Assessing understanding of mathematics can also be done by asking students to write test items. Here’s my favorite assessment item. I gave this to a group of teachers. 
Possible answers/ questions.
Year level: Third year (Year 9)
Question 1 – What is the distance of P from the origin?
Question 2 – What is the area of circle P with radius equal to its distance from the origin?
Question 3 – With P as one of the vertex, draw square with area 2 square units.
Year level: Second year (Year 8 )
Question 1 – Write the equation of the line that passes through P and the origin.
Question 2 – Write 3 equations of lines passing through (2,1).
Question 3 – Write the equation of the family of lines passing through (2,1).
Year level: First year (Year 7)
Question 1 – What is the ordinate of point P?
Question 2 – Locate (-2, 1). How far is it from P?
Question 3 – Draw a square PQRS with area 9 square units. What are the coordinates of that square?
How about using this exercise to assess your students? Ask them to construct test items instead of asking them to answer questions.
Here are a few more assessment items which I constructed based on the TIMSS Framework: