diff --git a/test/all.js b/test/all.js
index 14c6897b197..2222c8995e9 100644
--- a/test/all.js
+++ b/test/all.js
@@ -49,6 +49,7 @@ function main() {
 		nodeMain: __filename,
 		baseUrl: path.join(path.dirname(__dirname), 'src'),
 		paths: {
+			'vs/css': '../test/css.mock',
 			'vs': `../${ out }/vs`,
 			'lib': `../${ out }/lib`,
 			'bootstrap': `../${ out }/bootstrap`
diff --git a/test/css.mock.js b/test/css.mock.js
new file mode 100644
index 00000000000..1829c6ae48e
--- /dev/null
+++ b/test/css.mock.js
@@ -0,0 +1,12 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+define([], function() {
+	return {
+		load: function(name, req, load) {
+			load({});
+		}
+	};
+});