diff --git a/src/Escher/Escher.php b/src/Escher/Escher.php
index 5947c40..68f6583 100644
--- a/src/Escher/Escher.php
+++ b/src/Escher/Escher.php
@@ -18,7 +18,6 @@ class Escher
     const UNSIGNED_PAYLOAD = 'UNSIGNED-PAYLOAD';
 
     private $credentialScope;
-    private $date;
     private $clockSkew = self::DEFAULT_CLOCK_SKEW;
     private $hashAlgo = self::DEFAULT_HASH_ALGORITHM;
     private $algoPrefix = self::DEFAULT_ALGO_PREFIX;
@@ -26,15 +25,14 @@ class Escher
     private $authHeaderKey = self::DEFAULT_AUTH_HEADER_KEY;
     private $dateHeaderKey = self::DEFAULT_DATE_HEADER_KEY;
 
-    public function __construct($credentialScope, \DateTime $date)
+    public function __construct($credentialScope)
     {
         $this->credentialScope = $credentialScope;
-        $this->date = $date;
     }
 
-    public static function create($credentialScope, \DateTime $date = null)
+    public static function create($credentialScope)
     {
-        return new Escher($credentialScope, $date ? $date : self::now());
+        return new Escher($credentialScope);
     }
 
     /**
@@ -45,6 +43,13 @@ private static function now()
         return new \DateTime('now', new \DateTimeZone('GMT'));
     }
 
+    /**
+     * @param $keyDB
+     * @param array|null $serverVars
+     * @param null $requestBody
+     * @return mixed
+     * @throws Exception
+     */
     public function authenticate($keyDB, array $serverVars = null, $requestBody = null)
     {
         $serverVars = null === $serverVars ? $_SERVER : $serverVars;
@@ -63,15 +68,16 @@ public function authenticate($keyDB, array $serverVars = null, $requestBody = nu
         return $authElements->getAccessKeyId();
     }
 
-    public function presignUrl($accessKeyId, $secretKey, $url, $expires = Escher::DEFAULT_EXPIRES)
+    public function presignUrl($accessKeyId, $secretKey, $url, $expires = Escher::DEFAULT_EXPIRES, \DateTime $date = null)
     {
-        $url = $this->appendSigningParams($accessKeyId, $url, $this->date, $expires);
+        $date = $date ? $date : self::now();
+        $url = $this->appendSigningParams($accessKeyId, $url, $date, $expires);
 
         list($host, $path, $query) = $this->parseUrl($url);
 
         $signature = $this->calculateSignature(
             $secretKey,
-            $this->date,
+            $date,
             'GET',
             $path,
             $query,
@@ -84,18 +90,19 @@ public function presignUrl($accessKeyId, $secretKey, $url, $expires = Escher::DE
         return $url;
     }
 
-    public function signRequest($accessKeyId, $secretKey, $method, $url, $requestBody, $headerList = array(), $headersToSign = array())
+    public function signRequest($accessKeyId, $secretKey, $method, $url, $requestBody, $headerList = array(), $headersToSign = array(), \DateTime $date = null)
     {
+        $date = $date ? $date : self::now();
         list($host, $path, $query) = $this->parseUrl($url);
         list($headerList, $headersToSign) = $this->addMandatoryHeaders(
-            $headerList, $headersToSign, $this->dateHeaderKey, $this->date, $host
+            $headerList, $headersToSign, $this->dateHeaderKey, $date, $host
         );
 
