diff --git a/addon-test-support/ember-qunit/index.js b/addon-test-support/ember-qunit/index.js
index 1c463544..120a7b02 100644
--- a/addon-test-support/ember-qunit/index.js
+++ b/addon-test-support/ember-qunit/index.js
@@ -1,5 +1,7 @@
 export { default as moduleFor } from './legacy-2-x/module-for';
-export { default as moduleForComponent } from './legacy-2-x/module-for-component';
+export {
+  default as moduleForComponent,
+} from './legacy-2-x/module-for-component';
 export { default as moduleForModel } from './legacy-2-x/module-for-model';
 export { default as QUnitAdapter } from './adapter';
 export { module, test, skip, only, todo } from 'qunit';
@@ -25,6 +27,10 @@ import {
   teardownApplicationContext,
   validateErrorHandler,
 } from '@ember/test-helpers';
+import {
+  detectIfTestNotIsolated,
+  reportIfTestNotIsolated,
+} from './test-isolation-validation';
 
 export function setResolver() {
   deprecate(
@@ -164,7 +170,8 @@ export function setupTestContainer() {
   let params = QUnit.urlParams;
 
   let containerVisibility = params.nocontainer ? 'hidden' : 'visible';
-  let containerPosition = params.dockcontainer || params.devmode ? 'fixed' : 'relative';
+  let containerPosition =
+    params.dockcontainer || params.devmode ? 'fixed' : 'relative';
 
   if (params.devmode) {
     testContainer.className = ' full-screen';
@@ -175,7 +182,9 @@ export function setupTestContainer() {
 
   let qunitContainer = document.getElementById('qunit');
   if (params.dockcontainer) {
-    qunitContainer.style.marginBottom = window.getComputedStyle(testContainer).height;
+    qunitContainer.style.marginBottom = window.getComputedStyle(
+      testContainer
+    ).height;
   }
 }
 
@@ -228,6 +237,11 @@ export function setupEmberOnerrorValidation() {
   });
 }
 
+export function setupTestIsolationValidation() {
+  QUnit.testDone(detectIfTestNotIsolated);
+  QUnit.done(reportIfTestNotIsolated);
+}
+
 /**
    @method start
    @param {Object} [options] Options to be used for enabling/disabling behaviors
@@ -243,6 +257,8 @@ export function setupEmberOnerrorValidation() {
    back to `false` after each test will.
    @param {Boolean} [options.setupEmberOnerrorValidation] If `false` validation
    of `Ember.onerror` will be disabled.
+   @param {Boolean} [options.setupTestIsolationValidation] If `false` test isolation validation
+   will be disabled.
  */
 export function start(options = {}) {
   if (options.loadTests !== false) {
@@ -265,6 +281,13 @@ export function start(options = {}) {
     setupEmberOnerrorValidation();
   }
 
