diff --git a/chai-subset/chai-subset.d.ts b/chai-subset/chai-subset.d.ts
index 44bbef9cc1..b9605241b7 100644
--- a/chai-subset/chai-subset.d.ts
+++ b/chai-subset/chai-subset.d.ts
@@ -1,6 +1,6 @@
 // Type definitions for chai-subset 1.0.0
 // Project: https://github.com/e-conomic/chai-subset
-// Definitions by: Sam Noedel <https://github.com/delta62/>
+// Definitions by: Sam Noedel <https://github.com/delta62/>, Andrew Brown <https://github.com/AGBrown>
 // Definitions: https://github.com/borisyankov/DefinitelyTyped
 
 /// <reference path="../chai/chai.d.ts" />
@@ -11,10 +11,6 @@ declare module Chai {
     }
 }
 
-interface Object {
-    should: Chai.Assertion;
-}
-
 declare module "chai-subset" {
     function chaiSubset(chai: any, utils: any): void;
     export = chaiSubset;
diff --git a/chai/chai-tests.ts b/chai/chai-tests.ts
index c3f6fe06af..fdd23da164 100644
--- a/chai/chai-tests.ts
+++ b/chai/chai-tests.ts
@@ -5,290 +5,416 @@ import chai = require('chai');
 
 var expect = chai.expect;
 var assert = chai.assert;
+var should = chai.should();
 declare var err: Function;
 
 function chaiVersion() {
     expect(chai).to.have.property('version');
+    (<Object><{}>chai).should.have.property('version');
 }
 
 function assertion() {
     expect('test').to.be.a('string');
+    'test'.should.be.a('string');
     expect('foo').to.equal('foo');
+    'foo'.should.equal('foo');
+    should.equal('foo', 'foo');
+}
+
+function fail() {
+    err(() => {
+        should.fail('foo', 'bar');
+    }, 'expected fail to throw an AssertionError');
+    err(() => {
+        should.fail('foo', 'bar', 'should fail');
+    }, 'expected fail to throw an AssertionError');
+    err(() => {
+        should.fail('foo', 'bar', 'should fail', 'equal');
+    }, 'expected fail to throw an AssertionError');
 }
 
 // ReSharper disable once InconsistentNaming
 function _true() {
     expect(true).to.be.true;
+    true.should.be.true;
     expect(false).to.not.be.true;
+    false.should.not.be.true;
     expect(1).to.not.be.true;
+    (1).should.not.be.true;
 
     err(() => {
         expect('test').to.be.true;
+        'test'.should.be.true;
     }, 'expected \'test\' to be true');
 }
 
 function ok() {
     expect(true).to.be.ok;
+    true.should.be.ok;
     expect(false).to.not.be.ok;
+    false.should.not.be.ok;
     expect(1).to.be.ok;
+    (1).should.be.ok;
     expect(0).to.not.be.ok;
+    (0).should.not.be.ok;
 
     err(() => {
         expect('').to.be.ok;
+        ''.should.be.ok;
     }, 'expected \'\' to be truthy');
 
     err(() => {
         expect('test').to.not.be.ok;
+        'test'.should.not.be.ok;
     }, 'expected \'test\' to be falsy');
 }
 
 function _false() {
     expect(false).to.be.false;
+    false.should.be.false;
     expect(true).to.not.be.false;
+    true.should.not.be.false;
     expect(0).to.not.be.false;
+    (0).should.not.be.false;
 
     err(() => {
         expect('').to.be.false;
+        ''.should.be.false;
     }, 'expected \'\' to be false');
 }
 
 function _null() {
     expect(null).to.be.null;
+    should.equal(null, null);
     expect(false).to.not.be.null;
+    false.should.not.be.null;
 
     err(() => {
         expect('').to.be.null;
+        ''.should.be.null;
     }, 'expected \'\' to be null');
 }
 
 function _undefined() {
     expect(undefined).to.be.undefined;
+    should.equal(undefined, undefined);
     expect(null).to.not.be.undefined;
+    should.not.equal(null, undefined);
 
     err(() => {
         expect('').to.be.undefined;
+        ''.should.be.undefined;
     }, 'expected \'\' to be undefined');
 }
 
 function exist() {
     var foo = 'bar';
     expect(foo).to.exist;
+    should.exist(foo);
     expect(void(0)).to.not.exist;
+    should.not.exist(void (0));
 }
 
 function arguments() {
     var args = arguments;
     expect(args).to.be.arguments;
+    args.should.be.arguments;
     expect([]).to.not.be.arguments;
+    [].should.not.be.arguments;
     expect(args).to.be.an('arguments').and.be.arguments;
+    args.should.be.an('arguments').and.be.arguments;
     expect([]).to.be.an('array').and.not.be.Arguments;
+    [].should.be.an('array').and.not.be.Arguments;
 }
 
 function equal() {
     expect(undefined).to.equal(void(0));
+    should.equal(undefined, void(0));
 }
 
 function _typeof() {
     expect('test').to.be.a('string');
+    'test'.should.be.a('string');
 
     err(() => {
         expect('test').to.not.be.a('string');
+        'test'.should.not.be.a('string');
     }, 'expected \'test\' not to be a string');
 
     expect(arguments).to.be.an('arguments');
+    arguments.should.be.an('arguments');
 
     expect(5).to.be.a('number');
+    (5).should.be.a('number');
+
     expect(new Number(1)).to.be.a('number');
+    (new Number(1)).should.be.a('number');
     expect(Number(1)).to.be.a('number');
+    Number(1).should.be.a('number');
     expect(true).to.be.a('boolean');
+    true.should.be.a('boolean');
     expect(new Array()).to.be.a('array');
+    (new Array()).should.be.a('array');
     expect(new Object()).to.be.a('object');
+    (new Object()).should.be.a('object');
     expect({}).to.be.a('object');
+    ({}).should.be.a('object');
     expect([]).to.be.a('array');
+    [].should.be.a('array');
     expect(() => { }).to.be.a('function');
+    (() => { }).should.be.a('function');
     expect(null).to.be.a('null');
+    // N.B. previous line has no should equivalent
 
     err(() => {
         expect(5).to.not.be.a('number', 'blah');
+        (5).should.not.be.a('number', 'blah');
     }, 'blah: expected 5 not to be a number');
 }
 
 class Foo { }
 function _instanceof() {
     expect(new Foo()).to.be.an.instanceof(Foo);
+    (new Foo()).should.be.an.instanceof(Foo);
 
     err(() => {
         expect(3).to.an.instanceof(Foo, 'blah');
+        (3).should.an.instanceof(Foo, 'blah');
     }, 'blah: expected 3 to be an instance of Foo');
 }
 
 function within() {
     expect(5).to.be.within(5, 10);
+    (5).should.be.within(5, 10);
     expect(5).to.be.within(3, 6);
+    (5).should.be.within(3, 6);
     expect(5).to.be.within(3, 5);
+    (5).should.be.within(3, 5);
     expect(5).to.not.be.within(1, 3);
+    (5).should.not.be.within(1, 3);
     expect('foo').to.have.length.within(2, 4);
+    'foo'.should.have.length.within(2, 4);
     expect([1, 2, 3]).to.have.length.within(2, 4);
+    [1, 2, 3].should.have.length.within(2, 4);
 
     err(() => {
         expect(5).to.not.be.within(4, 6, 'blah');
+        (5).should.not.be.within(4, 6, 'blah');
     }, 'blah: expected 5 to not be within 4..6', 'blah');
 
     err(() => {
         expect(10).to.be.within(50, 100, 'blah');
+        (10).should.be.within(50, 100, 'blah');
     }, 'blah: expected 10 to be within 50..100');
 
     err(() => {
         expect('foo').to.have.length.within(5, 7, 'blah');
+        'foo'.should.have.length.within(5, 7, 'blah');
     }, 'blah: expected \'foo\' to have a length within 5..7');
 
     err(() => {
         expect([1, 2, 3]).to.have.length.within(5, 7, 'blah');
+        [1, 2, 3].should.have.length.within(5, 7, 'blah');
     }, 'blah: expected [ 1, 2, 3 ] to have a length within 5..7');
 }
 
 function above() {
     expect(5).to.be.above(2);
+    (5).should.be.above(2);
     expect(5).to.be.greaterThan(2);
+    (5).should.be.greaterThan(2);
     expect(5).to.not.be.above(5);
+    (5).should.not.be.above(5);
     expect(5).to.not.be.above(6);
+    (5).should.not.be.above(6);
     expect('foo').to.have.length.above(2);
+    'foo'.should.have.length.above(2);
     expect([1, 2, 3]).to.have.length.above(2);
+    [1, 2, 3].should.have.length.above(2);
 
     err(() => {
         expect(5).to.be.above(6, 'blah');
+        (5).should.be.above(6, 'blah');
     }, 'blah: expected 5 to be above 6', 'blah');
 
     err(() => {
         expect(10).to.not.be.above(6, 'blah');
+        (10).should.not.be.above(6, 'blah');
     }, 'blah: expected 10 to be at most 6');
 
     err(() => {
         expect('foo').to.have.length.above(4, 'blah');
+        'foo'.should.have.length.above(4, 'blah');
     }, 'blah: expected \'foo\' to have a length above 4 but got 3');
 
     err(() => {
         expect([1, 2, 3]).to.have.length.above(4, 'blah');
+        [1, 2, 3].should.have.length.above(4, 'blah');
     }, 'blah: expected [ 1, 2, 3 ] to have a length above 4 but got 3');
 }
 
 function least() {
     expect(5).to.be.at.least(2);
+    (5).should.be.at.least(2);
     expect(5).to.be.at.least(5);
+    (5).should.be.at.least(5);
     expect(5).to.not.be.at.least(6);
+    (5).should.not.be.at.least(6);
     expect('foo').to.have.length.of.at.least(2);
+    'foo'.should.have.length.of.at.least(2);
     expect([1, 2, 3]).to.have.length.of.at.least(2);
+    [1, 2, 3].should.have.length.of.at.least(2);
 
     err(() => {
         expect(5).to.be.at.least(6, 'blah');
+        (5).should.be.at.least(6, 'blah');
     }, 'blah: expected 5 to be at least 6', 'blah');
 
     err(() => {
         expect(10).to.not.be.at.least(6, 'blah');
+        (10).should.not.be.at.least(6, 'blah');
     }, 'blah: expected 10 to be below 6');
 
     err(() => {
         expect('foo').to.have.length.of.at.least(4, 'blah');
+        'foo'.should.have.length.of.at.least(4, 'blah');
     }, 'blah: expected \'foo\' to have a length at least 4 but got 3');
 
     err(() => {
         expect([1, 2, 3]).to.have.length.of.at.least(4, 'blah');
+        [1, 2, 3].should.have.length.of.at.least(4, 'blah');
     }, 'blah: expected [ 1, 2, 3 ] to have a length at least 4 but got 3');
 
     err(() => {
         expect([1, 2, 3, 4]).to.not.have.length.of.at.least(4, 'blah');
+        [1, 2, 3, 4].should.not.have.length.of.at.least(4, 'blah');
     }, 'blah: expected [ 1, 2, 3, 4 ] to have a length below 4');
 }
 
 function below() {
     expect(2).to.be.below(5);
+    (2).should.be.below(5);
     expect(2).to.be.lessThan(5);
+    (2).should.be.lessThan(5);
     expect(2).to.not.be.below(2);
+    (2).should.not.be.below(2);
     expect(2).to.not.be.below(1);
+    (2).should.not.be.below(1);
     expect('foo').to.have.length.below(4);
+    'foo'.should.have.length.below(4);
     expect([1, 2, 3]).to.have.length.below(4);
+    [1, 2, 3].should.have.length.below(4);
 
     err(() => {
         expect(6).to.be.below(5, 'blah');
+        (6).should.be.below(5, 'blah');
     }, 'blah: expected 6 to be below 5');
 