         return $headerList + $this->generateAuthHeader(
             $secretKey,
             $accessKeyId,
             $this->authHeaderKey,
-            $this->date,
+            $date,
             $method,
             $path,
             $query,
diff --git a/test/unit/AuthenticateRequestTest.php b/test/unit/AuthenticateRequestTest.php
index de31c17..3d22156 100644
--- a/test/unit/AuthenticateRequestTest.php
+++ b/test/unit/AuthenticateRequestTest.php
@@ -8,6 +8,7 @@ class AuthenticateRequestTest extends TestBase
 {
     /**
      * @test
+     * @throws Exception
      */
     public function itShouldAuthenticateRequestUsingAuthHeader()
     {
@@ -32,6 +33,12 @@ public function itShouldAuthenticateRequestUsingAuthHeader()
     /**
      * @test
      * @dataProvider validPortProvider
+     * @param $httpHost
+     * @param $serverName
+     * @param $serverPort
+     * @param $https
+     * @param $signature
+     * @throws Exception
      */
     public function itShouldAuthenticateRequestRegardlessDefaultPortProvidedOrNot($httpHost, $serverName, $serverPort, $https, $signature)
     {
@@ -70,6 +77,11 @@ public function validPortProvider()
     /**
      * @test
      * @dataProvider requestTamperingProvider
+     * @param $tamperedKey
+     * @param $tamperedValue
+     * @param $expectedErrorMessage
+     * @param $expectedErrorCode
+     * @throws Exception
      */
     public function itShouldFailToValidateInvalidRequests($tamperedKey, $tamperedValue, $expectedErrorMessage, $expectedErrorCode)
     {
@@ -118,6 +130,7 @@ public function requestTamperingProvider()
 
     /**
      * @test
+     * @throws Exception
      */
     public function itShouldValidateRequestUsingQueryString()
     {
@@ -137,6 +150,7 @@ public function itShouldValidateRequestUsingQueryString()
 
     /**
      * @test
+     * @throws Exception
      */
     public function itShouldValidatePresignedUrlRequestWithSpecialCharacters()
     {
@@ -151,7 +165,7 @@ public function itShouldValidatePresignedUrlRequestWithSpecialCharacters()
             'SERVER_NAME'     => 'service.example.com',
         );
         $keyDB = array('service_api_key' => 'service_secret');
-        $this->createEscher('eu/service/ems_request', new \DateTime('20150310T173248Z', new \DateTimeZone('GMT')))->authenticate($keyDB, $serverVars);
+        $this->createEscher('eu/service/ems_request')->authenticate($keyDB, $serverVars);
     }
 
     /**
@@ -179,6 +193,7 @@ public function itShouldFailToValidateInvalidQueryStrings()
 
     /**
      * @test
+     * @throws Exception
      */
     public function itShouldValidatePresignedUrlRequestWithUnindexedArray()
     {
@@ -193,11 +208,12 @@ public function itShouldValidatePresignedUrlRequestWithUnindexedArray()
             'SERVER_NAME'     => 'service.example.com',
         );
         $keyDB = array('service_api_key' => 'service_secret');
-        $this->createEscher('eu/service/ems_request', new \DateTime('20150310T173248Z', new \DateTimeZone('GMT')))->authenticate($keyDB, $serverVars);
+        $this->createEscher('eu/service/ems_request')->authenticate($keyDB, $serverVars);
     }
 
     /**
      * @test
+     * @throws Exception
      */
     public function itShouldValidatePresignedUrlRequestWithIndexedArray()
     {
@@ -212,11 +228,12 @@ public function itShouldValidatePresignedUrlRequestWithIndexedArray()
             'SERVER_NAME'     => 'service.example.com',
         );
         $keyDB = array('service_api_key' => 'service_secret');
-        $this->createEscher('eu/service/ems_request', new \DateTime('20150310T173248Z', new \DateTimeZone('GMT')))->authenticate($keyDB, $serverVars);
+        $this->createEscher('eu/service/ems_request')->authenticate($keyDB, $serverVars);
     }
 
     /**
      * @test
+     * @throws Exception
      */
     public function itShouldValidatePresignedUrlIfSignatureIsTheFirstParam()
     {
@@ -231,11 +248,12 @@ public function itShouldValidatePresignedUrlIfSignatureIsTheFirstParam()
             'SERVER_NAME'     => 'service.example.com',
         );
         $keyDB = array('service_api_key' => 'service_secret');
-        $this->createEscher('eu/service/ems_request', new \DateTime('20150310T173248Z', new \DateTimeZone('GMT')))->authenticate($keyDB, $serverVars);
+        $this->createEscher('eu/service/ems_request')->authenticate($keyDB, $serverVars);
     }
 
