Add validation for Ember.onerror in testing.

addon-test-support/ember-qunit/index.js

@@ -17,6 +17,7 @@ import {
   teardownRenderingContext,
   setupApplicationContext,
   teardownApplicationContext,
+  validateErrorHandler,
 } from '@ember/test-helpers';
 
 export function setupTest(hooks, options) {
@@ -127,6 +128,22 @@ export function setupEmberTesting() {
   });
 }
 
+/**
+  Ensures that `Ember.onerror` (if present) is properly configured to re-throw
+  errors that occur while `Ember.testing` is `true`.
+*/
+export function setupEmberOnerrorValidation() {
+  QUnit.module('ember-qunit: Ember.onerror validation', function() {
+    QUnit.test('Ember.onerror is functioning properly', function(assert) {
+      let result = validateErrorHandler();
+      assert.ok(
+        result.isValid,
+        `Ember.onerror handler with invalid testing behavior detected. An Ember.onerror handler _must_ rethrow exceptions when \`Ember.testing\` is \`true\` or the test suite is unreliable. See https://git.io/vbine for more details.`
+      );
+    });
+  });
+}
+
 /**
    @method start
    @param {Object} [options] Options to be used for enabling/disabling behaviors
@@ -140,6 +157,8 @@ export function setupEmberTesting() {
    @param {Boolean} [options.setupEmberTesting] `false` opts out of the
    default behavior of setting `Ember.testing` to `true` before all tests and
    back to `false` after each test will.
+   @param {Boolean} [options.setupEmberOnerrorValidation] If `false` validation
+   of `Ember.onerror` will be disabled.
  */
 export function start(options = {}) {
   if (options.loadTests !== false) {
@@ -158,6 +177,10 @@ export function start(options = {}) {
     setupEmberTesting();
   }
 
+  if (options.setupEmberOnerrorValidation !== false) {
+    setupEmberOnerrorValidation();
+  }
+
   if (options.startTests !== false) {
     startTests();
   }

tests/unit/setup-ember-onerror-validation-test.js

@@ -0,0 +1,26 @@
+import Ember from 'ember';
+import { module } from 'qunit';
+import { setupEmberOnerrorValidation } from 'ember-qunit';
+
+module('setupEmberOnerrorValidation', function(hooks) {
+  hooks.beforeEach(function(assert) {
+    let originalPushResult = assert.pushResult;
+    assert.pushResult = function(resultInfo) {
+      // Inverts the result so we can test failing assertions
+      resultInfo.result = !resultInfo.result;
+      resultInfo.message = `Failed: ${resultInfo.message}`;
+      originalPushResult(resultInfo);
+    };
+
+    this.originalEmberOnerror = Ember.onerror;
+    Ember.onerror = function() {
+      // intentionally swallowing here
+    };
+  });
+
+  hooks.afterEach(function() {
+    Ember.onerror = this.originalEmberOnerror;
+  });
+
+  setupEmberOnerrorValidation();
+});