Support error boundaries on ReactTestRenderer (#7558)

(cherry picked from commit 38f74bc)

src/renderers/testing/ReactTestReconcileTransaction.js

@@ -89,6 +89,19 @@ var Mixin = {
     return ReactUpdateQueue;
   },
 
+  /**
+   * Save current transaction state -- if the return value from this method is
+   * passed to `rollback`, the transaction will be reset to that state.
+   */
+  checkpoint: function() {
+    // reactMountReady is the our only stateful wrapper
+    return this.reactMountReady.checkpoint();
+  },
+
+  rollback: function(checkpoint) {
+    this.reactMountReady.rollback(checkpoint);
+  },
+
   /**
    * `PooledClass` looks for this, and will invoke this before allowing this
    * instance to be reused.

src/renderers/testing/__tests__/ReactTestRenderer-test.js

@@ -206,4 +206,42 @@ describe('ReactTestRenderer', function() {
     expect(log).toEqual([null]);
   });
 
+  it('supports error boundaries', function() {
+    class Angry extends React.Component {
+      render() {
+        throw new Error('Please, do not render me.');
+      }
+    }
+
+    class Boundary extends React.Component {
+      constructor(props) {
+        super(props);
+        this.state = {error: false};
+      }
+      render() {
+        if (!this.state.error) {
+          return (<div><button onClick={this.onClick}>ClickMe</button><Angry /></div>);
+        } else {
+          return (<div>Happy Birthday!</div>);
+        }
+      }
+      onClick() {
+        /* do nothing */
+      }
+      unstable_handleError() {
+        this.setState({error: true});
+      }
+    }
+
+    var EventPluginHub = require('EventPluginHub');
+    EventPluginHub.putListener = jest.fn();
+    var renderer = ReactTestRenderer.create(<Boundary />);
+    expect(renderer.toJSON()).toEqual({
+      type: 'div',
+      props: {},
+      children: ['Happy Birthday!'],
+    });
+    expect(EventPluginHub.putListener).not.toBeCalled();
+  });
+
 });