TA Testing and grading are necessary ingredients of teaching and learning.
Tests give teachers a way of measuring student learning.
Grading gives students feedback on their academic performance. Your exams should test learning objectives and instructional goals that you have emphasized to students throughout the course. You will give a mixed message and students will learn to just memorize, not to analyze. Test topics that were discussed in detail during class. You generally devote class time to discussion of material only if you consider it important to your course goals.