diff --git a/src/Common/XMLReader.php b/src/Common/XMLReader.php
index dc9ba74..aaf7c75 100644
--- a/src/Common/XMLReader.php
+++ b/src/Common/XMLReader.php
@@ -100,6 +100,25 @@ public function getElements($path, \DOMElement $contextNode = null)
         }
     }
 
+    /**
+     * Registers the namespace with the DOMXPath object
+     *
+     * @param string $prefix The prefix
+     * @param string $namespaceURI The URI of the namespace
+     * @return bool true on success or false on failure
+     * @throws \InvalidArgumentException If called before having loaded the DOM document
+     */
+    public function registerNamespace($prefix, $namespaceURI)
+    {
+        if ($this->dom === null) {
+            throw new \InvalidArgumentException('Dom needs to be loaded before registering a namespace');
+        }
+        if ($this->xpath === null) {
+            $this->xpath = new \DOMXpath($this->dom);
+        }
+        return $this->xpath->registerNamespace($prefix, $namespaceURI);
+    }
+
     /**
      * Get element
      *
diff --git a/tests/Common/Tests/XMLReaderTest.php b/tests/Common/Tests/XMLReaderTest.php
new file mode 100644
index 0000000..44019fd
--- /dev/null
+++ b/tests/Common/Tests/XMLReaderTest.php
@@ -0,0 +1,132 @@
+<?php
+/**
+ * This file is part of PHPOffice Common
+ *
+ * PHPOffice Common is free software distributed under the terms of the GNU Lesser
+ * General Public License version 3 as published by the Free Software Foundation.
+ *
+ * For the full copyright and license information, please read the LICENSE
+ * file that was distributed with this source code. For the full list of
+ * contributors, visit https://github.com/PHPOffice/Common/contributors.
+ *
+ * @link        https://github.com/PHPOffice/Common
+ * @copyright   2009-2017 PHPOffice Common contributors
+ * @license     http://www.gnu.org/licenses/lgpl.txt LGPL version 3
+ */
+
+namespace PhpOffice\Common\Tests;
+
+use PhpOffice\Common\XMLReader;
+
+/**
+ * Test class for XMLReader
+ *
+ * @coversDefaultClass PhpOffice\Common\XMLReader
+ */
+class XMLReaderTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * Test reading XML from string
+     */
+    public function testDomFromString()
+    {
+        $reader = new XMLReader();
+        $reader->getDomFromString('<element attr="test"><child attr="subtest">AAA</child></element>');
+
+        $this->assertTrue($reader->elementExists('/element/child'));
+        $this->assertEquals('AAA', $reader->getElement('/element/child')->textContent);
+        $this->assertEquals('AAA', $reader->getValue('/element/child'));
+        $this->assertEquals('test', $reader->getAttribute('attr', $reader->getElement('/element')));
+        $this->assertEquals('subtest', $reader->getAttribute('attr', $reader->getElement('/element'), 'child'));
+    }
+
+    /**
+     * Test reading XML from zip
+     */
+    public function testDomFromZip()
+    {
+        $pathResources = PHPOFFICE_COMMON_TESTS_BASE_DIR.DIRECTORY_SEPARATOR.'resources'.DIRECTORY_SEPARATOR.'files'.DIRECTORY_SEPARATOR;
+
+        $reader = new XMLReader();
+        $reader->getDomFromZip($pathResources. 'reader.zip', 'test.xml');
+
+        $this->assertTrue($reader->elementExists('/element/child'));
+
+        $this->assertFalse($reader->getDomFromZip($pathResources. 'reader.zip', 'non_existing_xml_file.xml'));
+    }
+
+    /**
+     * Test that read from non existing archive throws exception
+     *
+     * @expectedException Exception
+     */
+    public function testThrowsExceptionOnNonExistingArchive()
+    {
+        $pathResources = PHPOFFICE_COMMON_TESTS_BASE_DIR.DIRECTORY_SEPARATOR.'resources'.DIRECTORY_SEPARATOR.'files'.DIRECTORY_SEPARATOR;
+
+        $reader = new XMLReader();
+        $reader->getDomFromZip($pathResources. 'readers.zip', 'test.xml');
+    }
+
+    /**
+     * Test elements count
+     */
+    public function testCountElements()
+    {
+        $reader = new XMLReader();
+        $reader->getDomFromString('<element attr="test"><child>AAA</child><child>BBB</child></element>');
+
+        $this->assertEquals(2, $reader->countElements('/element/child'));
+    }
+
+    /**
+     * Test read non existing elements
+     */
+    public function testReturnNullOnNonExistingNode()
+    {
+        $reader = new XMLReader();
+        $this->assertEmpty($reader->getElements('/element/children'));
+        $reader->getDomFromString('<element><child>AAA</child></element>');
+
+        $this->assertNull($reader->getElement('/element/children'));
+        $this->assertNull($reader->getValue('/element/children'));
+    }
+
+    /**
+     * Test that xpath fails if custom namespace is not registered
+     *
+     * @expectedException Exception
+     */
+    public function testShouldThrowExceptionIfNamespaceIsNotKnown()
+    {
+        $reader = new XMLReader();
+        $reader->getDomFromString('<element><test:child xmlns:test="http://phpword.com/my/custom/namespace">AAA</test:child></element>');
+
+        $this->assertTrue($reader->elementExists('/element/test:child'));
+        $this->assertEquals('AAA', $reader->getElement('/element/test:child')->textContent);
+    }
+
+    /**
+     * Test reading XML with manually registered namespace
+     */
+    public function testShouldParseXmlWithCustomNamespace()
+    {
+        $reader = new XMLReader();
+        $reader->getDomFromString('<element><test:child xmlns:test="http://phpword.com/my/custom/namespace">AAA</test:child></element>');
+        $reader->registerNamespace('test', 'http://phpword.com/my/custom/namespace');
+
+        $this->assertTrue($reader->elementExists('/element/test:child'));
+        $this->assertEquals('AAA', $reader->getElement('/element/test:child')->textContent);
+    }
+
+    /**
+     * Test that xpath fails if custom namespace is not registered
+     *
+     * @expectedException InvalidArgumentException
+     */
+    public function testShouldThowExceptionIfTryingToRegisterNamespaceBeforeReadingDoc()
+    {
+        $reader = new XMLReader();
+        $reader->registerNamespace('test', 'http://phpword.com/my/custom/namespace');
+    }
+}
diff --git a/tests/resources/files/reader.zip b/tests/resources/files/reader.zip
new file mode 100644
index 0000000..dbe69cb
Binary files /dev/null and b/tests/resources/files/reader.zip differ