diff --git a/test/src/index.ts b/test/src/index.ts
index 7bd75eeda..a8f924998 100644
--- a/test/src/index.ts
+++ b/test/src/index.ts
@@ -46,6 +46,7 @@ import './ui/tabbar.spec';
 import './ui/tabpanel.spec';
 import './ui/title.spec';
 import './ui/widget.spec';
+import './ui/vdom.spec';
 
 import '../../styles/base.css';
 import '../index.css';
diff --git a/test/src/ui/vdom.spec.ts b/test/src/ui/vdom.spec.ts
new file mode 100644
index 000000000..879bc2359
--- /dev/null
+++ b/test/src/ui/vdom.spec.ts
@@ -0,0 +1,378 @@
+/*-----------------------------------------------------------------------------
+| Copyright (c) 2014-2016, PhosphorJS Contributors
+|
+| Distributed under the terms of the BSD 3-Clause License.
+|
+| The full license is in the file LICENSE, distributed with this software.
+|----------------------------------------------------------------------------*/
+import expect = require('expect.js');
+
+import {
+  VNode, h, realize, render
+} from '../../../lib/ui/vdom';
+
+
+describe('ui/vdom', () => {
+
+  describe('VNode', () => {
+
+    describe('#constructor()', () => {
+
+      it('should create a text VNode', () => {
+        let vnode = new VNode('text', 'foo', {}, []);
+        expect(vnode).to.be.a(VNode);
+      });
+
+      it('should create an element VNode', () => {
+        let vnode = new VNode('element', 'img', {}, []);
+        expect(vnode).to.be.a(VNode);
+      });
+
+    });
+
+    describe('#type', () => {
+
+      it('should be the type of the node', () => {
+        let vnode = new VNode('text', 'foo', {}, []);
+        expect(vnode.type).to.be('text');
+        vnode = new VNode('element', 'img', {}, []);
+        expect(vnode.type).to.be('element');
+      });
+
+    });
+
+    describe('#tag', () => {
+
+      it('should be the text of a text type node', () => {
+        let vnode = new VNode('text', 'foo', {}, []);
+        expect(vnode.tag).to.be('foo');
+      });
+
+      it('should be the element tag name for an element type node', () => {
+        let vnode = new VNode('element', 'img', {}, []);
+        expect(vnode.tag).to.be('img');
+      });
+
+    });
+
+    describe('#attrs', () => {
+
+      it('should be the attrs given to the constructor', () => {
+        let attrs = { foo: 'bar' };
+        let vnode = new VNode('element', 'img', attrs, []);
+        expect(vnode.attrs).to.be(attrs);
+      });
+
+    });
+
+    describe('#children', () => {
+
+      it('should be the child elements given to the constructor', () => {
+        let children = [h.a(), h.img()];
+        let vnode = new VNode('element', 'div', {}, children);
+        expect(vnode.children).to.be(children);
+      });
+
+    });
+
+  });
+
+  describe('h()', () => {
+
+    it('should create a new virtual DOM node', () => {
+      let vnode = h('a');
+      expect(vnode).to.be.a(VNode);
+    });
+
+    it('should accept string literals for children and convert them to text nodes', () => {
+      let vnode = h('div', {}, ['foo', 'bar']);
+      expect(vnode.children[0]).to.be.a(VNode);
+      expect(vnode.children[0].type).to.be('text');
+      expect(vnode.children[0].tag).to.be('foo');
+      expect(vnode.children[1].type).to.be('text');
+      expect(vnode.children[1].tag).to.be('bar');
+    });
+
+    it('should accept other virtual DOM nodes for children', () => {
+      let children = [h('a'), h('img')];
+      let vnode = h('div', {}, children);
+      expect(vnode.children[0]).to.be(children[0]);
+      expect(vnode.children[0].type).to.be('element');
+      expect(vnode.children[0].tag).to.be('a');
+      expect(vnode.children[1].type).to.be('element');
+      expect(vnode.children[1].tag).to.be('img');
+    });
+
+    it('should accept a mix of string literals and virtual DOM nodes', () => {
+      let children = ['foo', h('img')];
+      let vnode = h('div', {}, children);
+      expect(vnode.children[1]).to.be(children[1]);
+      expect(vnode.children[0].type).to.be('text');
+      expect(vnode.children[0].tag).to.be('foo');
+      expect(vnode.children[1].type).to.be('element');
+      expect(vnode.children[1].tag).to.be('img');
+    });
+
+    it('should ignore `null` child values', () => {
+      let children = ['foo', null, h('img')];
+      let vnode = h('div', {}, children);
+      expect(vnode.children[1]).to.be(children[2]);
+      expect(vnode.children[0].type).to.be('text');
+      expect(vnode.children[0].tag).to.be('foo');
+      expect(vnode.children[1].type).to.be('element');
+      expect(vnode.children[1].tag).to.be('img');
+    });
+
+    it('should accept a string as the second argument', () => {
+      let vnode = h('div', 'foo');
+      expect(vnode.children[0].type).to.be('text');
+      expect(vnode.children[0].tag).to.be('foo');
+    });
+
+    it('should accept a virtual node as the second argument', () => {
+      let vnode = h('div', h('a'));
+      expect(vnode.children[0].type).to.be('element');
+      expect(vnode.children[0].tag).to.be('a');
+    });
+
+    it('should accept an array as the second argument', () => {
+      let children = [h('a'), h('img')];
+      let vnode = h('div', children);
+      expect(vnode.children[0]).to.be(children[0]);
+      expect(vnode.children[0].type).to.be('element');
+      expect(vnode.children[0].tag).to.be('a');
+      expect(vnode.children[1].type).to.be('element');
+      expect(vnode.children[1].tag).to.be('img');
+    });
+
+    it('should accept other nodes as variadic args', () => {
+      let vnode = h('div', h('a'), h('img'));
+      expect(vnode.children[0].type).to.be('element');
+      expect(vnode.children[0].tag).to.be('a');
+      expect(vnode.children[1].type).to.be('element');
+      expect(vnode.children[1].tag).to.be('img');
+    });
+
+    it('should set the attrs directly', () => {
+      let attrs = { alt: 'foo', style: { color: 'black' },
+                    dataset: { foo: 1 } };
+      let vnode = h('img', attrs);
+      expect(vnode.attrs).to.eql(attrs);
+    });
+
+  });
+
+  describe('h', () => {
+
+    it('should create the appropriate element tag', () => {
+      let vnode = h.a();
+      expect(vnode.tag).to.be('a');
+      expect(h.abbr().tag).to.be('abbr');
+      expect(h.address().tag).to.be('address');
+      expect(h.area().tag).to.be('area');
+      expect(h.article().tag).to.be('article');
+      expect(h.aside().tag).to.be('aside');
+      expect(h.audio().tag).to.be('audio');
+      expect(h.b().tag).to.be('b');
+      expect(h.bdi().tag).to.be('bdi');
+      expect(h.bdo().tag).to.be('bdo');
+      expect(h.blockquote().tag).to.be('blockquote');
+      expect(h.br().tag).to.be('br');
+      expect(h.button().tag).to.be('button');
+      expect(h.canvas().tag).to.be('canvas');
+      expect(h.caption().tag).to.be('caption');
+      expect(h.cite().tag).to.be('cite');
+      expect(h.code().tag).to.be('code');
+      expect(h.col().tag).to.be('col');
+      expect(h.colgroup().tag).to.be('colgroup');
+      expect(h.data().tag).to.be('data');
+      expect(h.datalist().tag).to.be('datalist');
+      expect(h.dd().tag).to.be('dd');
+      expect(h.del().tag).to.be('del');
+      expect(h.dfn().tag).to.be('dfn');
+      expect(h.div().tag).to.be('div');
+      expect(h.dl().tag).to.be('dl');
+      expect(h.dt().tag).to.be('dt');
+      expect(h.em().tag).to.be('em');
+      expect(h.embed().tag).to.be('embed');
