diff --git a/core/modules/update/src/Tests/UpdateUploadTest.php b/core/modules/update/src/Tests/UpdateUploadTest.php
index 4471c3a..92df4b5 100644
--- a/core/modules/update/src/Tests/UpdateUploadTest.php
+++ b/core/modules/update/src/Tests/UpdateUploadTest.php
@@ -127,17 +127,6 @@ public function testUploadModule() {
   }
 
   /**
-   * Ensures that archiver extensions are properly merged in the UI.
-   */
-  function testFileNameExtensionMerging() {
-    $this->drupalGet('admin/modules/install');
-    // Make sure the bogus extension supported by update_test.module is there.
-    $this->assertPattern('/file extensions are supported:.*update-test-extension/', "Found 'update-test-extension' extension.");
-    // Make sure it didn't clobber the first option from core.
-    $this->assertPattern('/file extensions are supported:.*tar/', "Found 'tar' extension.");
-  }
-
-  /**
    * Checks the messages on update manager pages when missing a security update.
    */
   function testUpdateManagerCoreSecurityUpdateMessages() {