Add test to prove ember-fetch@8 works with the current test-waiter system/integration

test-apps/ember-fetch-v8/public/test-file.json

@@ -0,0 +1,3 @@
+{
+  "greeting": "hello there!"
+}

test-apps/ember-fetch-v8/tests/ember-fetch-test.js

@@ -0,0 +1,19 @@
+import { module, test } from 'qunit';
+import { setupTest } from 'ember-qunit';
+import { settled } from '@ember/test-helpers';
+// this is bad, because fetch is actually ember-fetch, and we didn't install "fetch"
+import fetch from 'fetch';
+
+module('ember-fetch@8', function (hooks) {
+  setupTest(hooks);
+
+  test('it waits for the fetch to be done', async function (assert) {
+    const promise = fetch('test-file.json');
+
+    assert.strictEqual(promise._state, undefined);
+    assert.strictEqual(promise._result, undefined);
+    await settled();
+    assert.strictEqual(promise._state, 1);
+    assert.strictEqual(promise._result?.statusText, 'OK');
+  });
+});