rails rspec matcher for exception with a stub method

Question

I am having trouble for the matcher to catch the exception. The controller method simply doing a REST call and get the fruit with the id and I want to test when REST give me an error respond which in rails is the JSON::ParserError. I want to test this case, so I stub out the REST call and raise the exception.

I know the fact that the stubbing work since I am getting that exact error. I believe that I just need a matcher to catch the error when calling the get

In Controller  

def show 
  @fruit = FruitsService::Client.get_fruit(params[:id])
end 

spec/controller/fruits_controller_spec.rb

describe '#show' do
  before do    
    context 'when a wrong id is given' do 
        FruitsService::Client.any_instance
          .stub(:get_fruit).with('wrong_id')
          .and_raise(JSON::ParserError)
  end

  it 'receives 404 error code' do 
    get :show, {id: 'wrong_id'}   <------ I think I might need a matcher for this ? 
    expect(FruitsService::Client.get_fruit('wrong_id')).to raise_error(JSON::ParserError)
  end

end 

This giving this

 Failure/Error: get :show, {id: 'wrong_id'}
 JSON::ParserError:
   JSON::ParserError

Answer 1

When you want to test behavior, such as the raising of errors, you need to pass a block to expect instead of a parameter, as in:

it 'receives 404 error code' do 
  expect { get :show, {id: 'wrong_id'} }.to raise_error(JSON::ParserError)
end