prop_minimum' :: [Integer] -> Property
prop_minimum' integerList

 =      integerList /= []
    ==> minimum' integerList == Data.List.minimum integerList
prop_minimum' :: [Integer] -> Property
prop_minimum' integerList

 =      integerList /= []
    ==> minimum' integerList == Data.List.minimum integerList
prop_minimum' integerList

 =      integerList /= []
    ==> minimum' integerList == Data.List.minimum integerList