diff --git a/core/lib/Thelia/TaxEngine/Calculator.php b/core/lib/Thelia/TaxEngine/Calculator.php
index ec6e3c78d..66c4fcbbf 100755
--- a/core/lib/Thelia/TaxEngine/Calculator.php
+++ b/core/lib/Thelia/TaxEngine/Calculator.php
@@ -69,28 +69,27 @@ class Calculator
 
     public function getTaxAmount($amount)
     {
-        if(false === filter_var($amount, FILTER_VALIDATE_FLOAT)) {
-            throw new TaxEngineException('BAD AMOUNT FORMAT', TaxEngineException::BAD_AMOUNT_FORMAT);
-        }
-
         if(null === $this->taxRulesGroupedCollection) {
             throw new TaxEngineException('Tax rules collection is empty in Calculator::getTaxAmount', TaxEngineException::UNDEFINED_TAX_RULES_COLLECTION);
         }
 
-        $taxRateAmount = 0;
-        foreach($this->taxRulesGroupedCollection as $taxRule) {
-            $taxRateAmount += $taxRule->getTaxRuleRateSum();
-        }
-
-        return $amount * $taxRateAmount * 0.01;
-    }
-
-    public function getTaxedPrice($amount)
-    {
         if(false === filter_var($amount, FILTER_VALIDATE_FLOAT)) {
             throw new TaxEngineException('BAD AMOUNT FORMAT', TaxEngineException::BAD_AMOUNT_FORMAT);
         }
 
+        $totalTaxAmount = 0;
+        foreach($this->taxRulesGroupedCollection as $taxRule) {
+            $rateSum = $taxRule->getTaxRuleRateSum();
+            $taxAmount = $amount * $rateSum * 0.01;
+            $totalTaxAmount += $taxAmount;
+            $amount += $taxAmount;
+        }
+
+        return $totalTaxAmount;
+    }
+
+    public function getTaxedPrice($amount)
+    {
         return $amount + $this->getTaxAmount($amount);
     }
 }
diff --git a/core/lib/Thelia/Tests/Rewriting/RewritingResolverTest.php b/core/lib/Thelia/Tests/Rewriting/RewritingResolverTest.php
index a3ec561d2..6cd4bdf42 100755
--- a/core/lib/Thelia/Tests/Rewriting/RewritingResolverTest.php
+++ b/core/lib/Thelia/Tests/Rewriting/RewritingResolverTest.php
@@ -61,7 +61,7 @@ class RewritingResolverTest extends \PHPUnit_Framework_TestCase
         $resolver = new RewritingResolver();
 
         $method = $this->getMethod('getOtherParameters');
-        $actual = $method->invoke($resolver);
+        $method->invoke($resolver);
     }
 
