CourseEnrollment adding signal results into failing test

Hi, I’ve a new field that I want to set whenever a user is enrolled in some specific course. The simplest approach was to add a post_save signal on CourseEnrollment. However, doing this results in multiple failed unit test cases (65 to be precise from lms, cms, common). Am I missing something in adding a signal on CourseEnrollment?

P.S. Test cases fails on accessing course through instance.course of CourseEnrollment.