LayoutTests/fast/text/system-font-fallback.html - WebKit - Git at Google

 <!DOCTYPE html>
 <html>
 <head>
 </head>
 <body>
 This test makes sure that "system-ui" is expanded to every item in the platform fallback list. The test passes if all the lines below are rendered in the same font and identical.
 <div style="font-size: 100px;">
 <div style="font-family: 'system-ui'            ;">&#xE01;&#xE02;&#xE03;&#xE04;&#xE05;&#xE06;&#xE07;</div>
 <div style="font-family: 'system-ui', 'Thonburi';">&#xE01;&#xE02;&#xE03;&#xE04;&#xE05;&#xE06;&#xE07;</div>
 <div style="font-family: 'system-ui', 'Ayuthaya';">&#xE01;&#xE02;&#xE03;&#xE04;&#xE05;&#xE06;&#xE07;</div>
 </div>
 </body>
 </html>
	<!DOCTYPE html>
	<html>
	<head>
	</head>
	<body>
	This test makes sure that "system-ui" is expanded to every item in the platform fallback list. The test passes if all the lines below are rendered in the same font and identical.
	<div style="font-size: 100px;">
	<div style="font-family: 'system-ui' ;">กขฃคฅฆง</div>
	<div style="font-family: 'system-ui', 'Thonburi';">กขฃคฅฆง</div>
	<div style="font-family: 'system-ui', 'Ayuthaya';">กขฃคฅฆง</div>
	</div>
	</body>
	</html>