Merge pull request #106 from annuhdo/update-doc-mockComponent

Update site's doc mockComponent()

Author: bvaughn

content/docs/addons-test-utils.md

@@ -112,6 +112,10 @@ mockComponent(
 
 Pass a mocked component module to this method to augment it with useful methods that allow it to be used as a dummy React component. Instead of rendering as usual, the component will become a simple `<div>` (or other tag if `mockTagName` is provided) containing any provided children.
 
+> Note:
+>
+> `mockComponent()` is a legacy API. We recommend using [shallow rendering](/docs/test-utils.html#shallow-rendering) or [jest.mock()](https://facebook.github.io/jest/docs/en/tutorial-react-native.html#mock-native-modules-using-jestmock) instead.
+
 * * *
 
 ### `isElement()`