diff --git a/tests/php/SubsiteXHRControllerTest.php b/tests/php/SubsiteXHRControllerTest.php
index ba6549d..671bb57 100644
--- a/tests/php/SubsiteXHRControllerTest.php
+++ b/tests/php/SubsiteXHRControllerTest.php
@@ -35,7 +35,7 @@ class SubsiteXHRControllerTest extends FunctionalTest
         ]);
 
         $this->assertEquals(200, $result->getStatusCode());
-        $this->assertEquals('text/json', $result->getHeader('Content-Type'));
+        $this->assertEquals('application/json', $result->getHeader('Content-Type'));
 
         $body = $result->getBody();
         $this->assertContains('Main site', $body);