Daikini

I’ve written a couple test helpers that I’ve found to be pretty useful when testing ActiveRecord validations. Just add them to your RAILS_ROOT/test/test_helper.rb file.

The assert_errors_on method takes an object and a hash of attributes and the validation errors that they should have.

The assert_no_errors_on method takes an object and a list of attributes that should not have any validation errors.

   1  def assert_errors_on(object, errors = {})
   2    assert !object.valid?
   3    errors.each do |attribute, error| 
   4      assert_equal error.to_a.sort, object.errors.on(attribute).to_a.sort, "Error on #{attribute}" 
   5    end
   6  end
   7    
   8  def assert_no_errors_on(object, *attributes)
   9    object.valid?
  10    attributes.each { |attribute| assert_nil object.errors.on(attribute), "Error on #{attribute}" }
  11  end

You can then use them like this:

   1  require File.dirname(__FILE__) + '/../test_helper'
   2  
   3  class PersonTest < Test::Unit::TestCase
   4    def test_should_require_unique_email_address
   5      # Using assert_errors_on method
   6      person = Person.new :email_address => "cosmo@sprockets.com"
   7      assert_errors_on person, :email_address => "has already been taken"
   8  
   9      # Doing the same thing but without the assert_errors_on method
  10      person = Person.new :email_address => "cosmo@sprockets.com"
  11      assert !person.valid?
  12      assert_equal "has already been taken", person.errors.on(:email_address)
  13  
  14      # Using assert_no_errors on method
  15      person = Person.new :email_address => "john.smith@example.com"
  16      assert_no_errors_on person, :email_address
  17      
  18      # Doing the same thing but without the assert_no_errors_on method
  19      person = Person.new :email_address => "john.smith@example.com"
  20      person.valid?
  21      assert_nil person.errors.on(:email_address)
  22    end
  23  
  24    # We can test other attributes independently as well
  25  
  26    def test_should_require_a_first_name
  27      person = Person.new
  28      assert_errors_on person, :first_name => "can't be blank"
  29  
  30      person = Person.new :first_name => "Jonathan"
  31      assert_no_errors_on :person, :first_name
  32    end
  33  
  34    def test_should_require_a_last_name
  35      person = Person.new
  36      assert_errors_on person, :last_name => "can't be blank"
  37  
  38      person = Person.new :last_name => "Younger"
  39      assert_no_errors_on :person, :last_name
  40    end
  41  
  42    def test_should_blah_blah_blah
  43      ...
  44    end
  45  end

Updated 2007-11-28: Added additional attribute tests to show that the attributes can be tested in isolation without regards to ensuring that all of the attributes have to be valid for testing to work.

Updated 2007-09-14: Added code for showing what the tests would look like by not using the test helpers.