diff --git a/src/browser/ui/__tests__/ReactDOMComponent-test.js b/src/browser/ui/__tests__/ReactDOMComponent-test.js
index de94aa62a8..f49941b132 100644
--- a/src/browser/ui/__tests__/ReactDOMComponent-test.js
+++ b/src/browser/ui/__tests__/ReactDOMComponent-test.js
@@ -351,7 +351,7 @@ describe('ReactDOMComponent', function() {
 
       var callback = function() {};
       var instance = <div onClick={callback} />;
-      React.renderComponent(instance, container);
+      instance = React.renderComponent(instance, container);
 
       var rootNode = instance.getDOMNode();
       var rootNodeID = ReactMount.getID(rootNode);
diff --git a/src/browser/ui/__tests__/ReactEventTopLevelCallback-test.js b/src/browser/ui/__tests__/ReactEventTopLevelCallback-test.js
index aeca33e6cc..03230cc357 100644
--- a/src/browser/ui/__tests__/ReactEventTopLevelCallback-test.js
+++ b/src/browser/ui/__tests__/ReactEventTopLevelCallback-test.js
@@ -44,8 +44,8 @@ describe('ReactEventTopLevelCallback', function() {
       var childControl = <div>Child</div>;
       var parentContainer = document.createElement('div');
       var parentControl = <div>Parent</div>;
-      ReactMount.renderComponent(childControl, childContainer);
-      ReactMount.renderComponent(parentControl, parentContainer);
+      childControl = ReactMount.renderComponent(childControl, childContainer);
+      parentControl = ReactMount.renderComponent(parentControl, parentContainer);
       parentControl.getDOMNode().appendChild(childContainer);
 
       var callback = ReactEventTopLevelCallback.createTopLevelCallback('test');
@@ -66,9 +66,9 @@ describe('ReactEventTopLevelCallback', function() {
       var parentControl = <div>Parent</div>;
       var grandParentContainer = document.createElement('div');
       var grandParentControl = <div>Parent</div>;
-      ReactMount.renderComponent(childControl, childContainer);
-      ReactMount.renderComponent(parentControl, parentContainer);
-      ReactMount.renderComponent(grandParentControl, grandParentContainer);
+      childControl = ReactMount.renderComponent(childControl, childContainer);
+      parentControl = ReactMount.renderComponent(parentControl, parentContainer);
+      grandParentControl = ReactMount.renderComponent(grandParentControl, grandParentContainer);
       parentControl.getDOMNode().appendChild(childContainer);
       grandParentControl.getDOMNode().appendChild(parentContainer);
 
@@ -90,8 +90,8 @@ describe('ReactEventTopLevelCallback', function() {
       var childControl = <div>Child</div>;
       var parentContainer = document.createElement('div');
       var parentControl = <div>Parent</div>;
-      ReactMount.renderComponent(childControl, childContainer);
-      ReactMount.renderComponent(parentControl, parentContainer);
+      childControl = ReactMount.renderComponent(childControl, childContainer);
+      parentControl = ReactMount.renderComponent(parentControl, parentContainer);
       parentControl.getDOMNode().appendChild(childContainer);
 
       // ReactEventEmitter.handleTopLevel might remove the target from the DOM.
diff --git a/src/browser/ui/dom/__tests__/CSSPropertyOperations-test.js b/src/browser/ui/dom/__tests__/CSSPropertyOperations-test.js
index cc5fcf37fa..6411adfebe 100644
--- a/src/browser/ui/dom/__tests__/CSSPropertyOperations-test.js
+++ b/src/browser/ui/dom/__tests__/CSSPropertyOperations-test.js
@@ -86,7 +86,7 @@ describe('CSSPropertyOperations', function() {
     };
     var div = <div style={styles} />;
     var root = document.createElement('div');
-    React.renderComponent(div, root);
+    div = React.renderComponent(div, root);
     expect(/style=".*"/.test(root.innerHTML)).toBe(true);
   });
 
diff --git a/src/browser/ui/dom/components/__tests__/ReactDOMButton-test.js b/src/browser/ui/dom/components/__tests__/ReactDOMButton-test.js
index b529f630d5..e9dbf98dd0 100644
--- a/src/browser/ui/dom/components/__tests__/ReactDOMButton-test.js
+++ b/src/browser/ui/dom/components/__tests__/ReactDOMButton-test.js
@@ -42,7 +42,7 @@ describe('ReactDOMButton', function() {
   }
 
   function mounted(button) {
-    ReactTestUtils.renderIntoDocument(button);
+    button = ReactTestUtils.renderIntoDocument(button);
     return button;
   }
 
