fix: make <Link> inert for setupRenderingTest

addon/components/link/component.ts

@@ -1,3 +1,4 @@
+import { assert } from '@ember/debug';
 import { action } from '@ember/object';
 import { reads } from '@ember/object/computed';
 import Transition from '@ember/routing/-private/transition';
@@ -57,6 +58,17 @@ export default class LinkComponent extends Component<LinkArgs> {
   @service
   private router!: RouterService;
 
+  /**
+   * Whether the router has been initialized. This will be false in render
+   * tests.
+   *
+   * @see https://github.com/buschtoens/ember-link/issues/126
+   */
+  private get isRouterInitialized() {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    return Boolean((this.router as any)._router._routerMicrolib);
+  }
+
   @reads('router.currentURL')
   private currentURL!: string;
 
@@ -97,6 +109,7 @@ export default class LinkComponent extends Component<LinkArgs> {
    * attribute.
    */
   get href(): string {
+    if (!this.isRouterInitialized) return '';
     return this.router.urlFor(...this.routeArgs);
   }
 
@@ -105,6 +118,7 @@ export default class LinkComponent extends Component<LinkArgs> {
    * models and query params.
    */
   get isActive(): boolean {
+    if (!this.isRouterInitialized) return false;
     this.currentURL; // eslint-disable-line no-unused-expressions
     return this.router.isActive(...this.routeArgs);
   }
@@ -114,6 +128,7 @@ export default class LinkComponent extends Component<LinkArgs> {
    * models, but ignoring query params.
    */
   get isActiveWithoutQueryParams() {
+    if (!this.isRouterInitialized) return false;
     this.currentURL; // eslint-disable-line no-unused-expressions
     return this.router.isActive(
       this.args.route,
@@ -130,6 +145,7 @@ export default class LinkComponent extends Component<LinkArgs> {
    * params.
    */
   get isActiveWithoutModels() {
+    if (!this.isRouterInitialized) return false;
     this.currentURL; // eslint-disable-line no-unused-expressions
     return this.router.isActive(this.args.route);
   }
@@ -139,8 +155,15 @@ export default class LinkComponent extends Component<LinkArgs> {
    */
   @action
   transitionTo(event?: Event | unknown): Transition {
+    // Intentionally putting this *before* the assertion to prevent navigating
+    // away in case of a failed assertion.
     this.preventDefault(event);
 
+    assert(
+      'You can only call `transitionTo`, when the router is initialized, e.g. when using `setupApplicationTest`.',
+      this.isRouterInitialized
+    );
+
     return this.router.transitionTo(...this.routeArgs);
   }
 
@@ -150,8 +173,15 @@ export default class LinkComponent extends Component<LinkArgs> {
    */
   @action
   replaceWith(event?: Event | unknown): Transition {
+    // Intentionally putting this *before* the assertion to prevent navigating
+    // away in case of a failed assertion.
     this.preventDefault(event);
 
+    assert(
+      'You can only call `replaceWith`, when the router is initialized, e.g. when using `setupApplicationTest`.',
+      this.isRouterInitialized
+    );
+
     return this.router.replaceWith(...this.routeArgs);
   }
 

tests/helpers/wait-for-error.ts

@@ -0,0 +1,47 @@
+import { waitUntil } from '@ember/test-helpers';
+
+import Ember from 'ember';
+
+import { on, off } from 'rsvp';
+
+/**
+ * I would be using `ember-qunit-assert-helpers` here, but it does not work with
+ * async rendering. :(
+ *
+ * Adapted from https://github.com/workmanw/ember-qunit-assert-helpers/issues/18#issuecomment-390003905
+ */
+export default async function waitForError(
+  callback: () => Promise<unknown>,
+  options?: Parameters<typeof waitUntil>[1]
+) {
+  const originalEmberListener = Ember.onerror;
+  const originalWindowListener = window.onerror;
+
+  let error: Error | undefined;
+  Ember.onerror = uncaughtError => {
+    error = uncaughtError;
+  };
+  window.onerror = (
+    _message,
+    _source,
+    _lineNumber,
+    _columnNumber,
+    uncaughtError
+  ) => {
+    error = uncaughtError;
+  };
+  on('error', Ember.onerror);
+
+  await Promise.all([
+    waitUntil(() => error, options).finally(() => {
+      Ember.onerror = originalEmberListener;
+      window.onerror = originalWindowListener;
+      off('error', Ember.onerror);
+    }),
+    callback()
+  ]);
+
+  if (!error) throw new Error('No Error was thrown.');
+
+  return error;
+}

tests/integration/components/link-test.ts

@@ -0,0 +1,52 @@
+import { render, click } from '@ember/test-helpers';
+import { setupRenderingTest } from 'ember-qunit';
+import { module, test } from 'qunit';
+
+import hbs from 'htmlbars-inline-precompile';
+
+import waitForError from 'dummy/tests/helpers/wait-for-error';
+
+module('Integration | Component | link', function(hooks) {
+  setupRenderingTest(hooks);
+
+  // Regression for: https://github.com/buschtoens/ember-link/issues/126
+  test('it renders', async function(assert) {
+    await render(hbs`
+      <Link @route="foo" as |l|>
+        <a
+          data-test-link
+          href={{l.href}}
+          class={{if l.isActive "is-active"}}
+          {{on "click" l.transitionTo}}
+        >
+          Link
+        </a>
+      </Link>
+    `);
+
+    assert.dom('[data-test-link]').hasAttribute('href', '');
+    assert.dom('[data-test-link]').hasNoClass('is-active');
+  });
+
+  test('triggering a transition has no effect', async function(assert) {
+    await render(hbs`
+      <Link @route="foo" as |l|>
+        <a
+          data-test-link
+          href={{l.href}}
+          class={{if l.isActive "is-active"}}
+          {{on "click" l.transitionTo}}
+        >
+          Link
+        </a>
+      </Link>
+    `);
+
+    const error = await waitForError(() => click('[data-test-link]'));
+    assert.ok(error instanceof Error);
+    assert.strictEqual(
+      error.message,
+      'Assertion Failed: You can only call `transitionTo`, when the router is initialized, e.g. when using `setupApplicationTest`.'
+    );
+  });
+});