Translating the length validator error message

In the Agile Web Development book, it is suggested to make a unit test as follows:

assert_equal I18n.translate('activerecord.errors.messages.taken'),
             product.errors[:title].join('; ')

I tried using this for other error messages, such as the length validator too_short message, but get errors:

assert_equal I18n.translate('activerecord.errors.messages.too_short', :count=>10),
             product.errors[:title].join('; ')

gives:

<"translation missing: en, activerecord, errors, messages, too_short"> expected but was
<"is too short (minimum is 10 characters)">.

A quick google search suggests others are using activerecord.errors.messages.too_short, but apparently it doesn't work. Is there a different way to access the message开发者_JAVA百科, am I doing something else wrong?

---

ActiveModel handles most of the errors, so the error messages are in errors.messages. The only exception is taken, because the uniqueness validation is ActiveRecord specific.

So you'll need:

assert_equal I18n.translate('errors.messages.too_short', :count=>10),
             product.errors[:title].join('; ')

Here are the messages: https://github.com/rails/rails/blob/master/activemodel/lib/active_model/locale/en.yml