diff --git a/src/core/__tests__/ReactComponent-test.js b/src/core/__tests__/ReactComponent-test.js
index 1899cfb7cc..f0fdf7f634 100644
--- a/src/core/__tests__/ReactComponent-test.js
+++ b/src/core/__tests__/ReactComponent-test.js
@@ -52,7 +52,7 @@ describe('ReactComponent', function() {
   it('should throw when supplying a ref outside of render method', function() {
     var instance = <div ref="badDiv" />;
     expect(function() {
-      ReactTestUtils.renderIntoDocument(instance);
+      instance = ReactTestUtils.renderIntoDocument(instance);
     }).toThrow();
   });
 
@@ -68,7 +68,7 @@ describe('ReactComponent', function() {
     var instance = <Component child={<span />} />;
 
     expect(function() {
-      ReactTestUtils.renderIntoDocument(instance);
+      instance = ReactTestUtils.renderIntoDocument(instance);
     }).toThrow(
       'Invariant Violation: attachRef(test, ...): Only a component\'s owner ' +
       'can store a ref to it.'
@@ -91,7 +91,7 @@ describe('ReactComponent', function() {
     });
 
     var instance = <Component child={<span />} />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
   });
 
   it('should not have refs on unmounted components', function() {
@@ -110,7 +110,7 @@ describe('ReactComponent', function() {
     });
 
     var instance = <Parent child={<span />} />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
   });
 
   it('should correctly determine if a component is mounted', function() {
@@ -146,7 +146,7 @@ describe('ReactComponent', function() {
     });
 
     var instance = <Owner />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     expect(instance._mountDepth).toBe(0);
     expect(instance.refs.child._mountDepth).toBe(1);
   });
@@ -197,7 +197,7 @@ describe('ReactComponent', function() {
     });
 
     var root = <App />;
-    ReactTestUtils.renderIntoDocument(root);
+    root = ReactTestUtils.renderIntoDocument(root);
 
     expect(root._mountDepth).toBe(0);
     expect(root.refs.switcher._mountDepth).toBe(1);
diff --git a/src/core/__tests__/ReactCompositeComponentDOMMinimalism-test.js b/src/core/__tests__/ReactCompositeComponentDOMMinimalism-test.js
index a1bd918a5f..cd2c9f11e7 100644
--- a/src/core/__tests__/ReactCompositeComponentDOMMinimalism-test.js
+++ b/src/core/__tests__/ReactCompositeComponentDOMMinimalism-test.js
@@ -78,7 +78,7 @@ describe('ReactCompositeComponentDOMMinimalism', function() {
         A string child
       </MyCompositeComponent>
     );
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     expectSingleChildlessDiv(instance);
   });
 
@@ -88,7 +88,7 @@ describe('ReactCompositeComponentDOMMinimalism', function() {
         {'Interpolated String Child'}
       </MyCompositeComponent>
     );
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     expectSingleChildlessDiv(instance);
   });
 
@@ -100,7 +100,7 @@ describe('ReactCompositeComponentDOMMinimalism', function() {
         </ul>
       </MyCompositeComponent>
     );
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     reactComponentExpect(instance)
       .expectRenderedChild()
       .toBeCompositeComponentWithType(LowerLevelComposite)
diff --git a/src/core/__tests__/ReactCompositeComponentError-test.js b/src/core/__tests__/ReactCompositeComponentError-test.js
index 35b17c0a5a..587ebe53f1 100644
--- a/src/core/__tests__/ReactCompositeComponentError-test.js
+++ b/src/core/__tests__/ReactCompositeComponentError-test.js
@@ -35,7 +35,7 @@ describe('ReactCompositeComponent-error', function() {
     });
 
     var instance = <Component />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     expect(ReactErrorUtils.guard.mostRecentCall.args[1])
       .toEqual('Component.someHandler');
   });
diff --git a/src/core/__tests__/ReactCompositeComponentMixin-test.js b/src/core/__tests__/ReactCompositeComponentMixin-test.js
index cc9c30b07c..482019ab57 100644
--- a/src/core/__tests__/ReactCompositeComponentMixin-test.js
+++ b/src/core/__tests__/ReactCompositeComponentMixin-test.js
@@ -103,7 +103,7 @@ describe('ReactCompositeComponent-mixin', function() {
   it('should support merging propTypes and statics', function() {
     var listener = mocks.getMockFunction();
     var instance = <TestComponent listener={listener} />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
 
     var instancePropTypes = instance.constructor.propTypes;
 
