test_404.rb

describe ExampleController, type: :controller do
  describe '#show' do
    context 'third party API returns 404' do
      before do
        stub_request(:get, "www.example.com").
          to_return(body: {error: "record not found"}.to_json, status: 404)
           
        get :show
      end
      
      it 'returns 200' do
        expect(response.status).to eq(200)
      end
      
      it 'returns correct error message' do
        expect(JSON.parse(response.body)).to eq({"error" => "record_not_found"})
      end
  end
end