diff --git a/src/isomorphic/ReactDebugTool.js b/src/isomorphic/ReactDebugTool.js
index 4d2c2a3536..ea89a93641 100644
--- a/src/isomorphic/ReactDebugTool.js
+++ b/src/isomorphic/ReactDebugTool.js
@@ -70,6 +70,9 @@ var ReactDebugTool = {
   onUnmountComponent(internalInstance) {
     emitEvent('onUnmountComponent', internalInstance);
   },
+  onTestEvent() {
+    emitEvent('onTestEvent');
+  },
 };
 
 ReactDebugTool.addDevtool(ReactInvalidSetStateWarningDevTool);
diff --git a/src/isomorphic/__tests__/ReactDebugTool-test.js b/src/isomorphic/__tests__/ReactDebugTool-test.js
new file mode 100644
index 0000000000..bae09516f5
--- /dev/null
+++ b/src/isomorphic/__tests__/ReactDebugTool-test.js
@@ -0,0 +1,75 @@
+/**
+ * Copyright 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @emails react-core
+ */
+
+'use strict';
+
+describe('ReactDebugTool', function() {
+  var ReactDebugTool;
+
+  beforeEach(function() {
+    jest.resetModuleRegistry();
+    ReactDebugTool = require('ReactDebugTool');
+  });
+
+  it('should add and remove devtools', () => {
+    var handler1 = jasmine.createSpy('spy');
+    var handler2 = jasmine.createSpy('spy');
+    var devtool1 = {onTestEvent: handler1};
+    var devtool2 = {onTestEvent: handler2};
+
+    ReactDebugTool.addDevtool(devtool1);
+    ReactDebugTool.onTestEvent();
+    expect(handler1.calls.length).toBe(1);
+    expect(handler2.calls.length).toBe(0);
+
+    ReactDebugTool.onTestEvent();
+    expect(handler1.calls.length).toBe(2);
+    expect(handler2.calls.length).toBe(0);
+
+    ReactDebugTool.addDevtool(devtool2);
+    ReactDebugTool.onTestEvent();
+    expect(handler1.calls.length).toBe(3);
+    expect(handler2.calls.length).toBe(1);
+
+    ReactDebugTool.onTestEvent();
+    expect(handler1.calls.length).toBe(4);
+    expect(handler2.calls.length).toBe(2);
+
+    ReactDebugTool.removeDevtool(devtool1);
+    ReactDebugTool.onTestEvent();
+    expect(handler1.calls.length).toBe(4);
+    expect(handler2.calls.length).toBe(3);
+
+    ReactDebugTool.removeDevtool(devtool2);
+    ReactDebugTool.onTestEvent();
+    expect(handler1.calls.length).toBe(4);
+    expect(handler2.calls.length).toBe(3);
+  });
+
+  it('warns once when an error is thrown in devtool', () => {
+    spyOn(console, 'error');
+    ReactDebugTool.addDevtool({
+      onTestEvent() {
+        throw new Error('Hi.');
+      },
+    });
+
+    ReactDebugTool.onTestEvent();
+    expect(console.error.calls.length).toBe(1);
+    expect(console.error.argsForCall[0][0]).toContain(
+      'exception thrown by devtool while handling ' +
+      'onTestEvent: Hi.'
+    );
+
+    ReactDebugTool.onTestEvent();
+    expect(console.error.calls.length).toBe(1);
+  });
+});
diff --git a/src/renderers/dom/shared/ReactDOMDebugTool.js b/src/renderers/dom/shared/ReactDOMDebugTool.js
index 9fcc3763fa..b90c122450 100644
--- a/src/renderers/dom/shared/ReactDOMDebugTool.js
+++ b/src/renderers/dom/shared/ReactDOMDebugTool.js
@@ -59,6 +59,9 @@ var ReactDOMDebugTool = {
   onDeleteValueForProperty(node, name) {
     emitEvent('onDeleteValueForProperty', node, name);
   },
+  onTestEvent() {
+    emitEvent('onTestEvent');
+  },
 };
 
 ReactDOMDebugTool.addDevtool(ReactDOMUnknownPropertyDevtool);
diff --git a/src/renderers/dom/shared/__tests__/ReactDOMDebugTool-test.js b/src/renderers/dom/shared/__tests__/ReactDOMDebugTool-test.js
new file mode 100644
index 0000000000..b4a94ec837
--- /dev/null
+++ b/src/renderers/dom/shared/__tests__/ReactDOMDebugTool-test.js
@@ -0,0 +1,75 @@
+/**
+ * Copyright 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @emails react-core
+ */
+
+'use strict';
+
+describe('ReactDOMDebugTool', function() {
+  var ReactDOMDebugTool;
+
+  beforeEach(function() {
+    jest.resetModuleRegistry();
+    ReactDOMDebugTool = require('ReactDOMDebugTool');
+  });
+
+  it('should add and remove devtools', () => {
+    var handler1 = jasmine.createSpy('spy');
+    var handler2 = jasmine.createSpy('spy');
+    var devtool1 = {onTestEvent: handler1};
+    var devtool2 = {onTestEvent: handler2};
+
+    ReactDOMDebugTool.addDevtool(devtool1);
+    ReactDOMDebugTool.onTestEvent();
+    expect(handler1.calls.length).toBe(1);
+    expect(handler2.calls.length).toBe(0);
+
+    ReactDOMDebugTool.onTestEvent();
+    expect(handler1.calls.length).toBe(2);
+    expect(handler2.calls.length).toBe(0);
+
+    ReactDOMDebugTool.addDevtool(devtool2);
+    ReactDOMDebugTool.onTestEvent();
+    expect(handler1.calls.length).toBe(3);
+    expect(handler2.calls.length).toBe(1);
+
+    ReactDOMDebugTool.onTestEvent();
+    expect(handler1.calls.length).toBe(4);
+    expect(handler2.calls.length).toBe(2);
+
+    ReactDOMDebugTool.removeDevtool(devtool1);
+    ReactDOMDebugTool.onTestEvent();
+    expect(handler1.calls.length).toBe(4);
+    expect(handler2.calls.length).toBe(3);
+
+    ReactDOMDebugTool.removeDevtool(devtool2);
+    ReactDOMDebugTool.onTestEvent();
+    expect(handler1.calls.length).toBe(4);
+    expect(handler2.calls.length).toBe(3);
+  });
+
+  it('warns once when an error is thrown in devtool', () => {
+    spyOn(console, 'error');
+    ReactDOMDebugTool.addDevtool({
+      onTestEvent() {
+        throw new Error('Hi.');
+      },
+    });
+
+    ReactDOMDebugTool.onTestEvent();
+    expect(console.error.calls.length).toBe(1);
+    expect(console.error.argsForCall[0][0]).toContain(
+      'exception thrown by devtool while handling ' +
+      'onTestEvent: Hi.'
+    );
+
+    ReactDOMDebugTool.onTestEvent();
+    expect(console.error.calls.length).toBe(1);
+  });
+});