Forgive me but I am really confused with your sentences and ideas.
The debate about how to assess ability of students at university is one of the most difficult problems needed to deal with
in here which one are you referring to as difficult, is it the debate or assessing the ability of students?
First, using only formal examination is not enough to test knowledge of students.Teachers do not enable to know whether the students do the work himself. Ideas that students used to write in their exams may be collected from internet easily .
on the highlighted words, are you referring to an exam or homework?
Second, continuous assessment should be used throughout a course to know fully ability of students.
the key word "continuous" means daily.So
the purpose of continuous assessment is to measure the progress of one's learning.
Sorry, but I think you need to try harder on your works...