Plenty of educational sites come with quizzes and exams to test what their students have learned. Plugins such as Quizmaker let you create custom exams for your students. It supports unlimited tests and questions. It displays questions in random order.
The plugin allows users and groups to be assigned to tests. It provides reports and explanations. When done, results can be exported to CSV. The certificate composer allows you to prepare and offer test takers a certificate after they have passed a test.
The plugin offers WooCommerce integration. awstheme is the developer behind it.