add testing environment

app/controllers/testing_accounts_controller.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+class TestingAccountsController < ApplicationController
+  skip_authorization_check only: :destroy
+
+  def show
+    authorize!(:manage, current_account)
+    authorize!(:manage, current_user)
+
+    impersonate_user(Accounts.find_or_create_testing_user(current_account))
+
+    redirect_back(fallback_location: root_path)
+  end
+
+  def destroy
+    stop_impersonating_user
+
+    redirect_back(fallback_location: root_path)
+  end
+end