }