diff --git a/core/modules/simpletest/src/AssertContentTrait.php b/core/modules/simpletest/src/AssertContentTrait.php
index eb1a80c..b5d3b4f 100644
--- a/core/modules/simpletest/src/AssertContentTrait.php
+++ b/core/modules/simpletest/src/AssertContentTrait.php
@@ -527,6 +527,18 @@ protected function assertNoEscaped($raw, $message = '', $group = 'Other') {
     return $this->assert(strpos($this->getRawContent(), Html::escape($raw)) === FALSE, $message, $group);
   }
 
+
+  /**
+   * Temporary assert.
+   * @param $raw
+   * @param $out
+   * @return mixed
+   */
+  protected function assertNotEscaped($raw, $out) {
+    $message = 'ESCAPÉ "' . Html::escape($raw) . '" NOT FOUND';
+    return $this->assert(strpos($out, Html::escape($raw)) === FALSE, $message, $group = 'Other');
+  }
+
   /**
    * Passes if the page (with HTML stripped) contains the text.
    *
diff --git a/core/modules/simpletest/src/WebTestBase.php b/core/modules/simpletest/src/WebTestBase.php
index c890beb..4828faa 100644
--- a/core/modules/simpletest/src/WebTestBase.php
+++ b/core/modules/simpletest/src/WebTestBase.php
@@ -1548,6 +1548,8 @@ protected function drupalGet($path, array $options = array(), array $headers = a
     $verbose .= '<hr />' . $out;
 
     $this->verbose($verbose);
+    $this->assertNoEscaped('&lt;', $out);
+    $this->assertNoEscaped('&amp;', $out);
     return $out;
   }
 
@@ -1781,6 +1783,8 @@ protected function drupalPostForm($path, $edit, $submit, array $options = array(
           $verbose .= '<hr />' . $out;
 
           $this->verbose($verbose);
+          $this->assertNotEscaped('&lt;', $out);
+          $this->assertNotEscaped('&amp;', $out);
           return $out;
         }
       }
@@ -2084,7 +2088,7 @@ protected function drupalProcessAjaxResponse($content, array $ajax_response, arr
    * @see WebTestBase::curlExec()
    */
   protected function drupalPost($path, $accept, array $post, $options = array()) {
-    return $this->curlExec(array(
+    $out = $this->curlExec(array(
       CURLOPT_URL => $this->buildUrl($path, $options),
       CURLOPT_POST => TRUE,
       CURLOPT_POSTFIELDS => $this->serializePostValues($post),
@@ -2093,6 +2097,10 @@ protected function drupalPost($path, $accept, array $post, $options = array()) {
         'Content-Type: application/x-www-form-urlencoded',
       ),
     ));
+
+    $this->assertNotEscaped('&lt;', $out);
+    $this->assertNotEscaped('&amp;', $out);
+    return $out;
   }
 
   /**