diff --git a/src/vs/editor/test/browser/services/decorationRenderOptions.test.ts b/src/vs/editor/test/browser/services/decorationRenderOptions.test.ts
index 9608d1d779a..ef5cd93a887 100644
--- a/src/vs/editor/test/browser/services/decorationRenderOptions.test.ts
+++ b/src/vs/editor/test/browser/services/decorationRenderOptions.test.ts
@@ -125,7 +125,7 @@ suite('Decoration Render Options', () => {
 		if (platform.isWindows) {
 			// windows file path (used as string)
 			s.registerDecorationType('test', 'example', { gutterIconPath: URI.file('c:\\files\\miles\\more.png') });
-			assertBackground('file:///c:/files/miles/more.png', 'vscode-file://vscode-app/c:/files/miles/more.png');
+			assertBackground(CSS.escape('file:///c:/files/miles/more.png'), CSS.escape('vscode-file://vscode-app/c:/files/miles/more.png'));
 			s.removeDecorationType('example');
 
 			// single quote must always be escaped/encoded