diff --git a/.travis.yml b/.travis.yml
index 8983904d..9ae12b4a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,6 +8,7 @@ php:
   - 5.5
   - 5.6
   - 7.0
+  - hhvm
 
 env:
   global:
diff --git a/phpseclib/File/ASN1.php b/phpseclib/File/ASN1.php
index 0e67b217..180b0e67 100644
--- a/phpseclib/File/ASN1.php
+++ b/phpseclib/File/ASN1.php
@@ -616,7 +616,7 @@ class ASN1
                 }
 
                 // Fail mapping if all input items have not been consumed.
-                return $i < $n? null: $map;
+                return $i < $n ? null: $map;
 
             // the main diff between sets and sequences is the encapsulation of the foreach in another for loop
             case self::TYPE_SET:
diff --git a/phpseclib/Math/BigInteger.php b/phpseclib/Math/BigInteger.php
index 8ea9f1b2..9744275d 100644
--- a/phpseclib/Math/BigInteger.php
+++ b/phpseclib/Math/BigInteger.php
@@ -803,6 +803,39 @@ class BigInteger
         }
     }
 
+    /**
+     *  __debugInfo() magic method
+     *
+     * Will be called, automatically, when print_r() or var_dump() are called
+     *
+     * @access public
+     */
+    function __debugInfo()
+    {
+        $opts = array();
+        switch (MATH_BIGINTEGER_MODE) {
+            case MATH_BIGINTEGER_MODE_GMP:
+                $engine = 'gmp';
+                break;
+            case MATH_BIGINTEGER_MODE_BCMATH:
+                $engine = 'bcmath';
+                break;
+            case MATH_BIGINTEGER_MODE_INTERNAL:
+                $engine = 'internal';
+                $opts[] = PHP_INT_SIZE == 8 ? '64-bit' : '32-bit';
+        }
+        if (MATH_BIGINTEGER_MODE != MATH_BIGINTEGER_MODE_GMP && defined('MATH_BIGINTEGER_OPENSSL_ENABLED')) {
+            $opts[] = 'OpenSSL';
+        }
+        if (!empty($opts)) {
+            $engine.= ' (' . implode($opts, ', ') . ')';
+        }
+        return array(
+            'value' => '0x' . $this->toHex(true),
+            'engine' => $engine
+        );
+    }
+
     /**
      * Adds two BigIntegers.
      *
diff --git a/tests/Unit/Math/BigInteger/TestCase.php b/tests/Unit/Math/BigInteger/TestCase.php
index bb5293b3..1992fb8d 100644
--- a/tests/Unit/Math/BigInteger/TestCase.php
+++ b/tests/Unit/Math/BigInteger/TestCase.php
@@ -355,4 +355,15 @@ abstract class Unit_Math_BigInteger_TestCase extends PhpseclibTestCase
             'Failed asserting that Alice and Bob share the same BigInteger.'
         );
     }
+
+    /**
+     * @requires PHP 5.6
+     */
+    public function testDebugInfo()
+    {
+        $num = new Math_BigInteger(50);
+        $str = print_r($num, true);
+        $this->assertContains('[value] => 0x32', $str);
+        return $str;
+    }
 }
diff --git a/travis/install-php-extensions.sh b/travis/install-php-extensions.sh
index 2acfdfd7..5244261c 100755
--- a/travis/install-php-extensions.sh
+++ b/travis/install-php-extensions.sh
@@ -21,10 +21,5 @@ function install_php_extension
 }
 
 # runkit
-if [ "$TRAVIS_PHP_VERSION" == "5.6" ]
-then
-    git clone https://github.com/adrianguenter/runkit.git
-else
-    git clone https://github.com/zenovich/runkit.git
-fi
+git clone https://github.com/zenovich/runkit.git
 install_php_extension 'runkit'