@@ -118,7 +118,7 @@ describe('ReactCompositeComponent-mixin', function() {
   it('should support chaining delegate functions', function() {
     var listener = mocks.getMockFunction();
     var instance = <TestComponent listener={listener} />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
 
     expect(listener.mock.calls).toEqual([
       ['MixinA didMount'],
diff --git a/src/core/__tests__/ReactCompositeComponentState-test.js b/src/core/__tests__/ReactCompositeComponentState-test.js
index b5dd6f48e6..fe9c6bff7d 100644
--- a/src/core/__tests__/ReactCompositeComponentState-test.js
+++ b/src/core/__tests__/ReactCompositeComponentState-test.js
@@ -109,7 +109,7 @@ describe('ReactCompositeComponent-state', function() {
   it('should support setting state', function() {
     var stateListener = mocks.getMockFunction();
     var instance = <TestComponent stateListener={stateListener} />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     instance.setProps({nextColor: 'green'});
     instance.setFavoriteColor('blue');
     instance.forceUpdate();
diff --git a/src/core/__tests__/ReactIdentity-test.js b/src/core/__tests__/ReactIdentity-test.js
index 1524c71d3a..1f7ba7be36 100644
--- a/src/core/__tests__/ReactIdentity-test.js
+++ b/src/core/__tests__/ReactIdentity-test.js
@@ -52,7 +52,7 @@ describe('ReactIdentity', function() {
         }}
       </div>;
 
-    React.renderComponent(instance, document.createElement('div'));
+    instance = React.renderComponent(instance, document.createElement('div'));
     var node = instance.getDOMNode();
     reactComponentExpect(instance).toBeDOMComponentWithChildCount(2);
     checkId(node.childNodes[0], '.0.$first:0');
@@ -68,7 +68,7 @@ describe('ReactIdentity', function() {
         <div key={123} />
       </div>;
 
-    React.renderComponent(instance, document.createElement('div'));
+    instance = React.renderComponent(instance, document.createElement('div'));
     var node = instance.getDOMNode();
     reactComponentExpect(instance).toBeDOMComponentWithChildCount(4);
     checkId(node.childNodes[0], '.0.$apple');
@@ -92,7 +92,7 @@ describe('ReactIdentity', function() {
         <Wrapper><span key="chipmunk" /></Wrapper>
       </div>;
 
-    React.renderComponent(instance, document.createElement('div'));
+    instance = React.renderComponent(instance, document.createElement('div'));
     var node = instance.getDOMNode();
     reactComponentExpect(instance).toBeDOMComponentWithChildCount(3);
 
@@ -282,7 +282,7 @@ describe('ReactIdentity', function() {
 
     var wrapped = <TestContainer first={instance0} second={instance1} />;
 
-    React.renderComponent(wrapped, document.createElement('div'));
+    wrapped = React.renderComponent(wrapped, document.createElement('div'));
 
     var beforeID = ReactMount.getID(wrapped.getDOMNode().firstChild);
 
diff --git a/src/core/__tests__/ReactPropTransferer-test.js b/src/core/__tests__/ReactPropTransferer-test.js
index b840b56352..4e20f84adc 100644
--- a/src/core/__tests__/ReactPropTransferer-test.js
+++ b/src/core/__tests__/ReactPropTransferer-test.js
@@ -48,7 +48,7 @@ describe('ReactPropTransferer', function() {
 
   it('should leave explicitly specified properties intact', function() {
     var instance = <TestComponent type="radio" />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
 
     reactComponentExpect(instance)
       .expectRenderedChild()
@@ -63,7 +63,7 @@ describe('ReactPropTransferer', function() {
 
   it('should transfer unspecified properties', function() {
     var instance = <TestComponent placeholder="Type here..." />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
 
     reactComponentExpect(instance)
       .expectRenderedChild()
@@ -77,7 +77,7 @@ describe('ReactPropTransferer', function() {
         className="hidden_elem"
         style={{width: '100%'}}
       />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
 
     reactComponentExpect(instance)
       .expectRenderedChild()
@@ -103,7 +103,7 @@ describe('ReactPropTransferer', function() {
         <span>Hello!</span>
       </ChildrenTestComponent>;
 
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     reactComponentExpect(instance)
       .expectRenderedChild()
         .toBeDOMComponentWithTag('div')
diff --git a/src/core/__tests__/ReactPropTypes-test.js b/src/core/__tests__/ReactPropTypes-test.js
index ece37be5c6..c5ca40cc2c 100644
--- a/src/core/__tests__/ReactPropTypes-test.js
+++ b/src/core/__tests__/ReactPropTypes-test.js
@@ -455,7 +455,7 @@ describe('Component Type', function() {
 
   it('should be able to define a single child as label', () => {
     var instance = <Component label={<div />} />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
 
