diff --git a/core/modules/simpletest/src/TestBase.php b/core/modules/simpletest/src/TestBase.php
index 1e59712..acc8c81 100644
--- a/core/modules/simpletest/src/TestBase.php
+++ b/core/modules/simpletest/src/TestBase.php
@@ -754,9 +754,9 @@ protected function assertNotIdentical($first, $second, $message = '', $group = '
    *   TRUE if the assertion succeeded, FALSE otherwise.
    */
   protected function assertIdenticalObject($object1, $object2, $message = '', $group = 'Other') {
-    $message = $message ?: SafeMarkup::format('!object1 is identical to !object2', array(
-      '!object1' => var_export($object1, TRUE),
-      '!object2' => var_export($object2, TRUE),
+    $message = $message ?: SafeMarkup::format('@object1 is identical to @object2', array(
+      '@object1' => var_export($object1, TRUE),
+      '@object2' => var_export($object2, TRUE),
     ));
     $identical = TRUE;
     foreach ($object1 as $key => $value) {
diff --git a/core/modules/simpletest/src/WebTestBase.php b/core/modules/simpletest/src/WebTestBase.php
index 5e86826..cc16100 100644
--- a/core/modules/simpletest/src/WebTestBase.php
+++ b/core/modules/simpletest/src/WebTestBase.php
@@ -1419,12 +1419,12 @@ protected function curlExec($curl_options, $redirect = FALSE) {
     $this->url = isset($original_url) ? $original_url : curl_getinfo($this->curlHandle, CURLINFO_EFFECTIVE_URL);
 
     $message_vars = array(
-      '!method' => !empty($curl_options[CURLOPT_NOBODY]) ? 'HEAD' : (empty($curl_options[CURLOPT_POSTFIELDS]) ? 'GET' : 'POST'),
+      '@method' => !empty($curl_options[CURLOPT_NOBODY]) ? 'HEAD' : (empty($curl_options[CURLOPT_POSTFIELDS]) ? 'GET' : 'POST'),
       '@url' => isset($original_url) ? $original_url : $url,
       '@status' => $status,
-      '!length' => format_size(strlen($this->getRawContent()))
+      '@length' => format_size(strlen($this->getRawContent()))
     );
-    $message = SafeMarkup::format('!method @url returned @status (!length).', $message_vars);
+    $message = SafeMarkup::format('@method @url returned @status (@length).', $message_vars);
     $this->assertTrue($this->getRawContent() !== FALSE, $message, 'Browser');
     return $this->getRawContent();
   }
@@ -2716,7 +2716,7 @@ protected function assertUrl($path, array $options = array(), $message = '', $gr
   protected function assertResponse($code, $message = '', $group = 'Browser') {
     $curl_code = curl_getinfo($this->curlHandle, CURLINFO_HTTP_CODE);
     $match = is_array($code) ? in_array($curl_code, $code) : $curl_code == $code;
-    return $this->assertTrue($match, $message ? $message : SafeMarkup::format('HTTP response expected !code, actual !curl_code', array('!code' => $code, '!curl_code' => $curl_code)), $group);
+    return $this->assertTrue($match, $message ? $message : SafeMarkup::format('HTTP response expected @code, actual @curl_code', array('@code' => $code, '@curl_code' => $curl_code)), $group);
   }
 
   /**
@@ -2741,7 +2741,7 @@ protected function assertResponse($code, $message = '', $group = 'Browser') {
   protected function assertNoResponse($code, $message = '', $group = 'Browser') {
     $curl_code = curl_getinfo($this->curlHandle, CURLINFO_HTTP_CODE);
     $match = is_array($code) ? in_array($curl_code, $code) : $curl_code == $code;
-    return $this->assertFalse($match, $message ? $message : SafeMarkup::format('HTTP response not expected !code, actual !curl_code', array('!code' => $code, '!curl_code' => $curl_code)), $group);
+    return $this->assertFalse($match, $message ? $message : SafeMarkup::format('HTTP response not expected @code, actual @curl_code', array('@code' => $code, '@curl_code' => $curl_code)), $group);
   }
 
   /**