core/modules/rest/src/Tests/Views/StyleSerializerTest.php | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/core/modules/rest/src/Tests/Views/StyleSerializerTest.php b/core/modules/rest/src/Tests/Views/StyleSerializerTest.php
index 53d038b..6e04d6b 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/plain; charset=UTF-8');
+    $this->assertHeader('content-type', 'text/html; 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/plain; charset=UTF-8');
+    $this->assertHeader('content-type', 'text/html; 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/plain; charset=UTF-8');
+    $this->assertHeader('content-type', 'text/html; charset=UTF-8');
     $this->assertResponse(406, 'A 406 response was returned when HTML was requested.');
   }