diff --git a/tests/Math/BigInteger/BCMathTest.php b/tests/Math/BigInteger/BCMathTest.php
index 7d953b9e..6440550b 100644
--- a/tests/Math/BigInteger/BCMathTest.php
+++ b/tests/Math/BigInteger/BCMathTest.php
@@ -9,6 +9,11 @@ class Math_BigInteger_BCMathTest extends Math_BigInteger_TestCase
 {
 	static public function setUpBeforeClass()
 	{
+		if (!extension_loaded('bcmath'))
+		{
+			self::markTestSkipped('BCMath extension is not available.');
+		}
+
 		self::ensureModeConstant('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_BCMATH);
 		parent::setUpBeforeClass();
 	}
diff --git a/tests/Math/BigInteger/GMPTest.php b/tests/Math/BigInteger/GMPTest.php
index 2aea998b..c8895271 100644
--- a/tests/Math/BigInteger/GMPTest.php
+++ b/tests/Math/BigInteger/GMPTest.php
@@ -9,6 +9,11 @@ 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.');
+		}
+
 		self::ensureModeConstant('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_GMP);
 		parent::setUpBeforeClass();
 	}