Add spec to features/admin/products_spec from spre_auth_devise

spec/features/admin/products_spec.rb

@@ -17,6 +17,12 @@ feature '
     @enterprise_fees = (0..2).map { |i| create(:enterprise_fee, enterprise: @distributors[i]) }
   end
 
+  context "as anonymous user" do
+    it "is redirected to login page when attempting to access product listing" do
+      expect { visit spree.admin_products_path }.not_to raise_error
+    end
+  end
+
   describe "creating a product" do
     let!(:tax_category) { create(:tax_category, name: 'Test Tax Category') }