Testing before_filter gets called in action

Question

How would one test that when an action in controller is being accessed, that controller's before_filter will be executed?

The before_filter is tested in separate example group so that there's no need to duplicate the tests for all actions that depend on the before_filter.

If I have

controller.should_receive(:my_before_filter)

in my example, it works fine. However, having the above expectation seems to cause that the logic in my_before_filter is not being executed (it should assign an instance variable).

How to overcome this restriction or to mock behaviour of my_before_filter (it sets instance variable on controller)? Or is there some better way to do this?

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As it's now clear I was doing it all wrong, I'd still like to know how one could mock the behaviour of before_filter that sets an instance variable. Surely it must be a possible to do this in a controller spec?

Answer 1

RSpec's should_receive implies that you are expecting to receive the method, but as a mock method, so it does not actually call the real method, which is "my_before_filter" in this case.

http://axonflux.com/rspecs-shouldreceive-doesnt-ac

If my_before_filter is already tested in a separate test, as you say, you should not really care that the real one is being called.

So you should test the actual functionality in one test, and test that it is being called in another, as you are already doing.

Incidentally, if you need it to return a value, you can see "Return Values" on the following page.

http://rspec.info/documentation/mocks/message_expectations.html

Answer 2

Testing the filter is looking too closely at the implementation, IMO. You want to ensure that the instance variable assignment is happening, not whether it takes place within a filter or within an action -- test the outcome, not the implementation.