diff --git a/tests/qunit/ext.cite.referencePreviews/createReferenceGateway.test.js b/tests/qunit/ext.cite.referencePreviews/createReferenceGateway.test.js
index 3b29364c3..f906ef2cc 100644
--- a/tests/qunit/ext.cite.referencePreviews/createReferenceGateway.test.js
+++ b/tests/qunit/ext.cite.referencePreviews/createReferenceGateway.test.js
@@ -9,13 +9,12 @@ function createStubTitle( fragment = null ) {
 ( mw.loader.getModuleNames().indexOf( 'ext.popups.main' ) !== -1 ?
 	QUnit.module :
 	QUnit.module.skip )( 'ext.cite.referencePreviews#createReferenceGateway', {
-	beforeEach() {
-		// FIXME: Is this needed?
-		// global.CSS = {
-		// escape: ( str ) => $.escapeSelector( str )
-		// };
-		mw.msg = ( key ) => `<${ key }>`;
-		mw.message = ( key ) => ( { exists: () => !key.endsWith( 'generic' ), text: () => `<${ key }>` } );
+	beforeEach: function () {
+		this.sandbox.stub( mw, 'msg', ( key ) => `<${ key }>` );
+		this.sandbox.stub( mw, 'message', ( key ) => ( {
+			exists: () => !key.endsWith( 'generic' ),
+			text: () => `<${ key }>`
+		} ) );
 
 		this.$sourceElement = $( '<a>' ).appendTo(
 			$( '<sup>' ).attr( 'id', 'cite_ref-1' ).appendTo( document.body )
@@ -49,8 +48,6 @@ function createStubTitle( fragment = null ) {
 		).appendTo( document.body );
 	},
 	afterEach() {
-		mw.msg = null;
-		mw.message = null;
 		this.$sourceElement.parent().remove();
 		this.$references.remove();
 	}
diff --git a/tests/qunit/ext.cite.referencePreviews/renderer.test.js b/tests/qunit/ext.cite.referencePreviews/renderer.test.js
index 9375c9ea7..d20551019 100644
--- a/tests/qunit/ext.cite.referencePreviews/renderer.test.js
+++ b/tests/qunit/ext.cite.referencePreviews/renderer.test.js
@@ -7,18 +7,13 @@ const previewTypes = { TYPE_REFERENCE: 'reference' };
 	before() {
 		createReferencePreview = require( 'ext.cite.referencePreviews' ).private.createReferencePreview;
 	},
-	beforeEach() {
-		mw.msg = ( key ) => `<${ key }>`;
-		mw.message = ( key ) => ( { exists: () => !key.endsWith( 'generic' ), text: () => `<${ key }>` } );
-
-		mw.html = {
-			escape: ( str ) => str && str.replace( /'/g, '&apos;' ).replace( /</g, '&lt;' )
-		};
-	},
-	afterEach() {
-		mw.msg = null;
-		mw.message = null;
-		mw.html = null;
+	beforeEach: function () {
+		this.sandbox.stub( mw, 'msg', ( key ) => `<${ key }>` );
+		this.sandbox.stub( mw, 'message', ( key ) => ( {
+			exists: () => !key.endsWith( 'generic' ),
+			text: () => `<${ key }>`
+		} ) );
+		this.sandbox.stub( mw.html, 'escape', ( str ) => str && str.replace( /'/g, '&apos;' ).replace( /</g, '&lt;' ) );
 	}
 } );