How do I disable rescue handlers in Ruby on Rails apps when I'm running functional tests?

Question

I have a number of controllers in my Ruby on Rails apps with a rescue handler at the end of the action that basically catches any unhandled errors and returns some kind of "user friendly" error. However, when I'm doing rake test I'd like to have those default rescue handlers disabled so I can see the full error & stack trace. Is there any automated way to do this?

Update to clarify: I have an action like this:

def foo
  # do some stuff...
rescue
  render :text => "Exception: #{$!}" # this could be any kind of custom render
end

Now when I functional test this, if the exception is raised then I'm going to get just a little bit of info about the exception, but what I'd like is for it to act as though there's no rescue handler there, so I get the full debug information.

Update: SOLUTION

I did this:

  rescue:
    raise unless Rails.env.production?
    render :text => "Exception: #{$!}" # this could be any kind of custom render
  end

Biogenesis

Answer 1

Not quite automated, but how modifying your code to re-throw exceptions whenever called within a test?

Perhaps something like this:

def foo
  # do some stuff...
rescue
  raise if ENV["RAILS_ENV"] == "test"
  render :text => "Exception: #{$!}" # this could be any kind of custom render
end

Kindrakindred

raise if Rails.env.test? is cleaner IMO – Cascade

@Steven this doesn't really rescue only in production. It raises where it is.. but if you have 20 lines of code in the #do stuff then the raise gives no reference to this. The trace indicates the error occurred on the line that the raise is on. – Bunch

Actually, no. raise with no arguments re-raises the exception we just caught, keeping the stack trace intact. In other words, it would correctly indicate where the exception was originally raised and not the line raise if Rails.env.test? – Kindrakindred

Answer 2

Have you looked at using the assert_raise( exception1, exception2, ... ) { block } call and then printing the exception from the block?

Cascade

Answer 3

Which method are you using? There are two rescue methods in ActionController.

I have this in my base controller:

def rescue_action_in_public(exception)
    response_code = response_code_for_rescue(exception)
    status = interpret_status(response_code)
    respond_to do |format|
        format.html { render_optional_error_file response_code}
        format.js { render :update, :status => status  do |page| page.redirect_to(:url => error_page_url(status)) end}
end

end

This only displays custom errors in production mode.

Unfaithful

Why does it only run in production mode? I don't see that. – Biogenesis

Answer 4

I think the easiest thing to do is verify that the correct render was called-- or whatever was different from the regular, non-exceptional case.

Billington

Answer 5

You shouldn't need to disable your rescue block. Use the assert_raise method (as suggested by Scott), and in the block, call the method that you expect an exception from.

For example:

def test_throws_exception
  assert_raise Exception do
    raise_if_true(true)
  end
end

Baptist

I'm not trying to assert an exception, I know all about how do do that and have done it many times. I'm trying to get full information about exceptions that occur when I don't expect them (including stack trace) but only when I'm in test mode. – Biogenesis

Ah. Sorry. I misunderstood what you were trying to achieve. – Baptist