Why can't my new students take tests?

QUESTION

I replaced all my students from last year with my new students.  But whenever they try to test, it says "testing finished".  What's going on?

ANSWER

 If you edit a class and change the names, then you have only changed the name of the student, but all the test scores for the student remain.  It the same as if you simply changed the spelling of a student's name from "Sarah" to "Sara" or from "Zak" to "Zachary".  Editing the names of an existing class does not introduce a new student.  If you have done this, then those "new students" are really your old students, and the grade table will be full of the grades from last year.  Click on "grades" and change the time period to "All Time" and what do you see?

 It is important, if you have a new class, to use the "New Class" option in the menu, not simply to "change the class list".