diff --git a/core/modules/rest/src/Tests/NodeTest.php b/core/modules/rest/src/Tests/NodeTest.php
index 4948900..b55cd0b 100644
--- a/core/modules/rest/src/Tests/NodeTest.php
+++ b/core/modules/rest/src/Tests/NodeTest.php
@@ -180,7 +180,7 @@ public function testInvalidBundle() {
 
     // Make sure the response is "Bad Request".
     $this->assertResponse(400);
-    $this->assertResponseBody('{"error":"\"bad_bundle_name\" is not a valid bundle type for denormalization."}');
+    $this->assertResponseBody(NULL, '{"error":"\"bad_bundle_name\" is not a valid bundle type for denormalization."}');
   }
 
   /**
@@ -197,6 +197,6 @@ public function testMissingBundle() {
 
     // Make sure the response is "Bad Request".
     $this->assertResponse(400);
-    $this->assertResponseBody('{"error":"A string must be provided as a bundle value."}');
+    $this->assertResponseBody(NULL, '{"error":"A string must be provided as a bundle value."}');
   }
 }
diff --git a/core/modules/rest/src/Tests/RESTTestBase.php b/core/modules/rest/src/Tests/RESTTestBase.php
index a2da3a7..4309e42 100644
--- a/core/modules/rest/src/Tests/RESTTestBase.php
+++ b/core/modules/rest/src/Tests/RESTTestBase.php
@@ -402,6 +402,10 @@ protected function removeNodeFieldsForNonAdminUsers(NodeInterface $node) {
    * Check to see if the HTTP request response body is identical to the expected
    * value.
    *
+   *
+   * @param $code
+   *   (optional) Response code. For example 200 is a successful page request. For a list
+   *   of all codes see http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html.
    * @param $expected
    *   The first value to check.
    * @param $message
@@ -418,7 +422,11 @@ protected function removeNodeFieldsForNonAdminUsers(NodeInterface $node) {
    * @return bool
    *   TRUE if the assertion succeeded, FALSE otherwise.
    */
-  protected function assertResponseBody($expected, $message = '', $group = 'REST Response') {
+  protected function assertResponseBody($code = NULL, $expected, $message = '', $group = 'REST Response') {
+    if ($code) {
+      $this->assertResponse($code);
+    }
     return $this->assertIdentical($expected, $this->responseBody, $message ? $message : strtr('Response body @expected (expected) is equal to @response (actual).', array('@expected' => var_export($expected, TRUE), '@response' => var_export($this->responseBody, TRUE))), $group);
   }
+
 }
diff --git a/core/modules/rest/src/Tests/UserLoginTest.php b/core/modules/rest/src/Tests/UserLoginTest.php
index 443d151..ffe00a3 100644
--- a/core/modules/rest/src/Tests/UserLoginTest.php
+++ b/core/modules/rest/src/Tests/UserLoginTest.php
@@ -39,58 +39,58 @@ public function testLogin() {
     $name = $account->getUsername();
     $pass = $account->pass_raw;
 
-    // Add registration permission to anonymous user.
+    // Add login permission to anonymous user.
     Role::load(RoleInterface::ANONYMOUS_ID)
       ->grantPermission('restful post user_login')
       ->save();
 
     $payload = array();
     $this->httpRequest('user_login', 'POST', json_encode($payload), 'application/json');
-    $this->assertResponse('400', 'No op found. Use: status, login, logout.');
+    $this->assertResponseBody('400', '{"error":"No op found. Use: status, login, logout."}');
 
     $payload = $this->getPayload('garbage');
     $this->httpRequest('user_login', 'POST', json_encode($payload), 'application/json');
-    $this->assertResponse('400', 'Unsupported op garbage.');
+    $this->assertResponseBody('400', '{"error":"Unsupported op garbage."}');
 
     $payload = $this->getPayload('status');
     $this->httpRequest('user_login', 'POST', json_encode($payload), 'application/json');
-    $this->assertResponse('200', 'You are logged in.');
+    $this->assertResponseBody('200', '"You are not logged in."');
 
     $payload = $this->getPayload('login');
     $this->httpRequest('user_login', 'POST', json_encode($payload), 'application/json');
-    $this->assertResponse('400', 'Missing credentials.');
+    $this->assertResponseBody('400', '{"error":"Missing credentials."}');
 
     $payload = $this->getPayload('login', $name);
     $this->httpRequest('user_login', 'POST', json_encode($payload), 'application/json');
-    $this->assertResponse('400', 'Missing credentials.pass.');
+    $this->assertResponseBody('400', '{"error":"Missing credentials.pass."}');
 
     $payload = $this->getPayload('login', NULL, $pass);
     $this->httpRequest('user_login', 'POST', json_encode($payload), 'application/json');
-    $this->assertResponse('400', 'Missing credentials.name.');
+    $this->assertResponseBody('400', '{"error":"Missing credentials.name."}');
 
     $payload = $this->getPayload('login', $name, 'garbage');
     $this->httpRequest('user_login', 'POST', json_encode($payload), 'application/json');
-    $this->assertResponse('400', 'Sorry, unrecognized username or password.');
+    $this->assertResponseBody('400', '{"error":"Sorry, unrecognized username or password."}');
 
     $payload = $this->getPayload('login', 'garbage', $pass);
     $this->httpRequest('user_login', 'POST', json_encode($payload), 'application/json');
-    $this->assertResponse('400', 'Sorry, unrecognized username or password.');
+    $this->assertResponseBody('400', '{"error":"Sorry, unrecognized username or password."}');
 
     $payload = $this->getPayload('login', $name, $pass);
     $this->httpRequest('user_login', 'POST', json_encode($payload), 'application/json');
-    $this->assertResponse('200', "You are logged in as $name.");
+    $this->assertResponseBody('200', '"You are logged in as ' . $name . '."');
 
     $payload = $this->getPayload('status');
     $this->httpRequest('user_login', 'POST', json_encode($payload), 'application/json');
-    $this->assertResponse('200', 'You are logged in.');
+    $this->assertResponseBody('200', '"You are logged in."');
 
     $payload = $this->getPayload('logout');
     $this->httpRequest('user_login', 'POST', json_encode($payload), 'application/json');
-    $this->assertResponse('200', 'You are logged out.');
+    $this->assertResponseBody('200', '"You are logged out."');
 
     $payload = $this->getPayload('status');
     $this->httpRequest('user_login', 'POST', json_encode($payload), 'application/json');
-    $this->assertResponse('200', 'You are logged out.');
+    $this->assertResponseBody('200', '"You are not logged in."');
 
   }