stub an instance variable inside controller

Question

I'm using rspec 1.3.2 to test a controller action that looks something like this:

def action_foo
  ...
  @bar.can_do_something?
  ...
end

I'm trying to stub @bar (assume it's an instance of class Bar) instance variable but am unable to. I think if I had access to any_instance then I could do Bar.any_instance.stub(:can_do_something?) but that's not available in the version of rspec I am using.

Is there another way to access and stub @bar? None of the following worked:

@bar.stub(:can_do_something?)
controller.instance_variable_get("@bar").stub(:can_do_something?)
controller.stub_chain(:bar, :can_do_something?)
Bar.new.stub(:can_do_something?)

Edit:

@bar is assigned in a before_filter. something like @bar = Bar.find(n)

Solution 1

For the record, this is a bit cleaner I think:

bar = Bar.new # or use FactoryGirl to create a Bar factory
bar.stub(:can_do_something?) { # return something }
controller.instance_variable_set(:@bar, bar)

Solution 2

 Bar.any_instance.stub(:can_do_something?)

Solution 3

If all else fails you could do something similar to any_instance.stub. For the record, this makes me feel dirty.

Bar.class_eval do
  alias :original_can_do_something? :can_do_something?

  def can_do_something?  # "stub" method
    # Return whatever you need here
  end
end

# Run your test

Bar.class_eval do
  alias :can_do_something? :original_can_do_something?  # "unstub" the method
end

Comments

[Dave Newton]

Where/how is @bar instantiated?

[Dty]

@bar is assigned in a before_filter

[Dty]

@bar is assigned in a before_filter

[apneadiving]

So do: Bar.should_receive(:find).and_return your_object_or_mock

[Dty]

i'm not going with this solution but accepting your answer since it's the only one that answered my question

[jibiel]

It's allow_any_instance_of(Bar).to receive(:can_do_something?).and_return true nowadays.