unhandled rejection is bubbling out from unit test

[eoln]

I picked a random test case to make this POC: #753

It shows that unhandled promise rejection is bubbled out from the unit test
I also fixed the test so now it fails.
If you comment out the newly added L197 and run the test in console output you will see the message from process.on handler which will be called if the unit test code is not handling the error properly.

There are other 47 tests from which unhandled rejections are bubbling out