     err(() => {
         expect(6).to.not.be.below(10, 'blah');
+        (6).should.not.be.below(10, 'blah');
     }, 'blah: expected 6 to be at least 10');
 
     err(() => {
         expect('foo').to.have.length.below(2, 'blah');
+        'foo'.should.have.length.below(2, 'blah');
     }, 'blah: expected \'foo\' to have a length below 2 but got 3');
 
     err(() => {
         expect([1, 2, 3]).to.have.length.below(2, 'blah');
+        [1, 2, 3].should.have.length.below(2, 'blah');
     }, 'blah: expected [ 1, 2, 3 ] to have a length below 2 but got 3');
 }
 
 function most() {
     expect(2).to.be.at.most(5);
+    (2).should.be.at.most(5);
     expect(2).to.be.at.most(2);
+    (2).should.be.at.most(2);
     expect(2).to.not.be.at.most(1);
+    (2).should.not.be.at.most(1);
     expect(2).to.not.be.at.most(1);
+    (2).should.not.be.at.most(1);
     expect('foo').to.have.length.of.at.most(4);
+    'foo'.should.have.length.of.at.most(4);
     expect([1, 2, 3]).to.have.length.of.at.most(4);
+    [1, 2, 3].should.have.length.of.at.most(4);
 
     err(() => {
         expect(6).to.be.at.most(5, 'blah');
+        (6).should.be.at.most(5, 'blah');
     }, 'blah: expected 6 to be at most 5');
 
     err(() => {
         expect(6).to.not.be.at.most(10, 'blah');
+        (6).should.not.be.at.most(10, 'blah');
     }, 'blah: expected 6 to be above 10');
 
     err(() => {
         expect('foo').to.have.length.of.at.most(2, 'blah');
+        'foo'.should.have.length.of.at.most(2, 'blah');
     }, 'blah: expected \'foo\' to have a length at most 2 but got 3');
 
     err(() => {
         expect([1, 2, 3]).to.have.length.of.at.most(2, 'blah');
+        [1, 2, 3].should.have.length.of.at.most(2, 'blah');
     }, 'blah: expected [ 1, 2, 3 ] to have a length at most 2 but got 3');
 
     err(() => {
         expect([1, 2]).to.not.have.length.of.at.most(2, 'blah');
+        [1, 2].should.not.have.length.of.at.most(2, 'blah');
     }, 'blah: expected [ 1, 2 ] to have a length above 2');
 }
 
 function match() {
     expect('foobar').to.match(/^foo/);
+    'foobar'.should.match(/^foo/);
     expect('foobar').to.not.match(/^bar/);
+    'foobar'.should.not.match(/^bar/);
 
     err(() => {
         expect('foobar').to.match(/^bar/i, 'blah');
+        'foobar'.should.match(/^bar/i, 'blah');
     }, 'blah: expected \'foobar\' to match /^bar/i');
 
     err(() => {
         expect('foobar').to.not.match(/^foo/i, 'blah');
+        'foobar'.should.not.match(/^foo/i, 'blah');
     }, 'blah: expected \'foobar\' not to match /^foo/i');
 }
 
 function length2() {
     expect('test').to.have.length(4);
+    'test'.should.have.length(4);
     expect('test').to.not.have.length(3);
+    'test'.should.not.have.length(3);
     expect([1, 2, 3]).to.have.length(3);
+    [1, 2, 3].should.have.length(3);
 
     err(() => {
         expect(4).to.have.length(3, 'blah');
+        (4).should.have.length(3, 'blah');
     }, 'blah: expected 4 to have a property \'length\'');
 
     err(() => {
         expect('asd').to.not.have.length(3, 'blah');
+        'asd'.should.not.have.length(3, 'blah');
     }, 'blah: expected \'asd\' to not have a length of 3');
 }
 
 function eql() {
     expect('test').to.eql('test');
+    'test'.should.eql('test');
     expect({ foo: 'bar' }).to.eql({ foo: 'bar' });
+    ({ foo: 'bar' }).should.eql({ foo: 'bar' });
     expect(1).to.eql(1);
+    (1).should.eql(1);
     expect('4').to.not.eql(4);
+    '4'.should.not.eql(4);
 
     err(() => {
         expect(4).to.eql(3, 'blah');
+        (4).should.eql(3, 'blah');
     }, 'blah: expected 4 to deeply equal 3');
 }
 
@@ -298,39 +424,54 @@ class Buffer {
 }
 function buffer() {
     expect(new Buffer([1])).to.eql(new Buffer([1]));
+    (new Buffer([1])).should.eql(new Buffer([1]));
 
     err(() => {
         expect(new Buffer([0])).to.eql(new Buffer([1]));
+        (new Buffer([0])).should.eql(new Buffer([1]));
     }, 'expected <Buffer 00> to deeply equal <Buffer 01>');
 }
 
 function equal2() {
     expect('test').to.equal('test');
+    'test'.should.equal('test');
+    should.equal('test', 'test');
     expect(1).to.equal(1);
+    (1).should.equal(1);
+    should.equal(1, 1);
 
     err(() => {
         expect(4).to.equal(3, 'blah');
+        (4).should.equal(3, 'blah');
+        should.equal(4, 3, 'blah');
     }, 'blah: expected 4 to equal 3');
 
     err(() => {
         expect('4').to.equal(4, 'blah');
+        '4'.should.equal(4, 'blah');
+        should.equal(4, 4, 'blah');
     }, 'blah: expected \'4\' to equal 4');
 }
 
 function deepEqual() {
     expect({ foo: 'bar' }).to.deep.equal({ foo: 'bar' });
+    ({ foo: 'bar' }).should.deep.equal({ foo: 'bar' });
     expect({ foo: 'bar' }).not.to.deep.equal({ foo: 'baz' });
 }
 
 function deepEqual2() {
     expect(/a/).to.deep.equal(/a/);
+    /a/.should.deep.equal(/a/);
     expect(/a/).not.to.deep.equal(/b/);
     expect(/a/).not.to.deep.equal({});
     expect(/a/g).to.deep.equal(/a/g);
+    /a/g.should.deep.equal(/a/g);
     expect(/a/g).not.to.deep.equal(/b/g);
     expect(/a/i).to.deep.equal(/a/i);
+    /a/i.should.deep.equal(/a/i);
     expect(/a/i).not.to.deep.equal(/b/i);
     expect(/a/m).to.deep.equal(/a/m);
+    /a/m.should.deep.equal(/a/m);
     expect(/a/m).not.to.deep.equal(/b/m);
 }
 
