Amazon Software Development Engineer Software Development Engineer Test interview questions

Since this was a testing interview and not full out development he had some testing terms I had never heard of these include: Equivalence Class Testing Pair Wise Combinatorial Testing Failure Mode Analysis the only one I heard of was: White Box vs Black Box testing The coding portion was not difficult the question was this Write a function that takes two lists of strings and return a list of Strings with all of the intersections of the strings ex: List1 = {"a","a","a", "b", "d"} List2 = {"a", "a", "c", "d"} expectedReturn={"a","a","d"} Also he asked what tests cases I would use to validate the function also he wanted to know the run time analysis of the function