diff --git a/tests/phpunit/tests/link.php b/tests/phpunit/tests/link.php
index b9576a7a1a16a..ceb12d0c3900d 100644
--- a/tests/phpunit/tests/link.php
+++ b/tests/phpunit/tests/link.php
@@ -150,8 +150,6 @@ public function test_unattached_attachment_has_a_pretty_permalink() {
 	 * @ticket 1914
 	 */
 	public function test_attachment_attached_to_non_existent_post_type_has_a_pretty_permalink() {
-		global $wp_post_types;
-
 		$this->set_permalink_structure( '/%year%/%monthnum%/%day%/%postname%/' );
 
 		register_post_type( 'not_a_post_type', array( 'public' => true ) );
@@ -175,12 +173,7 @@ public function test_attachment_attached_to_non_existent_post_type_has_a_pretty_
 
 		$this->assertSame( get_permalink( $post_id ) . user_trailingslashit( $attachment->post_name ), get_permalink( $attachment_id ) );
 
-		foreach ( $wp_post_types as $id => $pt ) {
-			if ( 'not_a_post_type' === $pt->name ) {
-				unset( $wp_post_types[ $id ] );
-				break;
-			}
-		}
+		unregister_post_type( 'not_a_post_type' );
 
 		$this->assertSame( home_url( "/?attachment_id={$attachment->ID}" ), get_permalink( $attachment_id ) );
 		// Visit permalink.