unit test cases in Angular 8

we are writing unit test cases for angular 8 application. we have designed some common code with configureTestingModule. When we are trying to run multiple spec files we are getting inject error. what do we need to do to solve this issue.

also we are tying to generate the code coverage from npm test --code-coverage command, we are able to generate the folder but index.html is showing nothing. what setting do I need to place to run code coverage.

Thanks in advance