I was asked two fairly simple problems which I solved but the interviewer wanted to talk about what testcases I would write for them. I am a new college grad and was caught off guard and mumbled something. I was wondering if there is list of good generic test cases to check for for each question type that I should always keep at the back of my head:

Example:

Test cases for trees:
	no nodes
	single root node 
	degenerate tree ( all left and all right nodes only )