+  if (
+    typeof options.setupTestIsolationValidation !== 'undefined' &&
+    options.setupTestIsolationValidation !== false
+  ) {
+    setupTestIsolationValidation();
+  }
+
   if (options.startTests !== false) {
     startTests();
   }
diff --git a/addon-test-support/ember-qunit/test-isolation-validation.js b/addon-test-support/ember-qunit/test-isolation-validation.js
new file mode 100644
index 00000000..de8e52bd
--- /dev/null
+++ b/addon-test-support/ember-qunit/test-isolation-validation.js
@@ -0,0 +1,48 @@
+import { run } from '@ember/runloop';
+import { isSettled } from '@ember/test-helpers';
+
+const TESTS_NOT_ISOLATED = [];
+
+/**
+ * Detects if a specific test isn't isolated. A test is considered
+ * not isolated if it:
+ *
+ * - has no pending timers
+ * - is not in a runloop
+ * - has no pending AJAX requests
+ * - has no pending test waiters
+ *
+ * @function detectIfTestNotIsolated
+ * @param {Object} testInfo
+ * @param {string} testInfo.module The name of the test module
+ * @param {string} testInfo.name The test name
+ */
+export function detectIfTestNotIsolated({ module, name }) {
+  if (!isSettled()) {
+    TESTS_NOT_ISOLATED.push(`${module}: ${name}`);
+    run.cancelTimers();
+  }
+}
+
+/**
+ * Reports if a test isn't isolated. Please see above for what
+ * constitutes a test being isolated.
+ *
+ * @function reportIfTestNotIsolated
+ * @throws Error if tests are not isolated
+ */
+export function reportIfTestNotIsolated() {
+  if (TESTS_NOT_ISOLATED.length > 0) {
+    let leakyTests = TESTS_NOT_ISOLATED.slice();
+    TESTS_NOT_ISOLATED.length = 0;
+
+    throw new Error(getMessage(leakyTests.length, leakyTests.join('\n')));
+  }
+}
+
+export function getMessage(testCount, testsToReport) {
+  return `TESTS ARE NOT ISOLATED
+    The following (${testCount}) tests have one or more of pending timers, pending AJAX requests, pending test waiters, or are still in a runloop: \n
+    ${testsToReport}
+  `;
+}
diff --git a/testem.js b/testem.js
index 1993f327..03946afc 100644
--- a/testem.js
+++ b/testem.js
@@ -9,12 +9,15 @@ module.exports = {
     'Chrome'
   ],
   browser_args: {
-    Chrome: [
-      '--disable-gpu',
-      '--headless',
-      '--no-sandbox',
-      '--remote-debugging-port=9222',
-      '--window-size=1440,900'
-    ]
+    Chrome: {
+      mode: 'ci',
+      args: [
+        '--disable-gpu',
+        '--headless',
+        '--no-sandbox',
+        '--remote-debugging-port=9222',
+        '--window-size=1440,900'
+      ]
+    }
   }
 };
diff --git a/tests/unit/setup-test-isolation-validation.js b/tests/unit/setup-test-isolation-validation.js
new file mode 100644
index 00000000..bfe4f4bf
--- /dev/null
+++ b/tests/unit/setup-test-isolation-validation.js
@@ -0,0 +1,74 @@
+import Ember from 'ember';
+import { run } from '@ember/runloop';
+import { module, test } from 'qunit';
+import {
+  detectIfTestNotIsolated,
+  reportIfTestNotIsolated,
+  getMessage,
+} from 'ember-qunit/test-isolation-validation';
+
+module('setupTestIsolationValidation', function(hooks) {
+  hooks.beforeEach(function() {
+    this.cancelId = 0;
+
+    this._waiter = () => {
+      return !this.isWaiterPending;
+    };
+
+    // In Ember < 2.8 `registerWaiter` expected to be bound to
+    // `Ember.Test` 😭
+    //
+    // Once we have dropped support for < 2.8 we should swap this to
+    // use:
+    //
+    // import { registerWaiter } from '@ember/test';
+    Ember.Test.registerWaiter(this._waiter);
+  });
+
+  hooks.afterEach(function() {
+    Ember.Test.unregisterWaiter(this._waiter);
+
+    run.cancel(this.cancelId);
+  });
+
+  test('reportIfTestNotIsolated does not throw when test is isolated', function(assert) {
+    assert.expect(1);
+
+    detectIfTestNotIsolated({ module: 'foo', name: 'bar' });
+    reportIfTestNotIsolated();
+
+    assert.ok(true);
+  });
+
+  test('reportIfTestNotIsolated throws when test has pending timers', function(assert) {
+    assert.expect(1);
+
+    this.cancelId = run.later(() => {}, 10);
+
+    detectIfTestNotIsolated({ module: 'foo', name: 'bar' });
+
+    assert.throws(
+      function() {
+        reportIfTestNotIsolated();
+      },
+      Error,
+      getMessage(1, 'foo: bar')
+    );
+  });
+
+  test('reportIfTestNotIsolated throws when test has test waiters', function(assert) {
+    assert.expect(1);
+
+    this.isWaiterPending = true;
+
+    detectIfTestNotIsolated({ module: 'foo', name: 'bar' });
+
+    assert.throws(
+      function() {
+        reportIfTestNotIsolated();
+      },
+      Error,
+      getMessage(1, 'foo: bar')
+    );
+  });
+});