diff --git a/Libraries/Utilities/__mocks__/PixelRatio.js b/Libraries/Utilities/__mocks__/PixelRatio.js
index bcf04d7fe..6e16eddf1 100644
--- a/Libraries/Utilities/__mocks__/PixelRatio.js
+++ b/Libraries/Utilities/__mocks__/PixelRatio.js
@@ -1,20 +1,24 @@
 /**
  * Copyright 2004-present Facebook. All Rights Reserved.
  */
+
 'use strict';
 
-var PixelRatio = {
-  startDetecting: function () {
-    // noop for our implementation
-  },
-
-  get: function() {
-    return 2;
-  },
-
-  getPixelSizeForLayoutSize: function (layoutSize) {
-    return Math.round(layoutSize * PixelRatio.get());
-  }
+const PixelRatio = {
+  get: jest.genMockFunction().mockReturnValue(2),
+  getFontScale: jest.genMockFunction().mockImplementation(
+    () => PixelRatio.get()
+  ),
+  getPixelSizeForLayoutSize: jest.genMockFunction().mockImplementation(
+    layoutSize => Math.round(layoutSize * PixelRatio.get())
+  ),
+  roundToNearestPixel: jest.genMockFunction().mockImplementation(
+    layoutSize => {
+      const ratio = PixelRatio.get();
+      return Math.round(layoutSize * ratio) / ratio;
+    }
+  ),
+  startDetecting: jest.genMockFunction(),
 };
 
 module.exports = PixelRatio;