How to test exception raising in Rails/RSpec?

Question

There is the following code:

def index     @car_types = car_brand.car_types end  def car_brand     CarBrand.find(params[:car_brand_id])     rescue ActiveRecord::RecordNotFound         raise Errors::CarBrandNotFound.new  end 

I want to test it through RSpec. My code is:

it 'raises CarBrandNotFound exception' do     get :index, car_brand_id: 0     expect(response).to raise_error(Errors::CarBrandNotFound) end 

CarBrand with id equaling 0 doesn't exist, therefore my controller code raises Errors::CarBrandNotFound, but my test code tells me that nothing was raised. How can I fix it? What do I wrong?

Answer 1

In order to spec error handling, your expectations need to be set on a block; evaluating an object cannot raise an error.

So you want to do something like this:

expect {   get :index, car_brand_id: 0 }.to raise_error(Errors::CarBrandNotFound) 

See Expect error for details.

I am a bit surprised that you don't get any exception bubbling up to your spec results, though.