diff --git a/core/modules/responsive_image/src/Tests/ResponsiveImageFieldDisplayTest.php b/core/modules/responsive_image/src/Tests/ResponsiveImageFieldDisplayTest.php
index 53b83c2..ccc09be 100644
--- a/core/modules/responsive_image/src/Tests/ResponsiveImageFieldDisplayTest.php
+++ b/core/modules/responsive_image/src/Tests/ResponsiveImageFieldDisplayTest.php
@@ -351,7 +351,7 @@ public function testResponsiveImageFieldFormattersEmptyMediaQuery() {
     $this->drupalGet('node/' . $nid);
 
     // Assert an empty media attribute is not output.
-    $this->assertNoPattern('@srcset="data:image/gif;base64,R0lGODlhAQABAIABAP///wAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw== 1x".+?media="@');
+    $this->assertNoPattern('@srcset="data:image/gif;base64,R0lGODlhAQABAIABAP///wAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw== 1x".+?media=".+?/><source@');
 
     // Assert the media attribute is present if it has a value.
     $thumbnail_style = ImageStyle::load('thumbnail');