Tests to validate the flow of token already used

spec/controllers/users/confirmations_controller_spec.rb

@@ -9,5 +9,13 @@ describe Users::ConfirmationsController do
     it "returns a 404 code with a wrong token" do
       expect { get :show, params: { token: "non_existent" } }.to raise_error ActiveRecord::RecordNotFound
     end
+
+    it "redirect to sign_in page with a existent token " do
+      user = create(:user, confirmation_token: "token1")
+
+      get :show, params: { user: user, confirmation_token: "token1" }
+
+      expect(response).to redirect_to(new_user_session_path)
+    end
   end
 end