fails:Time#- decrements the time by the specified amount
fails:Time#- understands negative subtractions
fails:Time#- accepts arguments that can be coerced into Rational
fails:Time#- raises a TypeError if given argument is a coercible String
fails:Time#- raises TypeError on argument that can't be coerced
fails:Time#- raises TypeError on nil argument
fails:Time#- tracks microseconds
fails:Time#- tracks nanoseconds
fails:Time#- maintains precision
fails:Time#- maintains microseconds precision
fails:Time#- maintains nanoseconds precision
fails:Time#- maintains subseconds precision
fails:Time#- returns a UTC time if self is UTC
fails:Time#- returns a non-UTC time if self is non-UTC
fails:Time#- returns a time with the same fixed offset as self
fails:Time#- does not return a subclass instance