@@ -339,13 +480,18 @@ function deepEqual3() {
     var a = new Date(1, 2, 3);
     var b = new Date(4, 5, 6);
     expect(a).to.deep.equal(a);
+    a.should.deep.equal(a);
     expect(a).not.to.deep.equal(b);
+    a.should.not.deep.equal(b);
     expect(a).not.to.deep.equal({});
+    a.should.not.deep.equal({});
 }
 
 function deepInclude() {
     expect(['foo', 'bar']).to.deep.include(['bar', 'foo']);
+    ['foo', 'bar'].should.deep.include(['bar', 'foo']);
     expect(['foo', 'bar']).not.to.deep.equal(['foo', 'baz' ]);
+    ['foo', 'bar'].should.not.deep.equal(['foo', 'baz' ]);
 }
 
 class FakeArgs {
@@ -356,239 +502,332 @@ function empty() {
     FakeArgs.prototype.length = 0;
 
     expect('').to.be.empty;
+
+    ''.should.be.empty;
     expect('foo').not.to.be.empty;
+    'foo'.should.not.be.empty;
     expect([]).to.be.empty;
+    [].should.be.empty;
     expect(['foo']).not.to.be.empty;
+    ['foo'].should.not.be.empty;
     expect(new FakeArgs).to.be.empty;
+    (new FakeArgs).should.be.empty;
     expect({ arguments: 0 }).not.to.be.empty;
+    ({ arguments: 0 }).should.not.be.empty;
     expect({}).to.be.empty;
+    ({}).should.be.empty;
     expect({ foo: 'bar' }).not.to.be.empty;
+    ({ foo: 'bar' }).should.not.be.empty;
 
     err(() => {
         expect('').not.to.be.empty;
+        ''.should.not.be.empty;
     }, 'expected \'\' not to be empty');
 
     err(() => {
         expect('foo').to.be.empty;
+        'foo'.should.be.empty;
+        'foo'.should.be.empty;
     }, 'expected \'foo\' to be empty');
 
     err(() => {
         expect([]).not.to.be.empty;
+        [].should.not.be.empty;
     }, 'expected [] not to be empty');
 
     err(() => {
         expect(['foo']).to.be.empty;
+        ['foo'].should.be.empty;
     }, 'expected [ \'foo\' ] to be empty');
 
     err(() => {
         expect(new FakeArgs).not.to.be.empty;
+        (new FakeArgs).should.not.be.empty;
     }, 'expected { length: 0 } not to be empty');
 
     err(() => {
         expect({ arguments: 0 }).to.be.empty;
+        ({ arguments: 0 }).should.be.empty;
     }, 'expected { arguments: 0 } to be empty');
 
     err(() => {
         expect({}).not.to.be.empty;
+        ({}).should.not.be.empty;
     }, 'expected {} not to be empty');
 
     err(() => {
         expect({ foo: 'bar' }).to.be.empty;
+        ({ foo: 'bar' }).should.be.empty;
     }, 'expected { foo: \'bar\' } to be empty');
 }
 
 function property() {
     expect('test').to.have.property('length');
+    'test'.should.have.property('length');
     expect(4).to.not.have.property('length');
+    (4).should.not.have.property('length');
 
     expect({ 'foo.bar': 'baz' })
         .to.have.property('foo.bar');
+    ({ 'foo.bar': 'baz' }).should.have.property('foo.bar');
     expect({ foo: { bar: 'baz' } })
         .to.not.have.property('foo.bar');
+    ({ foo: { bar: 'baz' } }).should.not.have.property('foo.bar');
 
     err(() => {
         expect('asd').to.have.property('foo');
+        'asd'.should.have.property('foo');
     }, 'expected \'asd\' to have a property \'foo\'');
     err(() => {
         expect({ foo: { bar: 'baz' } })
             .to.have.property('foo.bar');
+        ({ foo: { bar: 'baz' } }).should.have.property('foo.bar');
     }, 'expected { foo: { bar: \'baz\' } } to have a property \'foo.bar\'');
 }
 
 function deepProperty() {
     expect({ 'foo.bar': 'baz' })
         .to.not.have.deep.property('foo.bar');
+    ({ 'foo.bar': 'baz' }).should
+        .not.have.deep.property('foo.bar');
     expect({ foo: { bar: 'baz' } })
         .to.have.deep.property('foo.bar');
+    ({ foo: { bar: 'baz' } }).should
+        .have.deep.property('foo.bar');
 
     err(() => {
         expect({ 'foo.bar': 'baz' })
             .to.have.deep.property('foo.bar');
+        ({ 'foo.bar': 'baz' }).should
+            .have.deep.property('foo.bar');
     }, 'expected { \'foo.bar\': \'baz\' } to have a deep property \'foo.bar\'');
 }
 
 function property2() {
     expect('test').to.have.property('length', 4);
+    'test'.should.have.property('length', 4);
     expect('asd').to.have.property('constructor', String);
+    'asd'.should.have.property('constructor', String);
 
     err(() => {
         expect('asd').to.have.property('length', 4, 'blah');
+        'asd'.should.have.property('length', 4, 'blah');
     }, 'blah: expected \'asd\' to have a property \'length\' of 4, but got 3');
 
     err(() => {
         expect('asd').to.not.have.property('length', 3, 'blah');
+        'asd'.should.not.have.property('length', 3, 'blah');
     }, 'blah: expected \'asd\' to not have a property \'length\' of 3');
 
     err(() => {
         expect('asd').to.not.have.property('foo', 3, 'blah');
+        'asd'.should.not.have.property('foo', 3, 'blah');
     }, 'blah: \'asd\' has no property \'foo\'');
 