     /**
      * @test
+     * @throws Exception
      */
     public function itShouldValidatePresignedUrlIfSignatureIsInTheMiddleOfTheQueryString()
     {
@@ -250,9 +268,14 @@ public function itShouldValidatePresignedUrlIfSignatureIsInTheMiddleOfTheQuerySt
             'SERVER_NAME'     => 'service.example.com',
         );
         $keyDB = array('service_api_key' => 'service_secret');
-        $this->createEscher('eu/service/ems_request', new \DateTime('20150310T173248Z', new \DateTimeZone('GMT')))->authenticate($keyDB, $serverVars);
+        $this->createEscher('eu/service/ems_request')->authenticate($keyDB, $serverVars);
     }
 
+    /**
+     * @param $dateString
+     * @return string
+     * @throws Exception
+     */
     private function strtotime($dateString)
     {
         return Utils::parseLongDate($dateString)->format('U');
diff --git a/test/unit/SignRequestUsingHeaderTest.php b/test/unit/SignRequestUsingHeaderTest.php
index 79a55a0..6874f78 100644
--- a/test/unit/SignRequestUsingHeaderTest.php
+++ b/test/unit/SignRequestUsingHeaderTest.php
@@ -21,7 +21,7 @@ public function itShouldSignRequest()
         $headersToSign =  array('content-type', 'host', 'x-ems-date');
         $actualHeaders = $this->createEscher('us-east-1/iam/aws4_request')->signRequest(
             'AKIDEXAMPLE', 'wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY',
-            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign
+            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign, $this->getDate()
         );
         $this->assertEqualMaps($expectedHeaders, $actualHeaders);
     }
@@ -47,7 +47,7 @@ public function itShouldSignRequestWithUppercaseHeader()
         $headersToSign =  array('content-type', 'host', 'x-ems-date', 'TEST');
         $actualHeaders = $this->createEscher('us-east-1/iam/aws4_request')->signRequest(
             'AKIDEXAMPLE', 'wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY',
-            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign
+            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign, $this->getDate()
         );
         $this->assertEqualMaps($expectedHeaders, $actualHeaders);
     }
@@ -70,7 +70,7 @@ public function itShouldAutomagicallyAddHostHeader()
         $headersToSign = array('content-type', 'host', 'x-ems-date');
         $actualHeaders = $this->createEscher('us-east-1/iam/aws4_request')->signRequest(
             'AKIDEXAMPLE', 'wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY',
-            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign
+            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign, $this->getDate()
         );
         $this->assertEqualMaps($expectedHeaders, $actualHeaders);
     }
@@ -88,7 +88,7 @@ public function itShouldAutomagicallyAddHostHeaderWithPort($url, $expectedHost)
         $headersToSign = array('content-type', 'host', 'x-ems-date');
         $actualHeaders = $this->createEscher('us-east-1/iam/aws4_request')->signRequest(
             'AKIDEXAMPLE', 'wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY',
-            'POST', $url, 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign
+            'POST', $url, 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign, $this->getDate()
         );
         $this->assertEquals($expectedHost, $actualHeaders['host']);
     }
@@ -125,7 +125,7 @@ public function itShouldAutomagicallyAddDateAndHostToSignedHeaders()
         $headersToSign = array('content-type');
         $actualHeaders = $this->createEscher('us-east-1/iam/aws4_request')->signRequest(
             'AKIDEXAMPLE', 'wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY',
-            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign
+            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign, $this->getDate()
         );
         $this->assertEqualMaps($expectedHeaders, $actualHeaders);
     }
@@ -151,7 +151,7 @@ public function itShouldOnlySignHeadersExplicitlySetToBeSigned()
         $headersToSign = array('content-type', 'host', 'x-ems-date');
         $actualHeaders = $this->createEscher('us-east-1/iam/aws4_request')->signRequest(
             'AKIDEXAMPLE', 'wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY',
-            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign
+            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign, $this->getDate()
         );
         $this->assertEqualMaps($expectedHeaders, $actualHeaders);
     }
@@ -175,7 +175,7 @@ public function itShouldUseTheProvidedAuthHeaderName()
         $headersToSign = array('content-type', 'host', 'x-ems-date');
         $actualHeaders = $this->createEscher('us-east-1/iam/aws4_request')->setAuthHeaderKey('Custom-Auth-Header')->signRequest(
             'AKIDEXAMPLE', 'wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY',
-            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign
+            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign, $this->getDate()
         );
         $this->assertEqualMaps($expectedHeaders, $actualHeaders);
     }
@@ -200,7 +200,7 @@ public function itShouldUseTheProvidedAlgoPrefix()
         $headersToSign = array('content-type', 'host', 'x-ems-date');
         $actualHeaders = $escher->signRequest(
             'AKIDEXAMPLE', 'wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY',
-            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign
+            'POST', 'http://iam.amazonaws.com/', 'Action=ListUsers&Version=2010-05-08', $inputHeaders, $headersToSign, $this->getDate()
         );
         $this->assertEqualMaps($expectedHeaders, $actualHeaders);
     }
@@ -216,11 +216,11 @@ public function itShouldGenerateSignedHeaders()
         );
 
         $date = new DateTime('2011/05/11 12:00:00', new DateTimeZone("UTC"));
-        $escher = $this->createEscher('us-east-1/host/aws4_request', $date);
+        $escher = $this->createEscher('us-east-1/host/aws4_request');
 
         $actualHeaders = $escher->signRequest(
             'th3K3y', 'very_secure',
-            'GET', 'http://example.com/something', '', $inputHeaders, array()
+            'GET', 'http://example.com/something', '', $inputHeaders, array(), $date
         );
 
         $expectedHeaders = array(
diff --git a/test/unit/SignRequestUsingQueryStringTest.php b/test/unit/SignRequestUsingQueryStringTest.php
index a0f26db..0718686 100644
--- a/test/unit/SignRequestUsingQueryStringTest.php
+++ b/test/unit/SignRequestUsingQueryStringTest.php
@@ -9,7 +9,7 @@ class SignRequestUsingQueryStringTest extends TestBase
      */
     public function itShouldGenerateSignedUrl()
     {
-        $signedUrl = $this->createEscher()->presignUrl('th3K3y', 'very_secure', 'http://example.com/something?foo=bar&baz=barbaz', $this->expires);
+        $signedUrl = $this->createEscher()->presignUrl('th3K3y', 'very_secure', 'http://example.com/something?foo=bar&baz=barbaz', $this->expires, $this->getDate());
 
         $expectedSignedUrl = 'http://example.com/something?foo=bar&baz=barbaz&X-EMS-Algorithm=EMS-HMAC-SHA256&X-EMS-Credentials=th3K3y%2F20110511%2Fus-east-1%2Fhost%2Faws4_request&X-EMS-Date=20110511T120000Z&X-EMS-Expires=123456&X-EMS-SignedHeaders=host&X-EMS-Signature=fbc9dbb91670e84d04ad2ae7505f4f52ab3ff9e192b8233feeae57e9022c2b67';
 
@@ -21,7 +21,7 @@ public function itShouldGenerateSignedUrl()
      */
     public function itShouldHandlePort()
     {
-        $signedUrl = $this->createEscher()->presignUrl('th3K3y', 'very_secure', 'http://example.com:5000/something?foo=bar&baz=barbaz', $this->expires);
+        $signedUrl = $this->createEscher()->presignUrl('th3K3y', 'very_secure', 'http://example.com:5000/something?foo=bar&baz=barbaz', $this->expires, $this->getDate());
 
         $expectedSignedUrl = 'http://example.com:5000/something?foo=bar&baz=barbaz&X-EMS-Algorithm=EMS-HMAC-SHA256&X-EMS-Credentials=th3K3y%2F20110511%2Fus-east-1%2Fhost%2Faws4_request&X-EMS-Date=20110511T120000Z&X-EMS-Expires=123456&X-EMS-SignedHeaders=host&X-EMS-Signature=7f7032b393945a0167fe65d35a7e2827a781ecab9019d814adf95c23bfa5e458';
 
@@ -33,7 +33,7 @@ public function itShouldHandlePort()
      */
     public function itShouldRespectWhenUrlHasLocationHash()
     {
-        $signedUrl = $this->createEscher()->presignUrl('th3K3y', 'very_secure', 'http://example.com:5000/something?foo=bar&baz=barbaz#/client_fragment', $this->expires);
+        $signedUrl = $this->createEscher()->presignUrl('th3K3y', 'very_secure', 'http://example.com:5000/something?foo=bar&baz=barbaz#/client_fragment', $this->expires, $this->getDate());
 
         $expectedSignedUrl = 'http://example.com:5000/something?foo=bar&baz=barbaz&X-EMS-Algorithm=EMS-HMAC-SHA256&X-EMS-Credentials=th3K3y%2F20110511%2Fus-east-1%2Fhost%2Faws4_request&X-EMS-Date=20110511T120000Z&X-EMS-Expires=123456&X-EMS-SignedHeaders=host&X-EMS-Signature=7f7032b393945a0167fe65d35a7e2827a781ecab9019d814adf95c23bfa5e458#/client_fragment';
 
@@ -45,10 +45,13 @@ public function itShouldRespectWhenUrlHasLocationHash()
      */
     public function itShouldRespectWhenUrlHasSpecialChars()
     {
-        $signedUrl = $this->createEscher('eu/service/ems_request', new DateTime('20150310T173248Z', new DateTimeZone('GMT')))->presignUrl(
+        $date = new DateTime('20150310T173248Z', new DateTimeZone('GMT'));
+        $signedUrl = $this->createEscher('eu/service/ems_request')->presignUrl(
             'service_api_key',
             'service_secret',
-            'https://service.example.com/login?id=12345678&domain=login.example.com&redirect_to=https%3A%2F%2Fhome.dev%2Fbootstrap.php%3Fr%3Dservice%2Findex%26service%3Dservice_name%3F'
+            'https://service.example.com/login?id=12345678&domain=login.example.com&redirect_to=https%3A%2F%2Fhome.dev%2Fbootstrap.php%3Fr%3Dservice%2Findex%26service%3Dservice_name%3F',
+            \Escher\Escher::DEFAULT_EXPIRES,
+            $date
         );
 
         $expectedSignedUrl = 'https://service.example.com/login?id=12345678&domain=login.example.com&redirect_to=https%3A%2F%2Fhome.dev%2Fbootstrap.php%3Fr%3Dservice%2Findex%26service%3Dservice_name%3F&X-EMS-Algorithm=EMS-HMAC-SHA256&X-EMS-Credentials=service_api_key%2F20150310%2Feu%2Fservice%2Fems_request&X-EMS-Date=20150310T173248Z&X-EMS-Expires=86400&X-EMS-SignedHeaders=host&X-EMS-Signature=661f2147c77b6784be5a60a8b842a96de6327653f1ed5d4305da43103c69a6f5';
diff --git a/test/unit/TestBase.php b/test/unit/TestBase.php
index 80a2678..862709b 100644
--- a/test/unit/TestBase.php
+++ b/test/unit/TestBase.php
@@ -13,16 +13,11 @@ protected function assertEqualMaps(array $expected, array $actual, $message = ''
 
     /**
      * @param string $credentialScope
-     * @param DateTime $date
      * @return Escher
      */
-    protected function createEscher($credentialScope = 'us-east-1/host/aws4_request', $date = null)
+    protected function createEscher($credentialScope = 'us-east-1/host/aws4_request')
     {
-        if (is_null($date))
-        {
-            $date = $this->getDate();
-        }
-        return Escher::create($credentialScope, $date)
+        return Escher::create($credentialScope)
             ->setAlgoPrefix('EMS')->setVendorKey('EMS')->setAuthHeaderKey('X-Ems-Auth')->setDateHeaderKey('X-Ems-Date');
     }