From 159e28d4016c9ee535e0c29d7d68c5b46417d529 Mon Sep 17 00:00:00 2001
From: Justin Bay <justin.bay@outlook.com>
Date: Thu, 4 Jan 2018 20:20:43 -0500
Subject: [PATCH] align shallow renderer with other renderers in defaulting
 state to null on mount

---
 .../react-test-renderer/src/ReactShallowRenderer.js |  2 +-
 .../src/__tests__/ReactShallowRenderer-test.js      | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/packages/react-test-renderer/src/ReactShallowRenderer.js b/packages/react-test-renderer/src/ReactShallowRenderer.js
index ef50aafa28d1e..6c55709bca6b0 100644
--- a/packages/react-test-renderer/src/ReactShallowRenderer.js
+++ b/packages/react-test-renderer/src/ReactShallowRenderer.js
@@ -125,7 +125,7 @@ class ReactShallowRenderer {
   _mountClassComponent(props, context) {
     this._instance.context = context;
     this._instance.props = props;
-    this._instance.state = this._instance.state || emptyObject;
+    this._instance.state = this._instance.state || null;
     this._instance.updater = this._updater;
 
     if (typeof this._instance.componentWillMount === 'function') {
diff --git a/packages/react-test-renderer/src/__tests__/ReactShallowRenderer-test.js b/packages/react-test-renderer/src/__tests__/ReactShallowRenderer-test.js
index a2e572e7bd32a..fc76810aa1f27 100644
--- a/packages/react-test-renderer/src/__tests__/ReactShallowRenderer-test.js
+++ b/packages/react-test-renderer/src/__tests__/ReactShallowRenderer-test.js
@@ -947,4 +947,17 @@ describe('ReactShallowRenderer', () => {
     renderAndVerifyWarningAndError([], 'array');
     renderAndVerifyWarningAndError({}, 'object');
   });
+
+  it('should have initial state of null if not defined', () => {
+    class SomeComponent extends React.Component {
+      render() {
+        return <span />;
+      }
+    }
+
+    const shallowRenderer = createRenderer();
+    shallowRenderer.render(<SomeComponent />);
+
+    expect(shallowRenderer.getMountedInstance().state).toBeNull();
+  });
 });