     err(() => {
         expect('asd').to.have.property('constructor', Number, 'blah');
+        'asd'.should.have.property('constructor', Number, 'blah');
     }, 'blah: expected \'asd\' to have a property \'constructor\' of [Function: Number], but got [Function: String]');
 }
 
 function deepProperty2() {
     expect({ foo: { bar: 'baz' } })
         .to.have.deep.property('foo.bar', 'baz');
+    ({ foo: { bar: 'baz' } }).should
+        .have.deep.property('foo.bar', 'baz');
 
     err(() => {
         expect({ foo: { bar: 'baz' } })
             .to.have.deep.property('foo.bar', 'quux', 'blah');
+        ({ foo: { bar: 'baz' } }).should
+            .have.deep.property('foo.bar', 'quux', 'blah');
     }, 'blah: expected { foo: { bar: \'baz\' } } to have a deep property \'foo.bar\' of \'quux\', but got \'baz\'');
     err(() => {
         expect({ foo: { bar: 'baz' } })
             .to.not.have.deep.property('foo.bar', 'baz', 'blah');
+        ({ foo: { bar: 'baz' } }).should
+            .not.have.deep.property('foo.bar', 'baz', 'blah');
     }, 'blah: expected { foo: { bar: \'baz\' } } to not have a deep property \'foo.bar\' of \'baz\'');
     err(() => {
         expect({ foo: 5 })
             .to.not.have.deep.property('foo.bar', 'baz', 'blah');
+        ({ foo: 5 }).should
+            .not.have.deep.property('foo.bar', 'baz', 'blah');
     }, 'blah: { foo: 5 } has no deep property \'foo.bar\'');
 }
 
 function ownProperty() {
     expect('test').to.have.ownProperty('length');
+    'test'.should.have.ownProperty('length');
     expect('test').to.haveOwnProperty('length');
+    'test'.should.haveOwnProperty('length');
     expect({ length: 12 }).to.have.ownProperty('length');
+    ({ length: 12 }).should.have.ownProperty('length');
 
     err(() => {
         expect({ length: 12 }).to.not.have.ownProperty('length', 'blah');
+        ({ length: 12 }).should.not.have.ownProperty('length', 'blah');
     }, 'blah: expected { length: 12 } to not have own property \'length\'');
 }
 
 function string() {
     expect('foobar').to.have.string('bar');
+    'foobar'.should.have.string('bar');
     expect('foobar').to.have.string('foo');
+    'foobar'.should.have.string('foo');
     expect('foobar').to.not.have.string('baz');
+    'foobar'.should.not.have.string('baz');
 
     err(() => {
         expect(3).to.have.string('baz');
+        (3).should.have.string('baz');
     }, 'expected 3 to be a string');
 
     err(() => {
         expect('foobar').to.have.string('baz', 'blah');
+        'foobar'.should.have.string('baz', 'blah');
     }, 'blah: expected \'foobar\' to contain \'baz\'');
 
     err(() => {
         expect('foobar').to.not.have.string('bar', 'blah');
+        'foobar'.should.not.have.string('bar', 'blah');
     }, 'blah: expected \'foobar\' to not contain \'bar\'');
 }
 
 function include() {
     expect(['foo', 'bar']).to.include('foo');
+    ['foo', 'bar'].should.include('foo');
     expect(['foo', 'bar']).to.include('foo');
+    ['foo', 'bar'].should.include('foo');
     expect(['foo', 'bar']).to.include('bar');
+    ['foo', 'bar'].should.include('bar');
     expect([1, 2]).to.include(1);
+    [1, 2].should.include(1);
     expect(['foo', 'bar']).to.not.include('baz');
+    ['foo', 'bar'].should.not.include('baz');
     expect(['foo', 'bar']).to.not.include(1);
+    ['foo', 'bar'].should.not.include(1);
 
     err(() => {
         expect(['foo']).to.include('bar', 'blah');
+        ['foo'].should.include('bar', 'blah');
     }, 'blah: expected [ \'foo\' ] to include \'bar\'');
 
     err(() => {
         expect(['bar', 'foo']).to.not.include('foo', 'blah');
+        ['bar', 'foo'].should.not.include('foo', 'blah');
     }, 'blah: expected [ \'bar\', \'foo\' ] to not include \'foo\'');
 }
 
 function keys() {
     expect({ foo: 1 }).to.have.keys(['foo']);
+    ({ foo: 1 }).should.have.keys(['foo']);
     expect({ foo: 1, bar: 2 }).to.have.keys(['foo', 'bar']);
+    ({ foo: 1, bar: 2 }).should.have.keys(['foo', 'bar']);
     expect({ foo: 1, bar: 2 }).to.have.keys('foo', 'bar');
+    ({ foo: 1, bar: 2 }).should.have.keys('foo', 'bar');
     expect({ foo: 1, bar: 2, baz: 3 }).to.contain.keys('foo', 'bar');
+    ({ foo: 1, bar: 2, baz: 3 }).should.contain.keys('foo', 'bar');
     expect({ foo: 1, bar: 2, baz: 3 }).to.contain.keys('bar', 'foo');
+    ({ foo: 1, bar: 2, baz: 3 }).should.contain.keys('bar', 'foo');
     expect({ foo: 1, bar: 2, baz: 3 }).to.contain.keys('baz');
+    ({ foo: 1, bar: 2, baz: 3 }).should.contain.keys('baz');
 
     expect({ foo: 1, bar: 2 }).to.contain.keys('foo');
+    ({ foo: 1, bar: 2 }).should.contain.keys('foo');
     expect({ foo: 1, bar: 2 }).to.contain.keys('bar', 'foo');
+    ({ foo: 1, bar: 2 }).should.contain.keys('bar', 'foo');
     expect({ foo: 1, bar: 2 }).to.contain.keys(['foo']);
+    ({ foo: 1, bar: 2 }).should.contain.keys(['foo']);
     expect({ foo: 1, bar: 2 }).to.contain.keys(['bar']);
+    ({ foo: 1, bar: 2 }).should.contain.keys(['bar']);
     expect({ foo: 1, bar: 2 }).to.contain.keys(['bar', 'foo']);
+    ({ foo: 1, bar: 2 }).should.contain.keys(['bar', 'foo']);
 