     public function testGetOtherParameters()
diff --git a/core/lib/Thelia/Tests/TaxEngine/CalculatorTest.php b/core/lib/Thelia/Tests/TaxEngine/CalculatorTest.php
new file mode 100755
index 000000000..fac6ca643
--- /dev/null
+++ b/core/lib/Thelia/Tests/TaxEngine/CalculatorTest.php
@@ -0,0 +1,169 @@
+<?php
+/*************************************************************************************/
+/*                                                                                   */
+/*      Thelia	                                                                     */
+/*                                                                                   */
+/*      Copyright (c) OpenStudio                                                     */
+/*      email : info@thelia.net                                                      */
+/*      web : http://www.thelia.net                                                  */
+/*                                                                                   */
+/*      This program is free software; you can redistribute it and/or modify         */
+/*      it under the terms of the GNU General Public License as published by         */
+/*      the Free Software Foundation; either version 3 of the License                */
+/*                                                                                   */
+/*      This program is distributed in the hope that it will be useful,              */
+/*      but WITHOUT ANY WARRANTY; without even the implied warranty of               */
+/*      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                */
+/*      GNU General Public License for more details.                                 */
+/*                                                                                   */
+/*      You should have received a copy of the GNU General Public License            */
+/*	    along with this program. If not, see <http://www.gnu.org/licenses/>.         */
+/*                                                                                   */
+/*************************************************************************************/
+
+namespace Thelia\Tests\TaxEngine;
+
+use Propel\Runtime\Collection\ObjectCollection;
+use Thelia\Model\Country;
+use Thelia\Model\CountryQuery;
+use Thelia\Model\Product;
+use Thelia\Model\ProductQuery;
+use Thelia\Model\Tax;
+use Thelia\TaxEngine\Calculator;
+
+/**
+ *
+ * @author Etienne Roudeix <eroudeix@openstudio.fr>
+ *
+ */
+class CalculatorTest extends \PHPUnit_Framework_TestCase
+{
+    protected function getMethod($name)
+    {
+        $class = new \ReflectionClass('\Thelia\TaxEngine\Calculator');
+        $method = $class->getMethod($name);
+        $method->setAccessible(true);
+
+        return $method;
+    }
+
+    protected function getProperty($name)
+    {
+        $class = new \ReflectionClass('\Thelia\TaxEngine\Calculator');
+        $property = $class->getProperty($name);
+        $property->setAccessible(true);
+
+        return $property;
+    }
+
+    /**
+     * @expectedException \Thelia\Exception\TaxEngineException
+     * @expectedExceptionCode 501
+     */
+    public function testLoadEmptyProductException()
+    {
+        $calculator = new Calculator();
+        $calculator->load(new Product(), CountryQuery::create()->findOne());
+    }
+
+    /**
+     * @expectedException \Thelia\Exception\TaxEngineException
+     * @expectedExceptionCode 502
+     */
+    public function testLoadEmptyCountryException()
+    {
+        $calculator = new Calculator();
+        $calculator->load(ProductQuery::create()->findOne(), new Country());
+    }
+
+    public function testLoad()
+    {
+        $productQuery = ProductQuery::create()->findOneById(1);
+        $countryQuery = CountryQuery::create()->findOneById(64);
+
+        $calculator = new Calculator();
+
+        $taxRuleQuery = $this->getMock('\Thelia\Model\TaxRuleQuery', array('getTaxCalculatorGroupedCollection'));
+        $taxRuleQuery->expects($this->once())
+            ->method('getTaxCalculatorGroupedCollection')
+            ->with($productQuery, $countryQuery)
+            ->will($this->returnValue('foo'));
+
+        $rewritingUrlQuery = $this->getProperty('taxRuleQuery');
+        $rewritingUrlQuery->setValue($calculator, $taxRuleQuery);
+
+        $calculator->load($productQuery, $countryQuery);
+
+        $this->assertEquals(
+            $productQuery,
+            $this->getProperty('product')->getValue($calculator)
+        );
+        $this->assertEquals(
+            $countryQuery,
+            $this->getProperty('country')->getValue($calculator)
+        );
+        $this->assertEquals(
+            'foo',
+            $this->getProperty('taxRulesGroupedCollection')->getValue($calculator)
+        );
+    }
+
+    /**
+     * @expectedException \Thelia\Exception\TaxEngineException
+     * @expectedExceptionCode 503
+     */
+    public function testGetTaxAmountBadTaxRulesCollection()
+    {
+        $calculator = new Calculator();
+        $calculator->getTaxAmount(500);
+    }
+
+    /**
+     * @expectedException \Thelia\Exception\TaxEngineException
+     * @expectedExceptionCode 601
+     */
+    public function testGetTaxAmountBadAmount()
+    {
+        $taxRulesGroupedCollection = new ObjectCollection();
+
+        $calculator = new Calculator();
+
+        $rewritingUrlQuery = $this->getProperty('taxRulesGroupedCollection');
+        $rewritingUrlQuery->setValue($calculator, $taxRulesGroupedCollection);
+
+        $calculator->getTaxAmount('foo');
+    }
+
+    public function testGetTaxAmountAndGetTaxedPrice()
+    {
+        $taxRulesGroupedCollection = new ObjectCollection();
+        $taxRulesGroupedCollection->setModel('\Thelia\Model\Tax');
+
+        $tax = new Tax();
+        $tax->setVirtualColumn('taxRateSum', 10);
+
+        $taxRulesGroupedCollection->append($tax);
+
+        $tax = new Tax();
+        $tax->setVirtualColumn('taxRateSum', 8);
+
+        $taxRulesGroupedCollection->append($tax);
+
+        $calculator = new Calculator();
+
+        $rewritingUrlQuery = $this->getProperty('taxRulesGroupedCollection');
+        $rewritingUrlQuery->setValue($calculator, $taxRulesGroupedCollection);
+
+        $taxAmount = $calculator->getTaxAmount(500);
+        $taxedPrice = $calculator->getTaxedPrice(500);
+
+        /*
+         * expect :
+         *  tax 1 = 500*0.10 = 50 // amout with tax 1 : 550
+         *  tax 2 = 550*0.08 = 44 // amout with tax 2 : 594
+         * total tax amount = 94
+         */
+        $this->assertEquals(94, $taxAmount);
+        $this->assertEquals(594, $taxedPrice);
+    }
+}