diff --git a/src/php/Phix_Project/ContractLib/Contract.php b/src/php/Phix_Project/ContractLib/Contract.php
new file mode 100644
index 0000000..4a0a43f
--- /dev/null
+++ b/src/php/Phix_Project/ContractLib/Contract.php
@@ -0,0 +1,274 @@
+<?php
+
+/**
+ * Copyright (c) 2011 Stuart Herbert.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *
+ *   * Neither the name of the copyright holders nor the names of the
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @package     Phix_Project
+ * @subpackage  ContractLib
+ * @author      Stuart Herbert <stuart@stuartherbert.com>
+ * @copyright   2011 Stuart Herbert
+ * @license     http://www.opensource.org/licenses/bsd-license.php  BSD License
+ * @link        http://phix-project.org
+ * @version     @@PACKAGE_VERSION@@
+ */
+
+namespace Phix_Project\ContractLib;
+
+class Contract
+{
+        /**
+         * Are we currently enforcing any contracts passed to 
+         * self::Enforce()?
+         * 
+         * By default, we do not!
+         * 
+         * @var boolean
+         */
+        static protected $enforcing = false;                
+        
+        /**
+         * Stateless library; cannot instantiate
+         */
+        protected function __construct()
+        {
+                // do nothing
+        }
+        
+        /**
+         * Precondition: is the expression $expr true?
+         * 
+         * Use this method at the start of your method to make sure you're
+         * happy with the data that you have been passed, and with the
+         * current state of your object
+         * 
+         * Throws an E5xx_ContractPreconditionException if the parameter
+         * passed in is false
+         * 
+         * @throw E5xx_ContractPreconditionException
+         * @param boolean $expr 
+         */
+        static public function Requires($expr)
+        {
+                if (!$expr)
+                {
+                        throw new E5xx_ContractPreconditionException();
+                }
+        }
+        
+        /**
+         * Precondition: is the expression $expr true?
+         * 
+         * Use this method at the start of your method to make sure you're
+         * happy with the data that you have been passed, and with the
+         * current state of your object
+         * 
+         * Throws an E5xx_ContractPreconditionException if $expr is false,
+         * and adds $value to the exception's error message so that you
+         * can see which value failed the test
+         * 
+         * @param boolean $expr
+         * @param mixed $value 
+         */
+        static public function RequiresValue($expr, $value)
+        {
+                if (!$expr)
+                {
+                        throw new E5xx_ContractPreconditionException(true, $value);
+                }
+        }
+        
+        /**
+         * Postcondition: is the expression $expr true?
+         * 
+         * Use this method at the end of your method to make sure you're
+         * happy with the results before your method returns to the caller
+         * 
+         * Throws an E5xx_ContractPostconditionException if $expr is false.
+         * 
+         * @param boolean $expr 
+         */
+        static public function Ensures($expr)
+        {
+                if (!$expr)
+                {
+                        throw new E5xx_ContractPostconditionException();
+                }
+        }
+        
+        /**
+         * Postcondition: is the expression $expr true?
+         * 
+         * Use this method at the end of your method to make sure you're
+         * happy with the results before your method returns to the caller
+         * 
+         * Throws an E5xx_ContractPostConditionException if $expr is false,
+         * and adds $value to the exception's error message so that you
+         * can see which value failed the test
+         * 
+         * @param boolean $expr
+         * @param mixed $value 
+         */
+        static public function EnsuresValue($expr, $value)
+        {
+                if (!$expr)
+                {
+                        throw new E5xx_ContractPostconditionException(true, $value);
+                }
+        }
+        
+        /**
+         * Condition: is the expr $expr true?
+         * 
+         * Use this method in the middle of your method, to check the
+         * workings of your method before continuing.
+         * 
+         * Throws an E5xx_ContractConditionException if $expr is false.
+         * 
+         * @param type $expr 
+         */
+        static public function Asserts($expr)
+        {
+                if (!$expr)
+                {
+                        throw new E5xx_ContractConditionException();
+                }
+        }
+        
+        /**
+         * Condition: is the expr $expr true?
+         * 
+         * Use this method in the middle of your method, to check the
+         * workings of your method before continuing.
+         * 
+         * Throws an E5xx_ContractConditionException if $expr is false,
+         * and adds $value to the exception's error message so that you
+         * can see which value failed the test
+         * 
+         * @param boolean $expr 
+         * @param mixed $value
+         */
+        static public function AssertsValue($expr, $value)
+        {
+                if (!$expr)
+                {
+                        throw new E5xx_ContractConditionException(true, $value);
+                }
+        }
+        
+        /**
+         * 
+         * @param type $values
+         * @param type $callback 
+         */
+        static public function ForAll($values, $callback)
+        {
+                array_walk($values, $callback);
+        }
+
+        // ================================================================
+        //
+        // Wrapped contract support
+        //
+        // ----------------------------------------------------------------
+        
+        /**
+         * Tell us to enforce contracts passed to self::Enforce()
+         */
+        static public function EnforceWrappedContracts()
+        {
+                self::$enforcing = true;
+        }
+
+        /**
+         * Tell us to enforce only calls made directly to the individual
+         * contract conditions: Requires, Assert, Ensures et al
+         */
+        static public function EnforceOnlyDirectContracts()
+        {
+                self::$enforcing = false;
+        }
+        
+        /**
+         * Check a set of preconditions *if* we are enforcing wrapped
+         * contracts.