     expect({ foo: 1, bar: 2 }).to.not.have.keys('baz');
+    ({ foo: 1, bar: 2 }).should.not.have.keys('baz');
     expect({ foo: 1, bar: 2 }).to.not.have.keys('foo', 'baz');
+    ({ foo: 1, bar: 2 }).should.not.have.keys('foo', 'baz');
     expect({ foo: 1, bar: 2 }).to.not.contain.keys('baz');
+    ({ foo: 1, bar: 2 }).should.not.contain.keys('baz');
     expect({ foo: 1, bar: 2 }).to.not.contain.keys('foo', 'baz');
+    ({ foo: 1, bar: 2 }).should.not.contain.keys('foo', 'baz');
     expect({ foo: 1, bar: 2 }).to.not.contain.keys('baz', 'foo');
+    ({ foo: 1, bar: 2 }).should.not.contain.keys('baz', 'foo');
 
     err(() => {
         expect({ foo: 1 }).to.have.keys();
+        ({ foo: 1 }).should.have.keys();
     }, 'keys required');
 
     err(() => {
         expect({ foo: 1 }).to.have.keys([]);
+        ({ foo: 1 }).should.have.keys([]);
     }, 'keys required');
 
     err(() => {
         expect({ foo: 1 }).to.not.have.keys([]);
+        ({ foo: 1 }).should.not.have.keys([]);
     }, 'keys required');
 
     err(() => {
         expect({ foo: 1 }).to.contain.keys([]);
+        ({ foo: 1 }).should.contain.keys([]);
     }, 'keys required');
 
     err(() => {
         expect({ foo: 1 }).to.have.keys(['bar']);
+        ({ foo: 1 }).should.have.keys(['bar']);
     }, 'expected { foo: 1 } to have key \'bar\'');
 
     err(() => {
         expect({ foo: 1 }).to.have.keys(['bar', 'baz']);
+        ({ foo: 1 }).should.have.keys(['bar', 'baz']);
     }, 'expected { foo: 1 } to have keys \'bar\', and \'baz\'');
 
     err(() => {
         expect({ foo: 1 }).to.have.keys(['foo', 'bar', 'baz']);
+        ({ foo: 1 }).should.have.keys(['foo', 'bar', 'baz']);
     }, 'expected { foo: 1 } to have keys \'foo\', \'bar\', and \'baz\'');
 
     err(() => {
         expect({ foo: 1 }).to.not.have.keys(['foo']);
+        ({ foo: 1 }).should.not.have.keys(['foo']);
     }, 'expected { foo: 1 } to not have key \'foo\'');
 
     err(() => {
         expect({ foo: 1 }).to.not.have.keys(['foo']);
+        ({ foo: 1 }).should.not.have.keys(['foo']);
     }, 'expected { foo: 1 } to not have key \'foo\'');
 
     err(() => {
         expect({ foo: 1, bar: 2 }).to.not.have.keys(['foo', 'bar']);
+        ({ foo: 1, bar: 2 }).should.not.have.keys(['foo', 'bar']);
     }, 'expected { foo: 1, bar: 2 } to not have keys \'foo\', and \'bar\'');
 
     err(() => {
         expect({ foo: 1 }).to.not.contain.keys(['foo']);
+        ({ foo: 1 }).should.not.contain.keys(['foo']);
     }, 'expected { foo: 1 } to not contain key \'foo\'');
 
     err(() => {
         expect({ foo: 1 }).to.contain.keys('foo', 'bar');
+        ({ foo: 1 }).should.contain.keys('foo', 'bar');
     }, 'expected { foo: 1 } to contain keys \'foo\', and \'bar\'');
 }
 
 function chaining() {
     var tea = { name: 'chai', extras: ['milk', 'sugar', 'smile'] };
     expect(tea).to.have.property('extras').with.lengthOf(3);
+    tea.should.have.property('extras').with.lengthOf(3);
 
     err(() => {
         expect(tea).to.have.property('extras').with.lengthOf(4);
+        tea.should.have.property('extras').with.lengthOf(4);
     }, 'expected [ \'milk\', \'sugar\', \'smile\' ] to have a length of 4 but got 3');
 
     expect(tea).to.be.a('object').and.have.property('name', 'chai');
+    tea.should.be.a('object').and.have.property('name', 'chai');
 }
 
 class PoorlyConstructedError {}
@@ -607,97 +846,180 @@ function _throw() {
         , specificErrFn = () => { throw specificError; };
 
     expect(goodFn).to.not.throw();
+    goodFn.should.not.throw();
+    should.not.throw(goodFn);
     expect(goodFn).to.not.throw(Error);
+    goodFn.should.not.throw(Error);
+    should.not.throw(goodFn, Error);
     expect(goodFn).to.not.throw(specificError);
+    goodFn.should.not.throw(specificError);
+    should.not.throw(goodFn, specificError);
+
     expect(badFn).to.throw();
+    badFn.should.throw();
+    should.throw(badFn);
     expect(badFn).to.throw(Error);
+    badFn.should.throw(Error);
+    should.throw(badFn, Error);
     expect(badFn).to.not.throw(ReferenceError);
+    badFn.should.not.throw(ReferenceError);
+    should.not.throw(badFn, ReferenceError);
     expect(badFn).to.not.throw(specificError);
+    badFn.should.not.throw(specificError);
+    should.not.throw(badFn, specificError);
+
     expect(refErrFn).to.throw();
+    refErrFn.should.throw();
+    should.throw(refErrFn);
     expect(refErrFn).to.throw(ReferenceError);
+    refErrFn.should.throw(ReferenceError);
+    should.throw(refErrFn, ReferenceError);
     expect(refErrFn).to.throw(Error);
+    refErrFn.should.throw(Error);
+    should.throw(refErrFn, Error);
     expect(refErrFn).to.not.throw(TypeError);
+    refErrFn.should.not.throw(TypeError);
+    should.not.throw(refErrFn, TypeError);
     expect(refErrFn).to.not.throw(specificError);
+    refErrFn.should.not.throw(specificError);
+    should.not.throw(refErrFn, specificError);
+
     expect(ickyErrFn).to.throw();
+    ickyErrFn.should.throw();
+    should.throw(ickyErrFn);
     expect(ickyErrFn).to.throw(PoorlyConstructedError);
+    ickyErrFn.should.throw(PoorlyConstructedError);
+    should.throw(ickyErrFn, PoorlyConstructedError);
     expect(ickyErrFn).to.throw(Error);
+    ickyErrFn.should.throw(Error);
+    should.throw(ickyErrFn, Error);
     expect(ickyErrFn).to.not.throw(specificError);
+    ickyErrFn.should.not.throw(specificError);
+    should.not.throw(ickyErrFn, specificError);
     expect(specificErrFn).to.throw(specificError);
+    specificErrFn.should.throw(specificError);
+    should.throw(ickyErrFn, specificError);
 
