diff --git a/package.json b/package.json
index 4a4bbc7..eb0de28 100644
--- a/package.json
+++ b/package.json
@@ -19,8 +19,10 @@
     "fbjs": "^0.8.0"
   },
   "devDependencies": {
+    "chai": "^3.5.0",
     "mocha": "^2.3.3",
-    "react": "^15.0.0 || ^0.14.0"
+    "react": "^15.0.0 || ^0.14.0",
+    "sinon": "^1.17.6"
   },
   "scripts": {
     "test": "mocha"
diff --git a/test.js b/test.js
index 9dfb2e7..0670085 100644
--- a/test.js
+++ b/test.js
@@ -4,62 +4,97 @@
  */
 'use strict';
 
-var assert = require('assert');
+var expect = require('chai').expect;
+var sinon = require('sinon');
+var warning = require('fbjs/lib/warning');
 var decorate = require('./index');
 
+
+
 /**
  *
  */
 describe('pure-render-decorator', function() {
-  function Component() {};
-  decorate(Component);
 
-  var component = new Component();
-  component.props = { foo: 1 };
-  component.state = { bar: 2 };
+  /**
+   *
+   */
+  beforeEach(function() {
+    function Component() {};
+    decorate(Component);
 
-  it('should add a method named shouldComponentUpdate', function() {
-    assert.ok('shouldComponentUpdate' in component);
-    assert.ok(typeof component.shouldComponentUpdate === 'function');
+    this.component = new Component();
+    this.component.props = { foo: 1 };
+    this.component.state = { bar: 2 };
   });
 
-  it('should throw an error if shouldComponentUpdate is already implemented', function() {
-    function ComponentWithShouldComponentUpdate() {};
-    ComponentWithShouldComponentUpdate.prototype.shouldComponentUpdate = () => false;
+  /**
+   *
+   */
+  it('should warn if shouldComponentUpdate is already implemented', function() {
+    function Component() {};
+    Component.prototype.shouldComponentUpdate = () => true;
+
+    var sandbox = sinon.sandbox.create();
+    var mock = sandbox.mock(console);
+
+    mock
+      .expects('error')
+      .once()
+      .withArgs(
+        'Warning: Cannot decorate `Component` with @pureRenderDecorator, '
+        + 'because it already implements `shouldComponentUpdate().'
+      );
+
+    decorate(Component);
 
-    var expectedErrorMessage = "Cannot add a pure render decorator to "
-      + "ComponentWithShouldComponentUpdate, because it already implements "
-      + "`shouldComponentUpdate\\(\\)`";
-    assert.throws(() => decorate(ComponentWithShouldComponentUpdate), new RegExp(expectedErrorMessage));
+    mock.verify();
+    sandbox.restore();
   });
 
-  it('should return true if the props and state are different', function() {
-    assert.ok(component.shouldComponentUpdate({}, {}));
+  /**
+   *
+   */
+  it('should add a method named shouldComponentUpdate', function() {
+    expect(this.component).to.respondTo('shouldComponentUpdate');
   });
 
-  it('should return false if the props and state are reference-equals', function() {
-    assert.ok(
-      !component.shouldComponentUpdate(
-        component.props,
-        component.state
-      )
-    );
+  /**
+   *
+   */
+  it('should return the component', function() {
+    function Component() {};
+    expect(decorate(Component)).to.equal(Component);
   });
 
-  it('should return false if props and state are shallow-equals but different references', function() {
-    assert.ok(
-      !component.shouldComponentUpdate(
-        { foo: 1 },
-        { bar: 2 }
+  /**
+   *
+   */
+  it('should update if the props and state are different', function() {
+    expect(this.component.shouldComponentUpdate({}, {})).to.be.true;
+  });
+
+  /**
+   *
+   */
+  it('should not update if the props and state are reference-equals', function() {
+    expect(
+      this.component.shouldComponentUpdate(
+        this.component.props,
+        this.component.state
       )
-    );
+    ).to.be.false;
   });
 
   /**
    *
    */
-  it('should return the component', function() {
-    var c = function() {};
-    assert.equal(c, decorate(c));
+  it('should not update if props and state are shallow-equals but different references', function() {
+    expect(
+      this.component.shouldComponentUpdate(
+        { foo: 1 },
+        { bar: 2 }
+      )
+    ).to.be.false;
   });
 });