Faking active_record classes

[elvanja]

I have issue with faking active record "where" method. An example:

class User < ActiveRecord::Base
end

class Task < ActiveRecord::Base
end

class ListTasks
  def initialize(user , task_repository = Task)
    @user = user
    @task_repository = task_repository
  end

  def all
    @task_repository.where(user_id: @user.id).order_by("priority asc")
  end
end

describe ListTasks do
  fake(:user, id: 100)
  fake(:task_repository) { Task }
  let(:subject) { described_class.new(user, task_repository) }

  it "fetches tasks for a given user" do
    subject.all
    expect(task_repository).to have_received.where(user_id: 100)
  end
end

Executing rspec gives:

Task:0x1d65a50 does not respond to where

I am using bogus v0.0.4.

[wrozka]

By default bogus fakes instances of classes, but here you need to fake the class, So you should create fake using:

fake(:task_repository, as: :class) { Task }

Here are the docs for faking classes.

[elvanja]

Great, that solved the issue, thank you for your time and a quick answer!

A side note: expect(task_repository).to have_received.where(user_id: 100) got me a bit confused since it is rather close to Test Spies in RSpec-Mocks. Just an observation.

[elvanja]

Found another problem, if you don't mind helping :-)

In another test I am trying to stub Task's user_id with a value, like this: stub(task).use_id { 666 }, and I get the following error:

Failure/Error: stub(task).user_id { stub.id { 101 } }
NameError: <Task:0x1ae24e0> does not respond to user_id

I've read the Bogus Safe Stubbing chapter, and here's what I wrote:

This time, the tasks belong to a user:

class User < ActiveRecord::Base
  has_many :tasks
end

class Task < ActiveRecord::Base
  belongs_to :user
end

class UpdateTask
  def initialize(user, task, task_repository = Task)
    ...
  end
end

describe UpdateTask do
  fake(:user)
  fake(:task)

  it "requires user and task user to match" do
      stub(user).id { 100 }
      stub(task).user_id { 101 }
      expect { described_class.new(user, task) }.to raise_error(ArgumentError)
  end
end

At the same time, stubbing the User property works just fine. The tests don't touch the database at all. Any idea why this is not working?

[wrozka]

Bogus doesn't handle methods defined on method_missing, as it would require calling respond_to? on the real instance. It copies only methods known at the fake creation. There is a workaround, that adds accessor methods for AR attributes based on schema,

[psyho]

Since the issue of stubbing fields on AR models seems tu come up pretty frequently, I added the workaround to the Bogus codebase.

[elvanja]

Yep, my bad, forgot about the way active record defines model methods. Was hoping I'd be able to avoid hitting the database :-( Anyway, thanks for the assistance!

[wrozka]

We've changed the mechanism for faking AR models a little. To avoid db interactions, you might consider using nulldb.