fails:Range#first returns the specified number of elements from the beginning
fails:Range#first returns an empty array for an empty Range
fails:Range#first returns an empty array when passed zero
fails:Range#first returns all elements in the range when count exceeds the number of elements
fails:Range#first calls #to_int to convert the argument
fails:Range#first raises a TypeError if #to_int does not return an Integer
fails:Range#first truncates the value when passed a Float
fails:Range#first raises a TypeError when passed nil
fails:Range#first raises a TypeError when passed a String
