diff --git a/core/modules/simpletest/tests/src/FunctionalJavascript/BrowserWithJavascriptTest.php b/core/modules/simpletest/tests/src/FunctionalJavascript/BrowserWithJavascriptTest.php
index dafe8e3..c856203 100644
--- a/core/modules/simpletest/tests/src/FunctionalJavascript/BrowserWithJavascriptTest.php
+++ b/core/modules/simpletest/tests/src/FunctionalJavascript/BrowserWithJavascriptTest.php
@@ -35,4 +35,27 @@ public function testJavascript() {
     $this->assertJsCondition($javascript);
   }
 
+  public function testAssertJsCondition() {
+    $this->drupalGet('<front>');
+    $session = $this->getSession();
+
+    $session->resizeWindow(500, 300);
+    $javascript = <<<JS
+    (function(){
+        var w = window,
+        d = document,
+        e = d.documentElement,
+        g = d.getElementsByTagName('body')[0],
+        x = w.innerWidth || e.clientWidth || g.clientWidth,
+        y = w.innerHeight || e.clientHeight|| g.clientHeight;
+        return x == 400 && y == 300;
+    }());
+JS;
+
+    // We expected the following assertion to fail because the window has been
+    // re-sized to have a width of 500 not 400.
+    $this->setExpectedException(\PHPUnit_Framework_AssertionFailedError::class);
+    $this->assertJsCondition($javascript, 100);
+  }
+
 }