Wie dieses Testdurchlauf zu machen, ich bin ein bisschen verwirrt

Question

das ist mein Geld Klasse

class Money 
    def initialize 
    @amount = 0 
    end 

    def amount 
    @amount 
    end 

    def earn(this_many) 
    @amount += this_many 
    end 

    def spend(this_many) 
    @amount -= this_many 
    end 

end 

mein Versagen Test

def test_cant_spend_money_that_you_dont_have 
    money = Money.new 
    money.earn(75) 
    money.spend(75) 
    assert_equal "You can't spend what you don't have", money.spend(12) 
    assert_equal 0, money.amount 
    end 

Ich bin nicht sicher, wie die Menge Methode zu ändern, um Machen Sie den Test bestanden ... jede Hilfe wird geschätzt.

Answer 1

Sie ändern müssen, sollten Fehler erhöhen, wenn das Konto nicht genug Geld hat, zu verbringen.

class Money 
    class InsufficientFunds < StandardError; end 

    attr_accessor :amount 

    def initialize 
    self.amount = 0 
    end 

    def earn(this_many) 
    self.amount += this_many 
    end 

    def spend(this_many) 
    raise InsufficientFunds, "You can't spend what you don't have" if amount < this_many 
    self.amount -= this_many 
    end 

end 

Und Ihr Testfall sollte

def test_cant_spend_money_that_you_dont_have 
    money = Money.new 
    money.earn(75) 
    money.spend(75) 
    assert_raise Money::InsufficientFunds, "You can't spend what you don't have" do 
    money.spend(12) 
    end 
    assert_equal 0, money.amount 
end 

Answer 2

Ich glaube, Sie

assert_equal "You can't spend what you don't have", money.spend(12) 

zu

money.spend(12) 
assert money.amount > 0, "You can't spend what you don't have"