diff --git a/tests/Unit/Math/BigInteger/TestCase.php b/tests/Unit/Math/BigInteger/TestCase.php
index b0fab278..f8697e4e 100644
--- a/tests/Unit/Math/BigInteger/TestCase.php
+++ b/tests/Unit/Math/BigInteger/TestCase.php
@@ -465,5 +465,8 @@ abstract class Unit_Math_BigInteger_TestCase extends PhpseclibTestCase
     {
         $temp = $this->getInstance('00');
         $this->assertSame($temp->toString(), '0');
+
+        $temp = $this->getInstance('-0');
+        $this->assertSame($temp->toString(), '0');
     }
 }