I have a service class in an Angular application that I need to write tests for. The service class works well, but I am unable to write the Jasmine unit test.

I have a service that serves a very specific case, gets data from websocket and has to be called recursively to get all results. I’ve managed the service and it looks pretty decent works pretty fast but after trying loads of different ways and even rejigging bits of service, I’ve been unable to write a test for the service.
The service is like so

While running unit tests in my angular application, i am getting this error in all spec files

I have a component with a required model. How do I unit test that the value has been updated?

I am learning Angular unit test for chained promise . Here is code snippet and failed at expectation with error message Expected ” to equal ‘bar’. What is needed to make it success ? I have used Angular 17 and Jasmine.I have tried with fakeAsync with tick & flush .