should_accept_nested_attributes_for.rb

# Ensure that the model accepts nested attributes for association
#
# Example:
# should_accept_nested_attributes_for :orders
# 
def should_accept_nested_attributes_for(*associations)
  klass = model_class
  
  associations.each do |association|
    should "accept nested attributes for #{association}" do
      assert klass.new.respond_to?("#{association}_attributes="), "#{klass} does not accept nested attributes for association: #{association}"
    end
  end
end