operation AddQuestion is
   inputs: Question*, Test;
   outputs: Test;
   description: (*
	AddQuestion adds the given Question* to the given Test, which in 
	turn produces an updated Test containing that Question.
   *);
end AddQuestion;


operation RemoveQuestion is
   inputs: ID*, Test;
   outputs: Test;
   description: (*
	RemoveQuestion removes the Question* with the matching given ID* 
	from the given Test, which in turn produces an updated Test 
	without a Question* matching the given ID*.
   *);
end RemoveQuestion;


operation EditQuestion is
   inputs: ID, Question, Test;
   outputs: Test;
   description: (*
	EditQuestion finds the Question on the given Test with an ID
	matching the given ID.  This Question is replaced with the
	given updated or edited Question and put back in the Test,
	which is then returned.
   *);
end EditQuestion;


operation ReplaceQuestion is
   inputs: ID, Question, Test;
   outputs: Test;
   description: (*
	ReplaceQuestion replaces the Question with matching the 
	given ID(which is contained in the given Test) with the 
	given Question and puts it into the given Test. The 
	result is a new Test with one removed Question and a 
	new Question replacing it.
   *);
end ReplaceQuestion;