+      expect(h.fieldset().tag).to.be('fieldset');
+      expect(h.figcaption().tag).to.be('figcaption');
+      expect(h.figure().tag).to.be('figure');
+      expect(h.footer().tag).to.be('footer');
+      expect(h.form().tag).to.be('form');
+      expect(h.h1().tag).to.be('h1');
+      expect(h.h2().tag).to.be('h2');
+      expect(h.h3().tag).to.be('h3');
+      expect(h.h4().tag).to.be('h4');
+      expect(h.h5().tag).to.be('h5');
+      expect(h.h6().tag).to.be('h6');
+      expect(h.header().tag).to.be('header');
+      expect(h.hr().tag).to.be('hr');
+      expect(h.i().tag).to.be('i');
+      expect(h.iframe().tag).to.be('iframe');
+      expect(h.img().tag).to.be('img');
+      expect(h.input().tag).to.be('input');
+      expect(h.ins().tag).to.be('ins');
+      expect(h.kbd().tag).to.be('kbd');
+      expect(h.label().tag).to.be('label');
+      expect(h.legend().tag).to.be('legend');
+      expect(h.li().tag).to.be('li');
+      expect(h.main().tag).to.be('main');
+      expect(h.map().tag).to.be('map');
+      expect(h.mark().tag).to.be('mark');
+      expect(h.meter().tag).to.be('meter');
+      expect(h.nav().tag).to.be('nav');
+      expect(h.noscript().tag).to.be('noscript');
+      expect(h.object().tag).to.be('object');
+      expect(h.ol().tag).to.be('ol');
+      expect(h.optgroup().tag).to.be('optgroup');
+      expect(h.option().tag).to.be('option');
+      expect(h.output().tag).to.be('output');
+      expect(h.p().tag).to.be('p');
+      expect(h.param().tag).to.be('param');
+      expect(h.pre().tag).to.be('pre');
+      expect(h.progress().tag).to.be('progress');
+      expect(h.q().tag).to.be('q');
+      expect(h.rp().tag).to.be('rp');
+      expect(h.rt().tag).to.be('rt');
+      expect(h.ruby().tag).to.be('ruby');
+      expect(h.s().tag).to.be('s');
+      expect(h.samp().tag).to.be('samp');
+      expect(h.section().tag).to.be('section');
+      expect(h.select().tag).to.be('select');
+      expect(h.small().tag).to.be('small');
+      expect(h.source().tag).to.be('source');
+      expect(h.span().tag).to.be('span');
+      expect(h.strong().tag).to.be('strong');
+      expect(h.sub().tag).to.be('sub');
+      expect(h.summary().tag).to.be('summary');
+      expect(h.sup().tag).to.be('sup');
+      expect(h.table().tag).to.be('table');
+      expect(h.tbody().tag).to.be('tbody');
+      expect(h.td().tag).to.be('td');
+      expect(h.textarea().tag).to.be('textarea');
+      expect(h.tfoot().tag).to.be('tfoot');
+      expect(h.th().tag).to.be('th');
+      expect(h.thead().tag).to.be('thead');
+      expect(h.time().tag).to.be('time');
+      expect(h.title().tag).to.be('title');
+      expect(h.tr().tag).to.be('tr');
+      expect(h.track().tag).to.be('track');
+      expect(h.u().tag).to.be('u');
+      expect(h.ul().tag).to.be('ul');
+      expect(h.var_().tag).to.be('var');
+      expect(h.video().tag).to.be('video');
+      expect(h.wbr().tag).to.be('wbr');
+    });
+
+  });
+
+  describe('realize()', () => {
+
+    it('should create a real DOM node from a virtual DOM node', () => {
+      let node = realize(h.div([h.a(), h.img()]));
+      expect(node.nodeName.toLowerCase()).to.be('div');
+      expect(node.firstChild.nodeName.toLowerCase()).to.be('a');
+      expect(node.lastChild.nodeName.toLowerCase()).to.be('img');
+    });
+
+  });
+
+  describe('render()', () => {
+
+    it('should render virtual DOM content into a host elememnt', () => {
+      let host = document.createElement('div');
+      render(h.img(), host);
+      expect(host.firstChild.nodeName.toLowerCase()).to.be('img');
+    });
+
+    it('should render the delta from the previous rendering', () => {
+      let host = document.createElement('div');
