Question

I have used have_db_column in other project, I don’t understand the undefined method error.
I also tried has_column

describe Notification do
  context "has valid db fields" do
    subject { Factory.build(:notification)}
    it { should be_valid }
    it { should have_db_column(:title)}
  end
end

mysql> describe notifications;
+---------------------+--------------+------+-----+---------+----------------+
| Field               | Type         | Null | Key | Default | Extra          |
+---------------------+--------------+------+-----+---------+----------------+
| id                  | int(11)      | NO   | PRI | NULL    | auto_increment |
| title               | varchar(255) | YES  |     | NULL    |                |

Factory.define :notification do |notification|
  notification.title {'test'}
end

Answer 1

It looks like you didn’t include shoulda matchers in your spec_helper.rb.