在使用《Agile Development with Ruby on Rails》一书学习RoR时，使用assert_equal和.join方法未能通过单元测试

Question

我刚刚开始学习 Ruby on Rails，甚至是 Ruby 语言本身。 阅读迭代 B2：模型的单元测试并进行以下练习后： 1. 验证选项 :length 检查模型属性的长度。向 Product 模型添加验证，以检查标题是否至少有 10 个字符长。 2. 更改与您的验证之一相关的错误消息。

我将以下代码放入 /models/product.rb

validates_uniqueness_of :title, :message => 'has already been taken'
validates_length_of :title, :minimum => 8, :message => 'must be at least 8 letters'

并将以下代码放入 /unit/product_test.rb

test "product is not valid without a 8 letters title" do
product = Product.new(:title =>"12345678",
                      :description => "yyy",
                      :price => 1,
                      :image_url => "fred.gif")
product.title = "abcdefg"
assert product.invalid?
assert_equal "must be at least 8 letters", product.errors[:title].join('; ')
product.title = "abcdefgh"
assert product.valid?    
end

test "product is not valid without a unique title" do
product = Product.new(:title => products(:lighting).title,
                      :description => "yyy",
                      :price => 1,
                      :image_url => "fred.gif")
assert !product.save
assert_equal "has already been taken", product.errors[:title].join('; ')

end

但当我运行 rake 测试时，出现故障，我不知道如何解决它，它显示：

1) Failure:
test_product_is_not_valid_without_a_unique_title(ProductTest)
/Users/youngoo/Development/RubyonRails/anaheim/test/unit/product_test.rb:66]:
<"has already been taken"> expected but was
<"has already been taken; must be at least 8 letters">.

这是如何发生的？我该怎么办？ 我认为问题与 join 方法有关 谢谢！

Answer 1

尝试像这样使用 assert_match 而不是 assert_equal...

assert_match /has already been taken/, product.errors[:title].join('; ')

您走在正确的道路上。

编辑：如果assert_match要折旧，

assert_not_nil /has already been taken/.match(product.errors[:title].join('; ')

应该产生相同的结果