fails:Fixnum#coerce when given a Fixnum returns an array containing two Fixnums
fails:Fixnum#coerce when given a String raises an ArgumentError when trying to coerce with a non-number String
fails:Fixnum#coerce when given a String returns  an array containing two Floats
fails:Fixnum#coerce raises a TypeError when trying to coerce with nil
fails:Fixnum#coerce tries to convert the given Object into a Float by using #to_f
fails:Fixnum#coerce raises a TypeError when given an Object that does not respond to #to_f
