tdd.rb

def add_two(number)
    if number.respond_to? :+

        if number.respond_to? :push
            number.push 2
        elsif number.class == String
            number + "2"
        else
            number + 2
        end
    else
        puts "NOT A VALID ANSWER"
    end
end
 
def test_add_two
    puts add_two(1)
    puts add_two(1.0)
    puts add_two(nil)
    puts add_two({})
    puts add_two([])
    puts add_two(false)
    puts add_two("1")
end

test_add_two