You have been provided with source code (with some test cases) for a “user management” system. It contains Users, Groups and Memberships.

Update failing unit test of the project. Ignore @Ignored UT

This codebase allows nested groups; groups that are members of other groups. However, this has not been implemented fully yet. Go through the codebase and make changes as needed to finish the nested groups support. Please also ensure that there is appropriate test coverage for your newly added feature.