diff --git a/core/modules/rest/src/Tests/Views/StyleSerializerTest.php b/core/modules/rest/src/Tests/Views/StyleSerializerTest.php
index 6e04d6b96e..53d038bb8d 100644
--- a/core/modules/rest/src/Tests/Views/StyleSerializerTest.php
+++ b/core/modules/rest/src/Tests/Views/StyleSerializerTest.php
@@ -373,12 +373,12 @@ public function testResponseFormatConfiguration() {
 
     // Should return a 406. Emulates a sample Firefox header.
     $this->drupalGet('test/serialize/field', [], ['Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8']);
-    $this->assertHeader('content-type', 'text/html; charset=UTF-8');
+    $this->assertHeader('content-type', 'text/plain; charset=UTF-8');
     $this->assertResponse(406, 'A 406 response was returned when a browser accept header was requested.');
 
     // Should return a 406.
     $this->drupalGetWithFormat('test/serialize/field', 'html');
-    $this->assertHeader('content-type', 'text/html; charset=UTF-8');
+    $this->assertHeader('content-type', 'text/plain; charset=UTF-8');
     $this->assertResponse(406, 'A 406 response was returned when HTML was requested.');
 
     // Should return a 200.
@@ -407,7 +407,7 @@ public function testResponseFormatConfiguration() {
     $this->assertResponse(200, 'A 200 response was returned when XML was requested');
     // Should return a 406 for HTML.
     $this->drupalGetWithFormat('test/serialize/field', 'html');
-    $this->assertHeader('content-type', 'text/html; charset=UTF-8');
+    $this->assertHeader('content-type', 'text/plain; charset=UTF-8');
     $this->assertResponse(406, 'A 406 response was returned when HTML was requested.');
   }
 
diff --git a/core/modules/views/src/Tests/Wizard/BasicTest.php b/core/modules/views/src/Tests/Wizard/BasicTest.php
index 7394991d23..245a0d1441 100644
--- a/core/modules/views/src/Tests/Wizard/BasicTest.php
+++ b/core/modules/views/src/Tests/Wizard/BasicTest.php
@@ -161,8 +161,9 @@ public function testViewsWizardAndListing() {
     $this->drupalPostForm('admin/structure/views/add', $view4, t('Save and edit'));
     $this->assertRaw(t('The view %view has been saved.', ['%view' => $view4['label']]));
 
-    // Check that the REST export path works.
-    $this->drupalGet($view4['rest_export[path]']);
+    // Check that the REST export path works. JSON will work, as all core
+    // formats will be allowed. JSON and XML by default.
+    $this->drupalGetJSON($view4['rest_export[path]']);
     $this->assertResponse(200);
     $data = Json::decode($this->content);
     $this->assertEqual(count($data), 1, 'Only the node of type page is exported.');