forum/app/assets/javascripts/discourse/tests/acceptance/plugin-outlet-single-template-test.js

import { visit } from "@ember/test-helpers";
import { hbs } from "ember-cli-htmlbars";
import { test } from "qunit";
import { acceptance } from "discourse/tests/helpers/qunit-helpers";
import { registerTemporaryModule } from "../helpers/temporary-module-helper";

const CONNECTOR_MODULE =
  "discourse/theme-12/templates/connectors/user-profile-primary/hello";

acceptance("Plugin Outlet - Single Template", function (needs) {
  needs.hooks.beforeEach(() => {
    registerTemporaryModule(
      CONNECTOR_MODULE,
      hbs`<span class='hello-username'>{{this.model.username}}</span>`
    );
  });

  test("Renders a template into the outlet", async function (assert) {
    await visit("/u/eviltrout");
    assert.dom(".user-profile-primary-outlet").hasClass("hello");
    assert
      .dom(".hello-username")
      .hasText("eviltrout", "it renders into the outlet");
  });
});