when you go in the test use your common sense and give it some time. There is no need to rush. They give you 30 minutes to do the test and its a lot of time to answer 20 questions. Be confident and do not panic. Its multiple choice so its very easy to pick the right answer. After finishing the test, double check your answers and as I said do not rush..
Its very simple questions there, What people have been saying that they change the questions, well they have to because they can't give you copy paste from the book. They want you to use your common sense too
I give you one example what kinda question you can get in the test
1) what is the definition of volunteer ?  you have to pick one answer right from 4 options
Now this question some one can even answer without reading the book
I do not know if this question is in "discover Canada book" or not
2) What is the job of police in Canada
You have to pick one right from 4 options. Obviously some one can easily guess from 4 options what the job of police can be
3) what are responsibilities of Canadian citizens
I don't think some one can guess it wrong from 4 different options
4) First prime minister of Canada John A Macdonald did what for this country
you have to pick from 4 answers
obviously he worked for democracy...you may not find this question in the book its just a common sense
5) Saskatchewan was once called bed and breakfast of world for what reason
because it produces highest amount of grains and oil seeds
and not because of oil or gas or electricity
So all in all expect these kinda questions.
Go through the book and there is no need to remember all those difficult dates and events etc etc
You should just have a basic idea how this country works and on what principles and how every day life is in here.
Myself I will always welcome questions that are little bit testing and challenging and not copy paste from the book
hope this helps
I am sure after passing this test you will say like every one else oh it was way too easy 

 Good luck!