Question

I have written a unit test whose assertion fails – I would like to find out why, without having to inspect every attribute of the model.

Here is my test:

test "a correct document should be saved" do
  document = documents(:one)
  document.pdf = File.new("test/files/document_test_file.pdf")
  assert document.save
end

And here is the fixture:

one:
  user_id: 1
  title: MyString
  published_on: 2012-12-06
  tags: MyText
  language: MyString

Apparently, something is missing and the document cannot be saved. But how do I find out what exactly is missing? Is there any advanced assertion method to do this?

And my model:

class Document < ActiveRecord::Base
  attr_accessible :language, :pdf, :pdf_file_name, :published_on, :tags, :title, :user_id

  # Validations
  validates_presence_of :language, :published_on, :tags, :title, :user
  validates_date :published_on, on_or_before: Date.current,
                                on_or_before_message: "must be today or earlier"
  validates :user_id, numericality: { only_integer: true, greater_than: 0 }
  validates :pdf, attachment_presence: true

  # Relations
  belongs_to :user

  # Paperclip
  has_attached_file :pdf
end

Answer 1

An easy way to find out why save fails is to call save! instead. The exception will give you enough information.

Another way is to call valid? and then puts errors.