RN: Refactor `MockNativeMethods` in Jest

Reviewed By: sahrens

Differential Revision: D7917498

fbshipit-source-id: 97636080588bf2641a56256688cb0f2ec81ae463

jest/MockNativeMethods.js

@@ -0,0 +1,38 @@
+/**
+ * Copyright (c) 2013-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+'use strict';
+
+const mockNativeFunction = methodName => {
+  let warned = false;
+  return function() {
+    if (warned) {
+      return;
+    }
+    warned = true;
+    console.warn(
+      'Calling .' +
+        methodName +
+        '() in the test renderer environment is not supported. Instead, mock ' +
+        'out your components that use findNodeHandle with replacements that ' +
+        "don't rely on the native environment.",
+    );
+  };
+};
+
+const MockNativeMethods = {
+  measure: mockNativeFunction('measure'),
+  measureInWindow: mockNativeFunction('measureInWindow'),
+  measureLayout: mockNativeFunction('measureLayout'),
+  setNativeProps: mockNativeFunction('setNativeProps'),
+  focus: mockNativeFunction('focus'),
+  blur: mockNativeFunction('blur'),
+};
+
+module.exports = MockNativeMethods;

jest/setup.js

@@ -6,6 +6,7 @@
  */
 'use strict';
 
+const MockNativeMethods = require.requireActual('./MockNativeMethods');
 const mockComponent = require.requireActual('./mockComponent');
 
 require.requireActual('../Libraries/polyfills/babelHelpers.js');
@@ -81,33 +82,9 @@ jest
     const NativeMethodsMixin =
       ReactNative.__SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED.NativeMethodsMixin;
 
-    const mockFunction = (key) => {
+    Object.assign(NativeMethodsMixin, MockNativeMethods);
-      let warned = false;
+    Object.assign(ReactNative.NativeComponent.prototype, MockNativeMethods);
-      return function() {
-        if (warned) {
-          return;
-        }
-        warned = true;
-        console.warn(
-          'Calling .' + key + '() in the test renderer environment is not ' +
-            'supported. Instead, mock out your components that use ' +
-            'findNodeHandle with replacements that don\'t rely on the ' +
-            'native environment.',
-        );
-      };
-    };
 
-    [
-      'measure',
-      'measureInWindow',
-      'measureLayout',
-      'setNativeProps',
-      'focus',
-      'blur',
-    ].forEach((key) => {
-      NativeMethodsMixin[key] = mockFunction(key);
-      ReactNative.NativeComponent.prototype[key] = mockFunction(key);
-    });
     return ReactNative;
   })
   .mock('ensureComponentIsNative', () => () => true);