Now Teacher can see only current unit and grade Unit Tests and Practise Tests
in test_exam_unset: make sure we're in the correct grade and unit
Merge branch 'nalanda-rct3' into student_testing_grade_unit_mapping
Merge pull request #2681 from anuragkanungo/student_testing_grade_unit_mapping

Now Teacher can see only current unit and grade Unit Tests and Practise Tests