diff --git a/.travis.yml b/.travis.yml
index 9f4ca74c..18d8cbea 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,5 +5,9 @@ php:
   - 5.3
   - 5.4
 
+before_script:
+  - git clone git://github.com/zenovich/runkit.git && cd runkit && phpize && ./configure && make && make install && cd ..
+  - echo "extension=runkit.so" >> `php --ini | grep "Loaded Configuration" | sed -e "s|.*:\s*||"`
+
 script:
   - phpunit --verbose
diff --git a/tests/Crypt/AES/TestCase.php b/tests/Crypt/AES/TestCase.php
index d5884129..f845e4bb 100644
--- a/tests/Crypt/AES/TestCase.php
+++ b/tests/Crypt/AES/TestCase.php
@@ -5,7 +5,7 @@
  * @license    http://www.opensource.org/licenses/mit-license.html  MIT License
  */
 
-abstract class Crypt_AES_TestCase extends PHPUnit_Framework_TestCase
+abstract class Crypt_AES_TestCase extends PhpseclibTestCase
 {
 	static public function setUpBeforeClass()
 	{
diff --git a/tests/Crypt/Hash/TestCase.php b/tests/Crypt/Hash/TestCase.php
index 1489acd7..5f61244c 100644
--- a/tests/Crypt/Hash/TestCase.php
+++ b/tests/Crypt/Hash/TestCase.php
@@ -5,7 +5,7 @@
  * @license    http://www.opensource.org/licenses/mit-license.html  MIT License
  */
 
-abstract class Crypt_Hash_TestCase extends PHPUnit_Framework_TestCase
+abstract class Crypt_Hash_TestCase extends PhpseclibTestCase
 {
 	static public function setUpBeforeClass()
 	{
diff --git a/tests/Math/BigInteger/BCMathTest.php b/tests/Math/BigInteger/BCMathTest.php
new file mode 100644
index 00000000..08d4b3fe
--- /dev/null
+++ b/tests/Math/BigInteger/BCMathTest.php
@@ -0,0 +1,21 @@
+<?php
+/**
+ * @author     Andreas Fischer <bantu@phpbb.com>
+ * @copyright  MMXIII Andreas Fischer
+ * @license    http://www.opensource.org/licenses/mit-license.html  MIT License
+ */
+
+class Math_BigInteger_BCMathTest extends Math_BigInteger_TestCase
+{
+	static public function setUpBeforeClass()
+	{
+		if (!extension_loaded('bcmath'))
+		{
+			self::markTestSkipped('BCMath extension is not available.');
+		}
+
+		parent::setUpBeforeClass();
+
+		self::ensureModeConstant('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_BCMATH);
+	}
+}
diff --git a/tests/Math/BigInteger/GMPTest.php b/tests/Math/BigInteger/GMPTest.php
new file mode 100644
index 00000000..fcd898d1
--- /dev/null
+++ b/tests/Math/BigInteger/GMPTest.php
@@ -0,0 +1,21 @@
+<?php
+/**
+ * @author     Andreas Fischer <bantu@phpbb.com>
+ * @copyright  MMXIII Andreas Fischer
+ * @license    http://www.opensource.org/licenses/mit-license.html  MIT License
+ */
+
+class Math_BigInteger_GMPTest extends Math_BigInteger_TestCase
+{
+	static public function setUpBeforeClass()
+	{
+		if (!extension_loaded('gmp'))
+		{
+			self::markTestSkipped('GNU Multiple Precision (GMP) extension is not available.');
+		}
+
+		parent::setUpBeforeClass();
+
+		self::ensureModeConstant('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_GMP);
+	}
+}
diff --git a/tests/Math/BigInteger/InternalTest.php b/tests/Math/BigInteger/InternalTest.php
new file mode 100644
index 00000000..1ca2ef74
--- /dev/null
+++ b/tests/Math/BigInteger/InternalTest.php
@@ -0,0 +1,16 @@
+<?php
+/**
+ * @author     Andreas Fischer <bantu@phpbb.com>
+ * @copyright  MMXIII Andreas Fischer
+ * @license    http://www.opensource.org/licenses/mit-license.html  MIT License
+ */
+
+class Math_BigInteger_InternalTest extends Math_BigInteger_TestCase
+{
+	static public function setUpBeforeClass()
+	{
+		parent::setUpBeforeClass();
+
+		self::ensureModeConstant('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_INTERNAL);
+	}
+}
diff --git a/tests/Math/BigIntegerTest.php b/tests/Math/BigInteger/TestCase.php
similarity index 96%
rename from tests/Math/BigIntegerTest.php
rename to tests/Math/BigInteger/TestCase.php
index 1317609f..01edc475 100644
--- a/tests/Math/BigIntegerTest.php
+++ b/tests/Math/BigInteger/TestCase.php
@@ -5,8 +5,17 @@
  * @license    http://www.opensource.org/licenses/mit-license.html  MIT License
  */
 
-class Math_BigIntegerTest extends PHPUnit_Framework_TestCase
+require_once 'Math/BigInteger.php';
+
+abstract class Math_BigInteger_TestCase extends PhpseclibTestCase
 {
+	static public function setUpBeforeClass()
+	{
+		parent::setUpBeforeClass();
+
+		self::reRequireFile('Math/BigInteger.php');
+	}
+
 	public function getInstance($x = 0, $base = 10)
 	{
 		return new Math_BigInteger($x, $base);
diff --git a/tests/PhpseclibTestCase.php b/tests/PhpseclibTestCase.php
new file mode 100644
index 00000000..e69aa25a
--- /dev/null
+++ b/tests/PhpseclibTestCase.php
@@ -0,0 +1,74 @@
+<?php
+/**
+ * @author     Andreas Fischer <bantu@phpbb.com>
+ * @copyright  MMXIII Andreas Fischer
+ * @license    http://www.opensource.org/licenses/mit-license.html  MIT License
+ */
+
+abstract class PhpseclibTestCase extends PHPUnit_Framework_TestCase
+{
+	/**
+	* @param string $constant
+	* @param mixed $expected
+	*
+	* @return null
+	*/
+	static protected function ensureModeConstant($constant, $expected)
+	{
+		if (defined($constant))
+		{
+			$value = constant($constant);
+
+			if ($value !== $expected)
+			{
+				if (function_exists('runkit_constant_redefine'))
+				{
+					if (!runkit_constant_redefine($constant, $expected))
+					{
+						self::markTestSkipped(sprintf(
+							"Failed to redefine mode constant %s to %s",
+							$constant,
+							$expected
+						));
+					}
+				}
+				else
+				{
+					self::markTestSkipped(sprintf(
+						"Skipping test because mode constant %s is %s instead of %s",
+						$constant,
+						$value,
+						$expected
+					));
+				}
+			}
+		}
+		else
+		{
+			define($constant, $expected);
+		}
+	}
+
+	/**
+	* @param string $filename
+	*
+	* @return null
+	*/
+	static protected function reRequireFile($filename)
+	{
+		if (function_exists('runkit_import'))
+		{
+			$result = runkit_import(
+				$filename,
+				RUNKIT_IMPORT_FUNCTIONS |
+				RUNKIT_IMPORT_CLASS_METHODS |
+				RUNKIT_IMPORT_OVERRIDE
+			);
+
+			if (!$result)
+			{
+				self::markTestSkipped("Failed to reimport file $filename");
+			}
+		}
+	}
+}