+         * 
+         * This exists as a performance boost, allowing us to leave
+         * contracts in the code even in production environments
+         * 
+         * @param callback $callback
+         * @param array $params 
+         */
+        static public function Preconditions($callback, $params = array())
+        {
+                if (self::$enforcing)
+                {
+                        call_user_func_array($callback, $params);
+                }
+        }
+        
+        /**
+         * Check a set of postconditions *if* we are enforcing wrapped
+         * contracts.
+         * 
+         * This exists as a performance boost, allowing us to leave
+         * contracts in the code even in production environments
+         * 
+         * @param callback $callback
+         * @param array $params 
+         */
+        static public function Postconditions($callback, $params = array())
+        {
+                if (self::$enforcing)
+                {
+                        call_user_func_array($callback, $params);
+                }
+        }
+        
+        /**
+         * Check a set of conditions mid-method *if* we are enforcing
+         * wrapped contracts.
+         * 
+         * This exists as a performance boost, allowing us to leave
+         * contracts in the code even in production environments
+         * 
+         * @param callback $callback
+         * @param array $params 
+         */
+        static public function Conditionals($callback, $params = array())
+        {
+                if (self::$enforcing)
+                {
+                        call_user_func_array($callback, $params);
+                }
+        }
+}
\ No newline at end of file
diff --git a/src/php/Phix_Project/ContractLib/ContractInvariant.php b/src/php/Phix_Project/ContractLib/ContractInvariant.php
new file mode 100644
index 0000000..a99e700
--- /dev/null
+++ b/src/php/Phix_Project/ContractLib/ContractInvariant.php
@@ -0,0 +1,55 @@
+<?php
+
+/**
+ * Copyright (c) 2011 Stuart Herbert.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *
+ *   * Neither the name of the copyright holders nor the names of the
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @package     Phix_Project
+ * @subpackage  ContractLib
+ * @author      Stuart Herbert <stuart@stuartherbert.com>
+ * @copyright   2011 Stuart Herbert
+ * @license     http://www.opensource.org/licenses/bsd-license.php  BSD License
+ * @link        http://phix-project.org
+ * @version     @@PACKAGE_VERSION@@
+ */
+
+namespace Phix_Project\ContractLib;
+
+interface ContractInvariant
+{
+        /**
+         * A test method that can be called at any time during the life
+         * of an object, which will run a series of assert()s to prove
+         * that the object is in a sane state
+         */
+        public function objectInvariant();
+}
\ No newline at end of file
diff --git a/src/php/Phix_Project/ContractLib/E5xx/ContractConditionException.php b/src/php/Phix_Project/ContractLib/E5xx/ContractConditionException.php
new file mode 100644
index 0000000..af07da9
--- /dev/null
+++ b/src/php/Phix_Project/ContractLib/E5xx/ContractConditionException.php
@@ -0,0 +1,63 @@
+<?php
+
+/**
+ * Copyright (c) 2011 Stuart Herbert.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *
+ *   * Neither the name of the copyright holders nor the names of the
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @package     Phix_Project
+ * @subpackage  ContractLib
+ * @author      Stuart Herbert <stuart@stuartherbert.com>
+ * @copyright   2011 Stuart Herbert
+ * @license     http://www.opensource.org/licenses/bsd-license.php  BSD License
+ * @link        http://phix-project.org
+ * @version     @@PACKAGE_VERSION@@
+ */
+
+namespace Phix_Project\ContractLib;
+
+/**
+ * This exception is thrown when an assert() statement fails
+ */
+class E5xx_ContractConditionException extends E5xx_ContractFailedException
+{
+        public function __construct($hasValue = false, $value = false)
+        {
+                if (!$hasValue)
+                {
+                        parent::__construct("Contract::Assert() failed");
+                }
+                else
+                {
+                        parent::__construct("Contract::AssertValue() failed with value '" . print_r($value, true) . "'");
+                }
+        }
+}
\ No newline at end of file
diff --git a/src/php/Phix_Project/ContractLib/E5xx/ContractFailedException.php b/src/php/Phix_Project/ContractLib/E5xx/ContractFailedException.php
new file mode 100644
index 0000000..6637927
--- /dev/null
+++ b/src/php/Phix_Project/ContractLib/E5xx/ContractFailedException.php
@@ -0,0 +1,58 @@
+<?php
+
+/**
+ * Copyright (c) 2011 Stuart Herbert.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *
+ *   * Neither the name of the copyright holders nor the names of the
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @package     Phix_Project
+ * @subpackage  ContractLib
+ * @author      Stuart Herbert <stuart@stuartherbert.com>
+ * @copyright   2011 Stuart Herbert
+ * @license     http://www.opensource.org/licenses/bsd-license.php  BSD License