     // No warnings should have been logged.
     expect(console.warn.mock.calls.length).toBe(0);
@@ -463,7 +463,7 @@ describe('Component Type', function() {
 
   it('should warn when passing no label and isRequired is set', () => {
     var instance = <Component />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
 
     expect(console.warn.mock.calls.length).toBe(1);
   });
diff --git a/src/core/__tests__/ReactStateSetters-test.js b/src/core/__tests__/ReactStateSetters-test.js
index ed57e77f01..9d5661175a 100644
--- a/src/core/__tests__/ReactStateSetters-test.js
+++ b/src/core/__tests__/ReactStateSetters-test.js
@@ -55,7 +55,7 @@ describe('ReactStateSetters', function() {
 
   it('createStateSetter should update state', function() {
     var instance = <TestComponent />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     expect(instance.state).toEqual({foo: 'foo'});
 
     var setter = ReactStateSetters.createStateSetter(
@@ -78,7 +78,7 @@ describe('ReactStateSetters', function() {
 
   it('createStateKeySetter should update state', function() {
     var instance = <TestComponent />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     expect(instance.state).toEqual({foo: 'foo'});
 
     var setter = ReactStateSetters.createStateKeySetter(instance, 'foo');
@@ -94,7 +94,7 @@ describe('ReactStateSetters', function() {
 
   it('createStateKeySetter is memoized', function() {
     var instance = <TestComponent />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     expect(instance.state).toEqual({foo: 'foo'});
 
     var foo1 = ReactStateSetters.createStateKeySetter(instance, 'foo');
@@ -109,7 +109,7 @@ describe('ReactStateSetters', function() {
 
   it('createStateSetter should update state from mixin', function() {
     var instance = <TestComponentWithMixin />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     expect(instance.state).toEqual({foo: 'foo'});
 
     var setter = instance.createStateSetter(
@@ -131,7 +131,7 @@ describe('ReactStateSetters', function() {
 
   it('createStateKeySetter should update state with mixin', function() {
     var instance = <TestComponentWithMixin />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     expect(instance.state).toEqual({foo: 'foo'});
 
     var setter = instance.createStateKeySetter('foo');
@@ -147,7 +147,7 @@ describe('ReactStateSetters', function() {
 
   it('createStateKeySetter is memoized with mixin', function() {
     var instance = <TestComponentWithMixin />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     expect(instance.state).toEqual({foo: 'foo'});
 
     var foo1 = instance.createStateKeySetter('foo');
diff --git a/src/core/__tests__/ReactUpdates-test.js b/src/core/__tests__/ReactUpdates-test.js
index 01accb6b93..690af3b443 100644
--- a/src/core/__tests__/ReactUpdates-test.js
+++ b/src/core/__tests__/ReactUpdates-test.js
@@ -318,7 +318,7 @@ describe('ReactUpdates', function() {
     expect(childRenderCount).toBe(0);
 
     var instance = <Parent />;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
 
     expect(parentRenderCount).toBe(1);
     expect(childRenderCount).toBe(1);
@@ -437,7 +437,7 @@ describe('ReactUpdates', function() {
     });
 
     var root = <App />;
-    ReactTestUtils.renderIntoDocument(root);
+    root = ReactTestUtils.renderIntoDocument(root);
 
     function expectUpdates(desiredWillUpdates, desiredDidUpdates) {
       expect(willUpdates).toEqual(desiredWillUpdates);
diff --git a/src/utils/__tests__/sliceChildren-test.js b/src/utils/__tests__/sliceChildren-test.js
index 5ccc826867..195bcd4e6e 100644
--- a/src/utils/__tests__/sliceChildren-test.js
+++ b/src/utils/__tests__/sliceChildren-test.js
@@ -53,7 +53,7 @@ describe('sliceChildren', function() {
 
   function renderAndSlice(set, start, end) {
     var instance = <Partial start={start} end={end}>{set}</Partial>;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     var rendered = reactComponentExpect(instance)
       .expectRenderedChild()
       .instance();
@@ -106,7 +106,7 @@ describe('sliceChildren', function() {
     var c = <div />;
 
     var instance = <Partial start={1} end={2}>{a}{b}{c}</Partial>;
-    ReactTestUtils.renderIntoDocument(instance);
+    instance = ReactTestUtils.renderIntoDocument(instance);
     var rendered = reactComponentExpect(instance)
       .expectRenderedChild()
       .instance();