Question

我的age模型上有一个Waiver方法，如下所示：

  def age(date = nil)

    if date.nil?
      date = Date.today
    end
    age = 0
    unless date_of_birth.nil?
      age = date.year - date_of_birth.year
      age -= 1 if date < date_of_birth + age.years #for days before birthday
    end
    return age
  end

然后我有一个看起来像这样的规范：

it "calculates the proper age" do
 waiver = FactoryGirl.create(:waiver, date_of_birth: 12.years.ago)
 waiver.age.should == 12
end

当我运行此规范时，我得到comparison of Date with ActiveSupport::TimeWithZone failed。我做错了什么？

Failures:

  1) Waiver calculates the proper age
     Failure/Error: waiver.age.should == 12
     ArgumentError:
       comparison of Date with ActiveSupport::TimeWithZone failed
     # ./app/models/waiver.rb:132:in `<'
     # ./app/models/waiver.rb:132:in `age'
     # ./spec/models/waiver_spec.rb:23:in `block (2 levels) in <top (required)>'

Answer 1

您正在将Date的实例与表达式ActiveSupport::TimeWithZone中的date < date_of_birth + age.years实例进行比较; ActiveSupport :: TimeWithZone是according to the docs，类似于时间的类，可以表示任何时区的时间。您无法在不执行某种转换的情况下比较Date和Time个对象。在控制台上尝试Date.today < Time.now;你会看到类似的错误。

12.years.ago等表达式和典型的ActiveRecord时间戳是ActiveSupport :: TimeWithZone的实例。您最好确保只处理Time个对象或Date个对象，但不能同时处理这两个对象。为了使您的比较与日期相比，表达式可以写成：

age -= 1 if date < (date_of_birth + age.years).to_date

Date与ActiveSupport :: TimeWithZone的比较失败

1 个答案: