diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 000000000..8cc966dfd
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,20 @@
+# editorconfig.org
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false
+
+[*.php]
+indent_style = tab
+indent_size = 4
+
+[*.{xml,xml.dist}]
+indent_size = 4
diff --git a/ActiveRecord.php b/ActiveRecord.php
index f7c04a4d5..0283b49b7 100644
--- a/ActiveRecord.php
+++ b/ActiveRecord.php
@@ -10,6 +10,7 @@
 require __DIR__.'/lib/Singleton.php';
 require __DIR__.'/lib/Config.php';
 require __DIR__.'/lib/Utils.php';
+require __DIR__.'/lib/DateTimeInterface.php';
 require __DIR__.'/lib/DateTime.php';
 require __DIR__.'/lib/Model.php';
 require __DIR__.'/lib/Table.php';
diff --git a/composer.json b/composer.json
index 48885d40b..63f932948 100644
--- a/composer.json
+++ b/composer.json
@@ -9,7 +9,7 @@
         "php": ">=5.3.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "3.7.*",
+        "phpunit/phpunit": "4.*",
         "pear/pear_exception": "1.0-beta1",
         "pear/log": "~1.12"
     },
diff --git a/lib/Column.php b/lib/Column.php
index 0bedc8b5a..3e583ef31 100644
--- a/lib/Column.php
+++ b/lib/Column.php
@@ -169,11 +169,17 @@ public function cast($value, $connection)
 				if (!$value)
 					return null;
 
-				if ($value instanceof DateTime)
+				$date_class = Config::instance()->get_date_class();
+
+				if ($value instanceof $date_class)
 					return $value;
 
 				if ($value instanceof \DateTime)
-					return new DateTime($value->format('Y-m-d H:i:s T'));
+					return $date_class::createFromFormat(
+						Connection::DATETIME_TRANSLATE_FORMAT,
+						$value->format(Connection::DATETIME_TRANSLATE_FORMAT),
+						$value->getTimezone()
+					);
 
 				return $connection->string_to_datetime($value);
 		}
diff --git a/lib/Config.php b/lib/Config.php
index 7fbcfcf09..378a5b2e3 100644
--- a/lib/Config.php
+++ b/lib/Config.php
@@ -72,6 +72,14 @@ class Config extends Singleton
 	 */
 	private $logger;
 
+	/**
+	 * Contains the class name for the Date class to use. Must have a public format() method and a
+	 * public static createFromFormat($format, $time) method
+	 *
+	 * @var string
+	 */
+	private $date_class = 'ActiveRecord\\DateTime';
+
 	/**
 	 * The format to serialize DateTime values into.
 	 *
@@ -289,6 +297,28 @@ public function get_logger()
 		return $this->logger;
 	}
 
+	public function set_date_class($date_class)
+	{
+		try {
+			$klass = Reflections::instance()->add($date_class)->get($date_class);
+		} catch (\ReflectionException $e) {
+			throw new ConfigException("Cannot find date class");
+		}
+
+		if (!$klass->hasMethod('format') || !$klass->getMethod('format')->isPublic())
+			throw new ConfigException('Given date class must have a "public format($format = null)" method');
+
+		if (!$klass->hasMethod('createFromFormat') || !$klass->getMethod('createFromFormat')->isPublic())
+			throw new ConfigException('Given date class must have a "public static createFromFormat($format, $time)" method');
+
+		$this->date_class = $date_class;
+	}
+
+	public function get_date_class()
+	{
+		return $this->date_class;
+	}
+
 	/**
 	 * @deprecated
 	 */
diff --git a/lib/Connection.php b/lib/Connection.php
index 0010cb490..486885bd4 100644
--- a/lib/Connection.php
+++ b/lib/Connection.php
@@ -20,6 +20,17 @@
 abstract class Connection
 {
 
+	/**
+	 * The DateTime format to use when translating other DateTime-compatible objects.
+	 *
+	 * NOTE!: The DateTime "format" used must not include a time-zone (name, abbreviation, etc) or offset.
+	 * Including one will cause PHP to ignore the passed in time-zone in the 3rd argument.
+	 * See bug: https://bugs.php.net/bug.php?id=61022
+	 *
+	 * @var string
+	 */
+	const DATETIME_TRANSLATE_FORMAT = 'Y-m-d\TH:i:s';
+
 	/**
 	 * The PDO connection object.
 	 * @var mixed
@@ -469,7 +480,7 @@ public function datetime_to_string($datetime)
 	 * Converts a string representation of a datetime into a DateTime object.
 	 *
 	 * @param string $string A datetime in the form accepted by date_create()
-	 * @return DateTime
+	 * @return object The date_class set in Config
 	 */
 	public function string_to_datetime($string)
 	{
@@ -479,7 +490,13 @@ public function string_to_datetime($string)
 		if ($errors['warning_count'] > 0 || $errors['error_count'] > 0)
 			return null;
 
-		return new DateTime($date->format(static::$datetime_format));
+		$date_class = Config::instance()->get_date_class();
+
+		return $date_class::createFromFormat(
+			static::DATETIME_TRANSLATE_FORMAT,
+			$date->format(static::DATETIME_TRANSLATE_FORMAT),
+			$date->getTimezone()
+		);
 	}
 
 	/**
diff --git a/lib/DateTime.php b/lib/DateTime.php
index 9b488236b..133d83856 100644
--- a/lib/DateTime.php
+++ b/lib/DateTime.php
@@ -33,7 +33,7 @@
  * @package ActiveRecord
  * @see http://php.net/manual/en/class.datetime.php
  */
-class DateTime extends \DateTime
+class DateTime extends \DateTime implements DateTimeInterface
 {
 	/**
 	 * Default format used for format() and __toString()
@@ -113,11 +113,40 @@ public static function get_format($format=null)
 		return $format;
 	}
 
+	/**
+	 * This needs to be overriden so it returns an instance of this class instead of PHP's \DateTime.
+	 * See http://php.net/manual/en/datetime.createfromformat.php
+	 */
+	public static function createFromFormat($format, $time, $tz = null)
+	{
+		$phpDate = $tz ? parent::createFromFormat($format, $time, $tz) : parent::createFromFormat($format, $time);
+		if (!$phpDate)
+			return false;
+		// convert to this class using the timestamp
+		$ourDate = new static(null, $phpDate->getTimezone());
+		$ourDate->setTimestamp($phpDate->getTimestamp());
+		return $ourDate;
+	}
+
 	public function __toString()
 	{
 		return $this->format();
 	}
 
+	/**
+	 * Handle PHP object `clone`.
+	 *
+	 * This makes sure that the object doesn't still flag an attached model as
+	 * dirty after cloning the DateTime object and making modifications to it.
+	 *
+	 * @return void
+	 */
+	public function __clone()
+	{
+		$this->model = null;
+		$this->attribute_name = null;
+	}
+
 	private function flag_dirty()
 	{
 		if ($this->model)
@@ -127,24 +156,49 @@ private function flag_dirty()
 	public function setDate($year, $month, $day)
 	{
 		$this->flag_dirty();
-		call_user_func_array(array($this,'parent::setDate'),func_get_args());
+		return parent::setDate($year, $month, $day);
 	}
 
-	public function setISODate($year, $week , $day=null)
+	public function setISODate($year, $week , $day = 1)
 	{
 		$this->flag_dirty();
-		call_user_func_array(array($this,'parent::setISODate'),func_get_args());
+		return parent::setISODate($year, $week, $day);
 	}
 
-	public function setTime($hour, $minute, $second=null)
+	public function setTime($hour, $minute, $second = 0)
 	{
 		$this->flag_dirty();
-		call_user_func_array(array($this,'parent::setTime'),func_get_args());
+		return parent::setTime($hour, $minute, $second);
 	}
 
 	public function setTimestamp($unixtimestamp)
 	{
 		$this->flag_dirty();
-		call_user_func_array(array($this,'parent::setTimestamp'),func_get_args());
+		return parent::setTimestamp($unixtimestamp);
 	}
-}
\ No newline at end of file
+
+	public function setTimezone($timezone)
+	{
+		$this->flag_dirty();
+		return parent::setTimezone($timezone);
+	}
+	
+	public function modify($modify)
+	{
+		$this->flag_dirty();
+		return parent::modify($modify);
+	}
+	
+	public function add($interval)
+	{
+		$this->flag_dirty();
+		return parent::add($interval);
+	}
+
+	public function sub($interval)
+	{
+		$this->flag_dirty();
+		return parent::sub($interval);
+	}
+
+}
diff --git a/lib/DateTimeInterface.php b/lib/DateTimeInterface.php
new file mode 100644
index 000000000..3e7ca3174
--- /dev/null
+++ b/lib/DateTimeInterface.php
@@ -0,0 +1,35 @@
+<?php
+/**
+ * @package ActiveRecord
+ */
+namespace ActiveRecord;
+
+/**
+ * Interface for the ActiveRecord\DateTime class so that ActiveRecord\Model->assign_attribute() will
+ * know to call attribute_of() on passed values. This is so the DateTime object can flag the model
+ * as dirty via $model->flag_dirty() when one of its setters is called.
+ *
+ * @package ActiveRecord
+ * @see http://php.net/manual/en/class.datetime.php
+ */
+interface DateTimeInterface
+{
+	/**
+	 * Indicates this object is an attribute of the specified model, with the given attribute name.
+	 *
+	 * @param Model $model The model this object is an attribute of
+	 * @param string $attribute_name The attribute name 
+	 * @return void
+	 */
+	public function attribute_of($model, $attribute_name);
+
+	/**
+	 * Formats the DateTime to the specified format.
+	 */
+	public function format($format=null);
+
+	/**
+	 * See http://php.net/manual/en/datetime.createfromformat.php
+	 */
+	public static function createFromFormat($format, $time, $tz = null);
+}
diff --git a/lib/Model.php b/lib/Model.php
index 69bdb562d..ca55e55bd 100644
--- a/lib/Model.php
+++ b/lib/Model.php
@@ -477,12 +477,19 @@ public function assign_attribute($name, $value)
 		}
 
 		// convert php's \DateTime to ours
-		if ($value instanceof \DateTime)
-			$value = new DateTime($value->format('Y-m-d H:i:s T'));
+		if ($value instanceof \DateTime) {
+			$date_class = Config::instance()->get_date_class();
+			if (!($value instanceof $date_class))
+				$value = $date_class::createFromFormat(
+					Connection::DATETIME_TRANSLATE_FORMAT,
+					$value->format(Connection::DATETIME_TRANSLATE_FORMAT),
+					$value->getTimezone()
+				);
+		}
 
-		// make sure DateTime values know what model they belong to so
-		// dirty stuff works when calling set methods on the DateTime object
-		if ($value instanceof DateTime)
+		if ($value instanceof DateTimeInterface)
+			// Tell the Date object that it's associated with this model and attribute. This is so it
+			// has the ability to flag this model as dirty if a field in the Date object changes.
 			$value->attribute_of($this,$name);
 
 		// only update the attribute if it isn't set or has changed
@@ -991,7 +998,7 @@ protected function cache_key()
 	 * Delete all using a string:
 	 *
 	 * <code>
-	 * YourModel::delete_all(array('conditions' => 'name = "Tito"));
+	 * YourModel::delete_all(array('conditions' => 'name = "Tito"'));
 	 * </code>
 	 *
 	 * An options array takes the following parameters:
diff --git a/lib/Serialization.php b/lib/Serialization.php
index 9285d5ed9..b4b9b324e 100644
--- a/lib/Serialization.php
+++ b/lib/Serialization.php
@@ -221,9 +221,10 @@ final protected function options_to_a($key)
 	 */
 	final public function to_a()
 	{
+		$date_class = Config::instance()->get_date_class();
 		foreach ($this->attributes as &$value)
 		{
-			if ($value instanceof \DateTime)
+			if ($value instanceof $date_class)
 				$value = $value->format(self::$DATETIME_FORMAT);
 		}
 		return $this->attributes;
diff --git a/lib/Table.php b/lib/Table.php
index 044b1455c..600bbe9d6 100644
--- a/lib/Table.php
+++ b/lib/Table.php
@@ -428,9 +428,10 @@ private function &process_data($hash)
 		if (!$hash)
 			return $hash;
 
+		$date_class = Config::instance()->get_date_class();
 		foreach ($hash as $name => &$value)
 		{
-			if ($value instanceof \DateTime)
+			if ($value instanceof $date_class || $value instanceof \DateTime)
 			{
 				if (isset($this->columns[$name]) && $this->columns[$name]->type == Column::DATE)
 					$hash[$name] = $this->conn->date_to_string($value);
@@ -518,7 +519,7 @@ private function set_associations()
 			foreach (wrap_strings_in_arrays($definitions) as $definition)
 			{
 				$relationship = null;
-				$definition += compact('namespace');
+				$definition += array('namespace' => $namespace);
 
 				switch ($name)
 				{
diff --git a/lib/Utils.php b/lib/Utils.php
index 3db34514c..3251f776c 100644
--- a/lib/Utils.php
+++ b/lib/Utils.php
@@ -241,7 +241,7 @@ public static function is_blank($var)
         '/(bu)s$/i'                => "$1ses",
         '/(alias)$/i'              => "$1es",
         '/(octop)us$/i'            => "$1i",
-        '/(ax|test)is$/i'          => "$1es",
+        '/(cris|ax|test)is$/i'     => "$1es",
         '/(us)$/i'                 => "$1es",
         '/s$/i'                    => "s",
         '/$/'                      => "s"
diff --git a/lib/Validations.php b/lib/Validations.php
index 322dea247..c2cec72b3 100644
--- a/lib/Validations.php
+++ b/lib/Validations.php
@@ -442,7 +442,7 @@ public function validates_format_of($attrs)
 			$attribute = $options[0];
 			$var = $this->model->$attribute;
 
-			if (is_null($options['with']) || !is_string($options['with']) || !is_string($options['with']))
+			if (is_null($options['with']) || !is_string($options['with']))
 				throw new ValidationsArgumentError('A regular expression must be supplied as the [with] option of the configuration array.');
 			else
 				$expression = $options['with'];
@@ -600,7 +600,7 @@ public function validates_uniqueness_of($attrs)
 				continue;
 			
 			$pk = $this->model->get_primary_key();
-			$pk_value = $this->model->$pk[0];
+			$pk_value = $this->model->{$pk[0]};
 
 			if (is_array($options[0]))
 			{
@@ -979,4 +979,4 @@ public function getIterator()
 	{
 		return new ArrayIterator($this->full_messages());
 	}
-}
\ No newline at end of file
+}
diff --git a/test/ActiveRecordTest.php b/test/ActiveRecordTest.php
index ee2748ac5..cc0eaf881 100644
--- a/test/ActiveRecordTest.php
+++ b/test/ActiveRecordTest.php
@@ -660,11 +660,20 @@ public function test_changing_empty_attribute_value_tracks_change() {
 		$this->assert_equals("The most fun", $changes['description'][1]);
 	}
 
-	public function test_assigning_php_datetime_gets_converted_to_ar_datetime()
+	public function test_assigning_php_datetime_gets_converted_to_date_class_with_defaults()
 	{
 		$author = new Author();
 		$author->created_at = $now = new \DateTime();
-		$this->assert_is_a("ActiveRecord\\DateTime",$author->created_at);
+		$this->assert_is_a("ActiveRecord\\DateTime", $author->created_at);
+		$this->assert_datetime_equals($now,$author->created_at);
+	}
+
+	public function test_assigning_php_datetime_gets_converted_to_date_class_with_custom_date_class()
+	{
+		ActiveRecord\Config::instance()->set_date_class('\\DateTime'); // use PHP built-in DateTime
+		$author = new Author();
+		$author->created_at = $now = new \DateTime();
+		$this->assert_is_a("DateTime", $author->created_at);
 		$this->assert_datetime_equals($now,$author->created_at);
 	}
 
diff --git a/test/ActiveRecordWriteTest.php b/test/ActiveRecordWriteTest.php
index e0f0c4523..c0351413d 100644
--- a/test/ActiveRecordWriteTest.php
+++ b/test/ActiveRecordWriteTest.php
@@ -424,4 +424,21 @@ public function test_update_all_with_limit_and_order()
 		$this->assert_equals(1, $num_affected);
 		$this->assert_true(strpos(Author::table()->last_sql, 'ORDER BY name asc LIMIT 1') !== false);
 	}
+
+	public function test_update_native_datetime()
+	{
+		$author = Author::create(array('name' => 'Blah Blah'));
+		$native_datetime = new \DateTime('1983-12-05');
+		$author->some_date = $native_datetime;
+		$this->assert_false($native_datetime === $author->some_date);
+	}
+
+	public function test_update_our_datetime()
+	{
+		$author = Author::create(array('name' => 'Blah Blah'));
+		$our_datetime = new DateTime('1983-12-05');
+		$author->some_date = $our_datetime;
+		$this->assert_true($our_datetime === $author->some_date);
+	}
+
 }
diff --git a/test/ColumnTest.php b/test/ColumnTest.php
index 71db768b0..c36dceeca 100644
--- a/test/ColumnTest.php
+++ b/test/ColumnTest.php
@@ -130,4 +130,32 @@ public function test_empty_and_null_datetime_strings_should_return_null()
 		$this->assert_equals(null,$column->cast(null,$this->conn));
 		$this->assert_equals(null,$column->cast('',$this->conn));
 	}
+
+	public function test_native_date_time_attribute_copies_exact_tz()
+	{
+		$dt = new \DateTime(null, new \DateTimeZone('America/New_York'));
+
+		$column = new Column();
+		$column->type = Column::DATETIME;
+
+		$dt2 = $column->cast($dt, $this->conn);
+
+		$this->assert_equals($dt->getTimestamp(), $dt2->getTimestamp());
+		$this->assert_equals($dt->getTimeZone(), $dt2->getTimeZone());
+		$this->assert_equals($dt->getTimeZone()->getName(), $dt2->getTimeZone()->getName());
+	}
+
+	public function test_ar_date_time_attribute_copies_exact_tz()
+	{
+		$dt = new DateTime(null, new \DateTimeZone('America/New_York'));
+
+		$column = new Column();
+		$column->type = Column::DATETIME;
+
+		$dt2 = $column->cast($dt, $this->conn);
+
+		$this->assert_equals($dt->getTimestamp(), $dt2->getTimestamp());
+		$this->assert_equals($dt->getTimeZone(), $dt2->getTimeZone());
+		$this->assert_equals($dt->getTimeZone()->getName(), $dt2->getTimeZone()->getName());
+	}
 }
diff --git a/test/ConfigTest.php b/test/ConfigTest.php
index 73451be14..518413f11 100644
--- a/test/ConfigTest.php
+++ b/test/ConfigTest.php
@@ -8,6 +8,17 @@ class TestLogger
 	private function log() {}
 }
 
+class TestDateTimeWithoutCreateFromFormat
+{
+   public function format($format=null) {}
+}
+
+class TestDateTime
+{
+   public function format($format=null) {}
+   public static function createFromFormat($format, $time) {}
+}
+
 class ConfigTest extends SnakeCase_PHPUnit_Framework_TestCase
 {
 	public function set_up()
@@ -79,6 +90,19 @@ public function test_set_model_directories_must_be_array()
 		$this->config->set_model_directories(null);
 	}
 
+	public function test_get_date_class_with_default()
+	{
+		$this->assert_equals('ActiveRecord\\DateTime', $this->config->get_date_class());
+	}
+
+	/**
+	 * @expectedException ActiveRecord\ConfigException
+	 */
+	public function test_set_date_class_when_class_doesnt_exist()
+	{
+		$this->config->set_date_class('doesntexist');
+	}
+
 	/**
 	 * @expectedException ActiveRecord\ConfigException
 	 */
@@ -114,6 +138,28 @@ public function test_get_model_directory_returns_first_model_directory(){
 		ActiveRecord\Config::instance()->set_model_directory($home);
 	}
 
+	/**
+	 * @expectedException ActiveRecord\ConfigException
+	 */
+	public function test_set_date_class_when_class_doesnt_have_format_or_createfromformat()
+	{
+		$this->config->set_date_class('TestLogger');
+	}
+
+	/**
+	 * @expectedException ActiveRecord\ConfigException
+	 */
+	public function test_set_date_class_when_class_doesnt_have_createfromformat()
+	{
+		$this->config->set_date_class('TestDateTimeWithoutCreateFromFormat');
+	}
+
+	public function test_set_date_class_with_valid_class()
+	{
+		$this->config->set_date_class('TestDateTime');
+		$this->assert_equals('TestDateTime', $this->config->get_date_class());
+	}
+
 	public function test_initialize_closure()
 	{
 		$test = $this;
diff --git a/test/DateTimeTest.php b/test/DateTimeTest.php
index e489e0f74..3518db782 100644
--- a/test/DateTimeTest.php
+++ b/test/DateTimeTest.php
@@ -1,6 +1,6 @@
 <?php
-use ActiveRecord\DateTime as DateTime;
 use ActiveRecord\DatabaseException;
+use ActiveRecord\DateTime as DateTime;
 
 class DateTimeTest extends SnakeCase_PHPUnit_Framework_TestCase
 {
@@ -15,13 +15,20 @@ public function tear_down()
 		DateTime::$DEFAULT_FORMAT = $this->original_format;
 	}
 
-	private function assert_dirtifies($method /*, method params, ...*/)
+	private function get_model()
 	{
 		try {
 			$model = new Author();
 		} catch (DatabaseException $e) {
 			$this->mark_test_skipped('failed to connect. '.$e->getMessage());
 		}
+
+		return $model;
+	}
+
+	private function assert_dirtifies($method /*, method params, ...*/)
+	{
+		$model = $this->get_model();
 		$datetime = new DateTime();
 		$datetime->attribute_of($model,'some_date');
 
@@ -34,10 +41,16 @@ private function assert_dirtifies($method /*, method params, ...*/)
 
 	public function test_should_flag_the_attribute_dirty()
 	{
+		$interval = new DateInterval('PT1S');
+		$timezone = new DateTimeZone('America/New_York');
 		$this->assert_dirtifies('setDate',2001,1,1);
 		$this->assert_dirtifies('setISODate',2001,1);
 		$this->assert_dirtifies('setTime',1,1);
 		$this->assert_dirtifies('setTimestamp',1);
+		$this->assert_dirtifies('setTimezone',$timezone);
+		$this->assert_dirtifies('modify','+1 day');
+		$this->assert_dirtifies('add',$interval);
+		$this->assert_dirtifies('sub',$interval);
 	}
 
 	public function test_set_iso_date()
@@ -123,4 +136,80 @@ public function test_to_string()
 	{
 		$this->assert_equals(date(DateTime::get_format()), "" . $this->date);
 	}
+
+	public function test_create_from_format_error_handling()
+	{
+		$d = DateTime::createFromFormat('H:i:s Y-d-m', '!!!');
+		$this->assert_false($d);
+	}
+
+	public function test_create_from_format_without_tz()
+	{
+		$d = DateTime::createFromFormat('H:i:s Y-d-m', '03:04:05 2000-02-01');
+		$this->assert_equals(new DateTime('2000-01-02 03:04:05'), $d);
+	}
+
+	public function test_create_from_format_with_tz()
+	{
+		$d = DateTime::createFromFormat('Y-m-d H:i:s', '2000-02-01 03:04:05', new \DateTimeZone('Etc/GMT-10'));
+		$d2 = new DateTime('2000-01-31 17:04:05');
+
+		$this->assert_equals($d2->getTimestamp(), $d->getTimestamp());
+	}
+
+	public function test_native_date_time_attribute_copies_exact_tz()
+	{
+		$dt = new \DateTime(null, new \DateTimeZone('America/New_York'));
+		$model = $this->get_model();
+
+		// Test that the data transforms without modification
+		$model->assign_attribute('updated_at', $dt);
+		$dt2 = $model->read_attribute('updated_at');
+
+		$this->assert_equals($dt->getTimestamp(), $dt2->getTimestamp());
+		$this->assert_equals($dt->getTimeZone(), $dt2->getTimeZone());
+		$this->assert_equals($dt->getTimeZone()->getName(), $dt2->getTimeZone()->getName());
+	}
+
+	public function test_ar_date_time_attribute_copies_exact_tz()
+	{
+		$dt = new DateTime(null, new \DateTimeZone('America/New_York'));
+		$model = $this->get_model();
+
+		// Test that the data transforms without modification
+		$model->assign_attribute('updated_at', $dt);
+		$dt2 = $model->read_attribute('updated_at');
+
+		$this->assert_equals($dt->getTimestamp(), $dt2->getTimestamp());
+		$this->assert_equals($dt->getTimeZone(), $dt2->getTimeZone());
+		$this->assert_equals($dt->getTimeZone()->getName(), $dt2->getTimeZone()->getName());
+	}
+
+	public function test_clone()
+	{
+		$model = $this->get_model();
+		$model_attribute = 'some_date';
+
+		$datetime = new DateTime();
+		$datetime->attribute_of($model, $model_attribute);
+
+		$cloned_datetime = clone $datetime;
+
+		// Assert initial state
+		$this->assert_false($model->attribute_is_dirty($model_attribute));
+
+		$cloned_datetime->add(new DateInterval('PT1S'));
+
+		// Assert that modifying the cloned object didn't flag the model
+		$this->assert_false($model->attribute_is_dirty($model_attribute));
+
+		$datetime->add(new DateInterval('PT1S'));
+
+		// Assert that modifying the model-attached object did flag the model
+		$this->assert_true($model->attribute_is_dirty($model_attribute));
+
+		// Assert that the dates are equal but not the same instance
+		$this->assert_equals($datetime, $cloned_datetime);
+		$this->assert_not_same($datetime, $cloned_datetime);
+	}
 }
diff --git a/test/helpers/DatabaseTest.php b/test/helpers/DatabaseTest.php
index f3d26bc31..6cdcadd17 100644
--- a/test/helpers/DatabaseTest.php
+++ b/test/helpers/DatabaseTest.php
@@ -14,6 +14,8 @@ public function set_up($connection_name=null)
 		$config = ActiveRecord\Config::instance();
 		$this->original_default_connection = $config->get_default_connection();
 
+		$this->original_date_class = $config->get_date_class();
+
 		if ($connection_name)
 			$config->set_default_connection($connection_name);
 
@@ -42,6 +44,7 @@ public function set_up($connection_name=null)
 
 	public function tear_down()
 	{
+		ActiveRecord\Config::instance()->set_date_class($this->original_date_class);
 		if ($this->original_default_connection)
 			ActiveRecord\Config::instance()->set_default_connection($this->original_default_connection);
 	}