Calling a controllers method in another controller Ember

test is not technically a method, but an action or event. Use the send method instead:

this.get('controllers.account_info').send('test', arg1, arg2);

As per Ember documentation; create a property that lazily looks up another controller in the container. This can only be used when defining another controller.

legacy ember application example:

App.PostController = Ember.Controller.extend({
  accountInfo: Ember.inject.controller()


modern ember application example:

// in an ember app created with ember-cli
// below snippet would be the app/controllers/post.js file
import Ember from 'ember';
export default Ember.Controller.extend({
  appController: Ember.inject.controller('application')

You can find more documentation about Ember.inject here