Add Test Files In create-react-app as a react til

README.md

@@ -10,7 +10,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 For a steady stream of TILs from a variety of rocketeers, checkout
 [til.hashrocket.com](https://til.hashrocket.com/).
 
-_651 TILs and counting..._
+_652 TILs and counting..._
 
 ---
 
@@ -461,6 +461,7 @@ _651 TILs and counting..._
 - [Quickly Search For A Component With React DevTools](react/quickly-search-for-a-component-with-react-devtools.md)
 - [Read Only Input Elements](react/read-only-input-elements.md)
 - [Rendering Multiple Nodes With Fragments](react/rendering-multiple-nodes-with-fragments.md)
+- [Test Files In create-react-app](react/test-files-in-create-react-app.md)
 - [Use A Ref To Autofocus An Input](react/use-a-ref-to-autofocus-an-input.md)
 - [Use withRouter To Pass Down React-Router History](react/use-withrouter-to-pass-down-react-router-history.md)
 - [Visually Select A React Element For Inspection](react/visually-select-a-react-element-for-inspection.md)

react/test-files-in-create-react-app.md

@@ -0,0 +1,14 @@
+# Test Files In create-react-app
+
+Any `.js` files placed in the `__tests__` directory will be treated as tests
+by Jest when running `yarn test`. If you don't want to place all of your
+files in that directory and especially if you want to co-located your test
+files with the source files, you can name them with the `.test.js` or
+`.spec.js` suffixes.
+
+Any files in your create-react-app project ending in these suffixes will be
+treated by Jest as test files and included in test runs.
+
+There are [more
+details](https://github.com/facebook/create-react-app/blob/master/packages/react-scripts/template/README.md#running-tests)
+in the docs.