Ember {{assert}} helper

app\helpers\assert.js

import { helper } from '@ember/component/helper';
import { assert } from '@ember/debug';

/**
 * Verify that a certain expectation is met, or throw a exception
 * otherwise.
 *
 * Delegates directly to `assert` from `@ember/debug`.
 *
 * @param {string} description - Describes the expectation. This will
 *     become the text of the Error thrown if the assertion fails.
 * @param {boolean} condition - Must be truthy for the assertion to
 *     pass. If falsy, an exception will be thrown.
 *
 * @example
 * {{assert "Please pass @someRequiredArg" @someRequiredArg}}
 * @example
 * {{assert "Please ensure @amount is greater than 0" (gt @amount 0)}}
 */
export default helper(([description, condition]) => {
  assert(description, condition);
});

tests\integration\helpers\assert-test.js

import { module, test } from 'qunit';
import { setupRenderingTest } from 'ember-qunit';
import { render, setupOnerror } from '@ember/test-helpers';
import hbs from 'htmlbars-inline-precompile';

module('Integration | Helper | assert', function(hooks) {
  setupRenderingTest(hooks);

  test('performs an assertion', async function(assert) {
    const errors = [];

    setupOnerror(e => errors.push(e));

    await render(hbs`
      {{assert "Please set this.foo" this.foo}}
    `);

    assert.deepEqual(
      errors.map(e => e.message),
      ['Assertion Failed: Please set this.foo']
    );
  });
});