Avoiding Testem.hookIntoTestFramework() invocation with ember-qunit@5.0.0-beta.3+

[rwjblue]

As ember-qunit is progressing towards its 5.0.0 release, I'd like to ensure that it is compatible with Embroider. The goal of that release is to play nicely with the goals of Embroider. Some of the major changes there:

• Move qunit and @ember/test-helpers to be peerDependencies (along with validation that the app provides them)
• Remove usage of content-for to emit the DOM structure required for tests/index.html (instead have it included in the file normally)
• Avoid app.importing any JavaScript assets (including qunit itself and our custom configuration)

Part of the issue that we run into with the last item above is that qunit is no longer evaluated directly in the root of the test-support.js file, it is now in a module (by way of either ember-auto-import or Embroider magic). Unfortunately, both ember-cli and Embroider have baked in the assumption that by the end of test-support.js window.QUnit will be defined. This is no longer true as of ember-qunit@5.0.0-beta.3.

Specifically, the issue is in this Embroider code:

embroider/packages/core/src/app.ts

Lines 256 to 258 in 38a4030

	if (window.Testem) {
	window.Testem.hookIntoTestFramework();
	}`,

223e0cf (#752) is specifically working around this issue in a classic ember-cli build pipeline (by emitting a vendor/ember-cli/test-support-suffix.js that no longer contains the Testem.hookIntoTestFramework() invocation which clobbers the one provided by ember-cli itself). Obviously that work around doesn't work here (and its clearly haxxxors anyways).

[rwjblue]

#531 seems like the simplest fix (and one that I can land in ember-cli itself also), what do you think @ef4?