Index: tests/phpunit/tests/dependencies/scripts.php
===================================================================
--- tests/phpunit/tests/dependencies/scripts.php	(revision 46167)
+++ tests/phpunit/tests/dependencies/scripts.php	(working copy)
@@ -680,6 +680,7 @@
 		global $wp_scripts;
 
 		wp_default_scripts( $wp_scripts );
+		wp_default_packages( $wp_scripts );
 
 		$wp_scripts->base_url  = '';
 		$wp_scripts->do_concat = true;
@@ -705,6 +706,7 @@
 		global $wp_scripts;
 
 		wp_default_scripts( $wp_scripts );
+		wp_default_packages( $wp_scripts );
 
 		$wp_scripts->base_url  = '';
 		$wp_scripts->do_concat = true;
@@ -748,10 +750,8 @@
 		wp_enqueue_script( $handle, '/customize-dependency.js', array( 'customize-controls' ), null );
 		wp_add_inline_script( $handle, 'tryCustomizeDependency()' );
 
-		// Open a buffer to get the output of `wp_print_scripts`.
-		ob_start();
 		wp_print_scripts();
-		$print_scripts = ob_get_clean();
+		$print_scripts = get_echo( '_print_scripts' );
 
 		$tail = substr( $print_scripts, strrpos( $print_scripts, "<script type='text/javascript' src='/customize-dependency.js'>" ) );
 		$this->assertEquals( $expected_tail, $tail );