+ * @link        http://phix-project.org
+ * @version     @@PACKAGE_VERSION@@
+ */
+
+namespace Phix_Project\ContractLib;
+
+use Phix_Project\ExceptionsLib\E5xx_InternalServerErrorException;
+
+/**
+ * This exception is thrown when an assert() statement fails
+ */
+class E5xx_ContractFailedException extends E5xx_InternalServerErrorException
+{
+        public function __construct($message)
+        {
+                parent::__construct($message);
+        }
+}
\ No newline at end of file
diff --git a/src/php/Phix_Project/ContractLib/E5xx/ContractPostconditionException.php b/src/php/Phix_Project/ContractLib/E5xx/ContractPostconditionException.php
new file mode 100644
index 0000000..b84b6b0
--- /dev/null
+++ b/src/php/Phix_Project/ContractLib/E5xx/ContractPostconditionException.php
@@ -0,0 +1,63 @@
+<?php
+
+/**
+ * Copyright (c) 2011 Stuart Herbert.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *
+ *   * Neither the name of the copyright holders nor the names of the
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @package     Phix_Project
+ * @subpackage  ContractLib
+ * @author      Stuart Herbert <stuart@stuartherbert.com>
+ * @copyright   2011 Stuart Herbert
+ * @license     http://www.opensource.org/licenses/bsd-license.php  BSD License
+ * @link        http://phix-project.org
+ * @version     @@PACKAGE_VERSION@@
+ */
+
+namespace Phix_Project\ContractLib;
+
+/**
+ * This exception is thrown when a contract's postcondition is not met
+ */
+class E5xx_ContractPostconditionException extends E5xx_ContractFailedException
+{
+        public function __construct($hasValue = false, $value = null)
+        {
+                if (!$hasValue)
+                {
+                        parent::__construct('Contract::Ensures() failed');
+                }
+                else
+                {
+                        parent::__construct("Contract::EnsuresValue() failed with value '" . print_r($value, true) . "'");
+                }
+        }
+}
\ No newline at end of file
diff --git a/src/php/Phix_Project/ContractLib/E5xx/ContractPreconditionException.php b/src/php/Phix_Project/ContractLib/E5xx/ContractPreconditionException.php
new file mode 100644
index 0000000..7d4e132
--- /dev/null
+++ b/src/php/Phix_Project/ContractLib/E5xx/ContractPreconditionException.php
@@ -0,0 +1,63 @@
+<?php
+
+/**
+ * Copyright (c) 2011 Stuart Herbert.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *
+ *   * Neither the name of the copyright holders nor the names of the
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @package     Phix_Project
+ * @subpackage  ContractLib
+ * @author      Stuart Herbert <stuart@stuartherbert.com>
+ * @copyright   2011 Stuart Herbert
+ * @license     http://www.opensource.org/licenses/bsd-license.php  BSD License
+ * @link        http://phix-project.org
+ * @version     @@PACKAGE_VERSION@@
+ */
+
+namespace Phix_Project\ContractLib;
+
+/**
+ * This exception is thrown when a contract's precondition is not met
+ */
+class E5xx_ContractPreconditionException extends E5xx_ContractFailedException
+{
+        public function __construct($hasValue = false, $value = null)
+        {
+                if (!$hasValue)
+                {
+                        parent::__construct("Contract::Requires() failed");
+                }
+                else
+                {
+                        parent::__construct("Contract::RequiresValue() failed with value '" . print_r($value, true) . "'");                        
+                }
+        }
+}
\ No newline at end of file
diff --git a/src/tests/unit-tests/php/Phix_Project/Contract/ContractTest.php b/src/tests/unit-tests/php/Phix_Project/Contract/ContractTest.php
new file mode 100644
index 0000000..8cc34d0
--- /dev/null
+++ b/src/tests/unit-tests/php/Phix_Project/Contract/ContractTest.php
@@ -0,0 +1,206 @@
+<?php
+
+/**
+ * Copyright (c) 2011 Stuart Herbert.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *
+ *   * Neither the name of the copyright holders nor the names of the
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @package     Phix_Project
+ * @subpackage  ContractLib
+ * @author      Stuart Herbert <stuart@stuartherbert.com>
+ * @copyright   2011 Stuart Herbert
+ * @license     http://www.opensource.org/licenses/bsd-license.php  BSD License
+ * @link        http://phix-project.org
+ * @version     @@PACKAGE_VERSION@@
+ */
+
+
+namespace Phix_Project\ContractLib;
+
+use Exception;
+use ReflectionClass;
+use PHPUnit_Framework_TestCase;
+
+use Phix_Project\ContractLib\Contract;
+
+class ContractTest extends PHPUnit_Framework_TestCase
+{
+        public function testCannotInstantiate()
+        {
+                $refClass = new ReflectionClass('Phix_Project\ContractLib\Contract');
+                $refMethod = $refClass->getMethod('__construct');
+                $this->assertFalse($refMethod->isPublic());
+        }
+        
+        /*
+        public function testCanInstantiate()
+        {
+                $obj = new Contract();
+                $this->assertTrue($obj instanceof Contract);
+        }
+        */
+        