     expect(badFn).to.throw(/testing/);
+    badFn.should.throw(/testing/);
+    should.throw(badFn, /testing/);
     expect(badFn).to.not.throw(/hello/);
+    badFn.should.not.throw(/hello/);
+    should.not.throw(badFn, /hello/);
     expect(badFn).to.throw('testing');
+    badFn.should.throw('testing');
+    should.throw(badFn, 'testing');
     expect(badFn).to.not.throw('hello');
+    badFn.should.not.throw('hello');
+    should.not.throw(badFn, 'hello');
 
     expect(badFn).to.throw(Error, /testing/);
+    badFn.should.throw(Error, /testing/);
+    should.throw(badFn, Error, /testing/);
     expect(badFn).to.throw(Error, 'testing');
+    badFn.should.throw(Error, 'testing');
+    should.throw(badFn, Error, 'testing');
 
     err(() => {
         expect(goodFn).to.throw();
+        goodFn.should.throw();
+        should.throw(goodFn);
     }, 'expected [Function] to throw an error');
 
     err(() => {
         expect(goodFn).to.throw(ReferenceError);
+        goodFn.should.throw(ReferenceError);
+        should.throw(goodFn, ReferenceError);
     }, 'expected [Function] to throw ReferenceError');
 
     err(() => {
         expect(goodFn).to.throw(specificError);
+        goodFn.should.throw(specificError);
+        should.throw(goodFn, specificError);
     }, 'expected [Function] to throw [RangeError: boo]');
 
     err(() => {
         expect(badFn).to.not.throw();
+        badFn.should.not.throw();
+        should.not.throw(badFn);
     }, 'expected [Function] to not throw an error but [Error: testing] was thrown');
 
     err(() => {
         expect(badFn).to.throw(ReferenceError);
+        badFn.should.throw(ReferenceError);
+        should.throw(badFn, ReferenceError);
     }, 'expected [Function] to throw \'ReferenceError\' but [Error: testing] was thrown');
 
     err(() => {
         expect(badFn).to.throw(specificError);
+        badFn.should.throw(specificError);
+        should.throw(badFn, specificError);
     }, 'expected [Function] to throw [RangeError: boo] but [Error: testing] was thrown');
 
     err(() => {
         expect(badFn).to.not.throw(Error);
+        badFn.should.not.throw(Error);
+        should.not.throw(badFn, Error);
     }, 'expected [Function] to not throw \'Error\' but [Error: testing] was thrown');
 
     err(() => {
         expect(refErrFn).to.not.throw(ReferenceError);
+        refErrFn.should.not.throw(ReferenceError);
+        should.not.throw(refErrFn, ReferenceError);
     }, 'expected [Function] to not throw \'ReferenceError\' but [ReferenceError: hello] was thrown');
 
     err(() => {
         expect(badFn).to.throw(PoorlyConstructedError);
+        badFn.should.throw(PoorlyConstructedError);
+        should.throw(badFn, PoorlyConstructedError);
     }, 'expected [Function] to throw \'PoorlyConstructedError\' but [Error: testing] was thrown');
 
     err(() => {
         expect(ickyErrFn).to.not.throw(PoorlyConstructedError);
+        ickyErrFn.should.not.throw(PoorlyConstructedError);
+        should.not.throw(ickyErrFn, PoorlyConstructedError);
     }, /^(expected \[Function\] to not throw 'PoorlyConstructedError' but)(.*)(PoorlyConstructedError|\{ Object \()(.*)(was thrown)$/);
 
     err(() => {
         expect(ickyErrFn).to.throw(ReferenceError);
+        ickyErrFn.should.throw(ReferenceError);
+        should.throw(ickyErrFn, ReferenceError);
     }, /^(expected \[Function\] to throw 'ReferenceError' but)(.*)(PoorlyConstructedError|\{ Object \()(.*)(was thrown)$/);
 
     err(() => {
         expect(specificErrFn).to.throw(new ReferenceError('eek'));
+        specificErrFn.should.throw(new ReferenceError('eek'));
+        should.throw(specificErrFn, new ReferenceError('eek'));
     }, 'expected [Function] to throw [ReferenceError: eek] but [RangeError: boo] was thrown');
 
     err(() => {
         expect(specificErrFn).to.not.throw(specificError);
+        specificErrFn.should.not.throw(specificError);
+        should.not.throw(specificErrFn, specificError);
     }, 'expected [Function] to not throw [RangeError: boo]');
 
     err(() => {
         expect(badFn).to.not.throw(/testing/);
+        badFn.should.not.throw(/testing/);
+        should.not.throw(badFn, /testing/);
     }, 'expected [Function] to throw error not matching /testing/');
 
     err(() => {
         expect(badFn).to.throw(/hello/);
+        badFn.should.throw(/hello/);
+        should.throw(badFn, /hello/);
     }, 'expected [Function] to throw error matching /hello/ but got \'testing\'');
 
     err(() => {
         expect(badFn).to.throw(Error, /hello/, 'blah');
+        badFn.should.throw(Error, /hello/, 'blah');
+        should.throw(badFn, Error, /hello/, 'blah');
     }, 'blah: expected [Function] to throw error matching /hello/ but got \'testing\'');
 
     err(() => {
         expect(badFn).to.throw(Error, 'hello', 'blah');
+        badFn.should.throw(Error, 'hello', 'blah');
+        should.throw(badFn, Error, 'hello', 'blah');
     }, 'blah: expected [Function] to throw error including \'hello\' but got \'testing\'');
 }
 
