diff --git a/test/unit/src/core/Clock.tests.js b/test/unit/src/core/Clock.tests.js
index 6b2b1e030e0e777c3c78a50848b0cec009401e8d..75e388b6707055e4fd02c0b9df007b8e23f4c93b 100644
--- a/test/unit/src/core/Clock.tests.js
+++ b/test/unit/src/core/Clock.tests.js
@@ -8,7 +8,9 @@ export default QUnit.module( 'Core', () => {
 
 		function mockPerformance() {
 
-			self.performance = {
+			const reference = ( typeof global !== 'undefined' ) ? global : self;
+
+			reference.performance = {
 				deltaTime: 0,
 
 				next: function ( delta ) {
@@ -28,39 +30,39 @@ export default QUnit.module( 'Core', () => {
 		}
 
 		// INSTANCING
-		QUnit.todo( "Instancing", ( assert ) => {
+		QUnit.todo( 'Instancing', ( assert ) => {
 
-			assert.ok( false, "everything's gonna be alright" );
+			assert.ok( false, 'everything\'s gonna be alright' );
 
 		} );
 
 		// PUBLIC STUFF
-		QUnit.todo( "start", ( assert ) => {
+		QUnit.todo( 'start', ( assert ) => {
 
-			assert.ok( false, "everything's gonna be alright" );
+			assert.ok( false, 'everything\'s gonna be alright' );
 
 		} );
 
-		QUnit.todo( "stop", ( assert ) => {
+		QUnit.todo( 'stop', ( assert ) => {
 
-			assert.ok( false, "everything's gonna be alright" );
+			assert.ok( false, 'everything\'s gonna be alright' );
 
 		} );
 
-		QUnit.todo( "getElapsedTime", ( assert ) => {
+		QUnit.todo( 'getElapsedTime', ( assert ) => {
 
-			assert.ok( false, "everything's gonna be alright" );
+			assert.ok( false, 'everything\'s gonna be alright' );
 
 		} );
 
-		QUnit.todo( "getDelta", ( assert ) => {
+		QUnit.todo( 'getDelta', ( assert ) => {
 
-			assert.ok( false, "everything's gonna be alright" );
+			assert.ok( false, 'everything\'s gonna be alright' );
 
 		} );
 
 		// OTHERS
-		QUnit.test( "clock with performance", ( assert ) => {
+		QUnit.test( 'clock with performance', ( assert ) => {
 
 			if ( typeof performance === 'undefined' ) {
 
@@ -75,16 +77,16 @@ export default QUnit.module( 'Core', () => {
 
 			clock.start();
 
-			self.performance.next( 123 );
-			assert.numEqual( clock.getElapsedTime(), 0.123, "okay" );
+			performance.next( 123 );
+			assert.numEqual( clock.getElapsedTime(), 0.123, 'okay' );
 
-			self.performance.next( 100 );
-			assert.numEqual( clock.getElapsedTime(), 0.223, "okay" );
+			performance.next( 100 );
+			assert.numEqual( clock.getElapsedTime(), 0.223, 'okay' );
 
 			clock.stop();
 
-			self.performance.next( 1000 );
-			assert.numEqual( clock.getElapsedTime(), 0.223, "don't update time if the clock was stopped" );
+			performance.next( 1000 );
+			assert.numEqual( clock.getElapsedTime(), 0.223, 'don\'t update time if the clock was stopped' );
 
 		} );