+        public function testPreconditionsMustBeTrue()
+        {
+                // preconditional testing
+                Contract::Requires(true);
+                $this->assertTrue(true);
+                
+                $caughtException = false;
+                try
+                {
+                        Contract::Requires(false);
+                }
+                catch (E5xx_ContractPreconditionException $e)
+                {
+                        $caughtException = true;
+                }
+                $this->assertTrue($caughtException);
+        }
+
+        public function testPostconditionsMustBeTrue()
+        {
+                // postconditional testing
+                Contract::Ensures(true);
+                $this->assertTrue(true);
+                
+                $caughtException = false;
+                try
+                {
+                        Contract::Ensures(false);
+                }
+                catch (E5xx_ContractPostconditionException $e)
+                {
+                        $caughtException = true;
+                }
+                $this->assertTrue($caughtException);
+        }
+        
+        public function testCanApplyConditionsToArrays()
+        {
+                $testData1 = array (1,2,3,4,5);
+                $testData2 = array (6,7,8,9,10);
+
+                // these contracts are satisfied
+                Contract::ForAll($testData1, function($value) { Contract::Requires($value < 6); });
+                $this->assertTrue(true);
+                Contract::ForAll($testData2, function($value) { Contract::Requires($value > 5); });
+                $this->assertTrue(true);
+                
+                // these contracts are not satisfied
+                $caughtException = false;
+                try 
+                {
+                        Contract::ForAll($testData1, function($value) { Contract::Requires($value > 5); });
+                }
+                catch (E5xx_ContractPreconditionException $e)
+                {
+                        $caughtException = true;
+                }
+                $this->assertTrue($caughtException);
+
+                // these contracts are not satisfied
+                $caughtException = false;
+                try 
+                {
+                        Contract::ForAll($testData2, function($value) { Contract::Requires($value < 6); });
+                }
+                catch (E5xx_ContractPreconditionException $e)
+                {
+                        $caughtException = true;
+                }
+                $this->assertTrue($caughtException);
+        }
+        
+        public function testCanSeeTheValueThatFailedThePrecondition()
+        {
+                $caughtException = false;
+                try
+                {
+                        Contract::RequiresValue(false, 5);
+                }
+                catch (E5xx_ContractPreconditionException $e)
+                {
+                        $caughtException = $e->getMessage();
+                }
+                
+                // did we catch the exception?
+                $this->assertTrue($caughtException !== false);
+                
+                // did we get the message we expect?
+                $expected = "Internal server error: Contract::RequiresValue() failed with value '5'";
+                $this->assertEquals($expected, $caughtException);
+        }
+
+        public function testCanSeeTheValueThatFailedThePostcondition()
+        {
+                $caughtException = false;
+                try
+                {
+                        Contract::EnsuresValue(false, 5);
+                }
+                catch (E5xx_ContractPostconditionException $e)
+                {
+                        $caughtException = $e->getMessage();
+                }
+                
+                // did we catch the exception?
+                $this->assertTrue($caughtException !== false);
+                
+                // did we get the message we expect?
+                $expected = "Internal server error: Contract::EnsuresValue() failed with value '5'";
+                $this->assertEquals($expected, $caughtException);
+        }
+        
+        public function testCanWrapContractUpForPeformance()
+        {
+                Contract::EnforceWrappedContracts();
+                
+                $x = 1;
+                $y = 2;
+                $z = 3;
+                
+                Contract::Preconditions(function($x, $y, $z) {
+                        Contract::Requires($x < $y);
+                        Contract::Requires($y < $z);
+                }, array($x, $y, $z));
+                
+                Contract::Conditionals(function() {
+                        Contract::Asserts(2 > 1);
+                        Contract::Asserts(5 > 4);
+                });
+                
+                Contract::Postconditions(function($x, $y, $z) {
+                        Contract::Ensures($x < $z);
+                        Contract::Ensures($z > $x);
+                }, array($x, $y, $z));
+        }
+}
\ No newline at end of file