@@ -712,18 +1034,23 @@ function respondTo() {
     var bar = {};
 
     expect(Foo).to.respondTo('bar');
+    Foo.should.respondTo('bar');
     expect(Foo).to.not.respondTo('foo');
+    Foo.should.not.respondTo('foo');
     expect(Foo).itself.to.respondTo('func');
     expect(Foo).itself.not.to.respondTo('bar');
 
     expect(bar).to.respondTo('foo');
+    bar.should.respondTo('foo');
 
     err(() => {
         expect(Foo).to.respondTo('baz', 'constructor');
+        Foo.should.respondTo('baz', 'constructor');
     }, /^(constructor: expected)(.*)(\[Function: Foo\])(.*)(to respond to \'baz\')$/);
 
     err(() => {
         expect(bar).to.respondTo('baz', 'object');
+        bar.should.respondTo('baz', 'object');
     }, /^(object: expected)(.*)(\{ foo: \[Function\] \}|\{ Object \()(.*)(to respond to \'baz\')$/);
 }
 
@@ -733,43 +1060,62 @@ function satisfy() {
     }
 
     expect(1).to.satisfy(matcher);
+    (1).should.satisfy(matcher);
 
     err(() => {
         expect(2).to.satisfy(matcher, 'blah');
+        (2).should.satisfy(matcher, 'blah');
     }, 'blah: expected 2 to satisfy [Function: matcher]');
 }
 
 function closeTo() {
     expect(1.5).to.be.closeTo(1.0, 0.5);
+    (1.5).should.be.closeTo(1.0, 0.5);
     expect(10).to.be.closeTo(20, 20);
+    (10).should.be.closeTo(20, 20);
     expect(-10).to.be.closeTo(20, 30);
+    (-10).should.be.closeTo(20, 30);
 
     err(() => {
         expect(2).to.be.closeTo(1.0, 0.5, 'blah');
+        (2).should.be.closeTo(1.0, 0.5, 'blah');
     }, 'blah: expected 2 to be close to 1 +/- 0.5');
 
     err(() => {
         expect(-10).to.be.closeTo(20, 29, 'blah');
+        (-10).should.be.closeTo(20, 29, 'blah');
     }, 'blah: expected -10 to be close to 20 +/- 29');
 }
 
 function includeMembers() {
     expect([1, 2, 3]).to.include.members([]);
+    [1, 2, 3].should.include.members([]);
 
     expect([1, 2, 3]).to.include.members([3, 2]);
 
+    [1, 2, 3].should.include.members([3, 2]);
+
     expect([1, 2, 3]).to.not.include.members([8, 4]);
 
+    [1, 2, 3].should.not.include.members([8, 4]);
+
     expect([1, 2, 3]).to.not.include.members([1, 2, 3, 4]);
+
+    [1, 2, 3].should.not.include.members([1, 2, 3, 4]);
 }
 
 function sameMembers() {
     expect([5, 4]).to.have.same.members([4, 5]);
+    [5, 4].should.have.same.members([4, 5]);
     expect([5, 4]).to.have.same.members([5, 4]);
+    [5, 4].should.have.same.members([5, 4]);
 
     expect([5, 4]).to.not.have.same.members([]);
+    [5, 4].should.not.have.same.members([]);
     expect([5, 4]).to.not.have.same.members([6, 3]);
+    [5, 4].should.not.have.same.members([6, 3]);
     expect([5, 4]).to.not.have.same.members([5, 4, 2]);
+    [5, 4].should.not.have.same.members([5, 4, 2]);
 }
 
 function members() {
diff --git a/chai/chai.d.ts b/chai/chai.d.ts
index 1134b137da..f693582c59 100644
--- a/chai/chai.d.ts
+++ b/chai/chai.d.ts
@@ -1,12 +1,15 @@
 // Type definitions for chai 2.0.0
 // Project: http://chaijs.com/
-// Definitions by: Jed Mao <https://github.com/jedmao/>, Bart van der Schoor <https://github.com/Bartvds>
+// Definitions by: Jed Mao <https://github.com/jedmao/>,
+//                 Bart van der Schoor <https://github.com/Bartvds>,
+//                 Andrew Brown <https://github.com/AGBrown>
 // Definitions: https://github.com/borisyankov/DefinitelyTyped
 
 declare module Chai {
 
     interface ChaiStatic {
         expect: ExpectStatic;
+        should(): Should;
         /**
          * Provides a way to extend the internals of Chai
          */
@@ -25,6 +28,24 @@ declare module Chai {
         (target: any, message?: string): Assertion;
     }
 
+    interface ShouldAssertion {
+        equal(value1: any, value2: any, message?: string): void;
+        Throw: ShouldThrow;
+        throw: ShouldThrow;
+        exist(value: any, message?: string): void;
+    }
+
+    interface Should extends ShouldAssertion {
+        not: ShouldAssertion;
+        fail(actual: any, expected: any, message?: string, operator?: string): void;
+    }
+
+    interface ShouldThrow {
+        (actual: Function): void;
+        (actual: Function, expected: string|RegExp, message?: string): void;
+        (actual: Function, constructor: Error|Function, expected?: string|RegExp, message?: string): void;
+    }
+
     interface Assertion extends LanguageChains, NumericComparison, TypeComparison {
         not: Assertion;
         deep: Deep;
@@ -281,3 +302,7 @@ declare var chai: Chai.ChaiStatic;
 declare module "chai" {
     export = chai;
 }
+
+interface Object {
+    should: Chai.Assertion;
+}