+      let children = [h.a(), h.span(), h.img()];
+      render(children, host);
+
+      let first = host.firstChild;
+      let last = host.lastChild;
+      expect(first.nodeName.toLowerCase()).to.be('a');
+      expect(last.nodeName.toLowerCase()).to.be('img');
+      children = [children[0], new VNode('text', 'foo', {}, []), children[1]];
+      render(children, host);
+      expect(host.firstChild).to.be(first);
+      expect(host.lastChild).to.not.be(last);
+      expect(host.lastChild.nodeName.toLowerCase()).to.be('span');
+    });
+
+    it('should clear the rendering if `null` content is provided', () => {
+      let host = document.createElement('div');
+      render(h('div', ['bar', 'foo']), host);
+      let div = host.firstChild as HTMLElement;
+      expect(div.childNodes.length).to.be(2);
+      render(null, host);
+      expect(host.children.length).to.be(0);
+    });
+
+    it('should update attributes', () => {
+      let host = document.createElement('div');
+      let img = h.img({ alt: 'foo', height: 100, style: { color: 'white' },
+                        dataset: { foo: 2, bar: 2 },
+                        onload: () => { /* no-op */ },
+                        srcset: 'foo' });
+      let children = [h.a(), img];
+      render(h('div', children), host);
+      children[1] = h.img({ alt: 'bar', width: 100, style: { border: '1px' },
+                            dataset: { bar: 1, baz: 3 }, sizes: 'baz' });
+      render(h('div', children), host);
+      expect((host.firstChild.lastChild as HTMLImageElement).alt).to.be('bar');
+    });
+
+    it('should not recreate a DOM node that moves if it has a key id', () => {
+      let host = document.createElement('div');
+      let children = [h.span({ key: '1' }), h.span({ key: '2' }),
+                      h.span({ key: '3' }), h.span({ key: '4' })];
+      render(children, host);
+      let child = host.children[1];
+      let newChildren = [children[0], children[2], children[1], children[3]];
+      render(newChildren, host);
+      let newChild = (host as HTMLElement).children[2];
+      expect(child).to.be(newChild);
+    });
+
+    it('should still recreate the DOM node if the node type changes', () => {
+      let host = document.createElement('div');
+      let children = [h.span({ key: '1' }), h.span({ key: '2' }),
+                      h.span({ key: '3' }), h.span({ key: '4' })];
+      render(children, host);
+      let child = host.children[1];
+      let newChildren = [children[0], children[2], h.div({ key: '2' }),
+                         children[3]];
+      render(newChildren, host);
+      let newChild = host.children[2];
+      expect(child).to.not.be(newChild);
+    });
+
+    it('should handle a new keyed item', () => {
+      let host = document.createElement('div');
+      let children = [h.span({ key: '1' }), h.span({ key: '2' }),
+                      h.span({ key: '3' }), h.span({ key: '4' })];
+      render(children, host);
+      let newChildren = children.slice();
+      newChildren[3] = h.div({ key: '5' });
+      render(newChildren, host);
+      let newChild = host.lastChild;
+      expect(newChild.nodeName.toLowerCase()).to.be('div');
+    });
+
+    it('should update the text of a text node', () => {
+      let host = document.createElement('div');
+      render(new VNode('text', 'foo', {}, []), host);
+      let div = host.childNodes[0] as HTMLElement;
+      expect(div.textContent).to.be('foo');
+      render(new VNode('text', 'bar', {}, []), host);
+      let newDiv = host.childNodes[0] as HTMLElement;
+      expect(newDiv).to.be(div);
+      expect(div.textContent).to.be('bar');
+    });
+
+  });
+
+});