me too. I submitted my case on August and got file number around 20 August. On Sep. 5, I received a letter from CIC which asked me to take the test. They said the documents I provided are not enough(I calimed highest point in every sections). They asked me to take the test and send the result to CIC within 120 days, otherwise, they will assign me a lower point.
So, it seems that you don't have to take the test, if you are confident that you can pass the mark with lower point in language ability, say, 10 points.