Tests and Quizzes play an important role in e-learning and provide an array of benefits for both the learner and the instructor.
Testing and quizzing online will usually provide the user with results instantly. This is good for students because it allows them to know what they did wrong immediately, what they need to focus on, and how to improve should they have to retake the test.
Tests and quizzes have always been a motivator to study harder when students know that their progress will be judged upon an exam, a performance review etc. It sets a deadline for when material needs to be learned by and diligent students know they must adhere to that.