Stubbing ActiveRecord associations

Question

Say I have a Company which may contain many employees of type Employee may contain many tasks of type Task.

class Company < ActiveRecord::Base; has_many :employees; end
class Employee < ActiveRecord::Base; belongs_to :company, has_many :tasks; end
class Task < ActiveRecord::Base; belongs_to :employee; end

Using tools like FactoryGirl I may be tempted to create tasks using FactoryGirl.create(:task) forcing an employee and a company to be created as well.

What I want to do is to create valid ActiveRecord objects but with their relationships stubbed out so as to make my tests faster.

A solution I came up is to not use FactoryGirl and create the new objects using mock_model/stub_model to stub their associations.

Example:

employee = mock_model(Employee)
task = Task.create! name: "Do that", employee: employee

Am I doing it right?

Thanks.

Answer 1

If you don't want to create anything in the database you can do this:

employee = mock_model(Employee)
task = mock_model(Task, name: "Do that", employee: employee)

Keep in mind that you can't query them like that. It's roughly the same as building the object. If you ever want to do anything where you need to query actual data such as an integration test then you'll need use create to make stuff in the database. Or as one commenter pointed out, you can use FactoryGirl's methods to stub stuff out.

Answer 2

There is a distinct difference between mock_model and stub_model.

Assuming you're using RSpec, check out Mock Model and Stub Model.

Briefly though, the main difference is that mock_model is a true test double, that acts like an AR model. stub_model will create an instance of an actual AR model.

Either one of these options, along with Eric C's code snippet, is a good way to isolate your tests from the DB.