diff --git a/min/lib/Minify/ClosureCompiler.php b/min/lib/Minify/ClosureCompiler.php
index bdcdc7e..928bc80 100644
--- a/min/lib/Minify/ClosureCompiler.php
+++ b/min/lib/Minify/ClosureCompiler.php
@@ -33,6 +33,11 @@
  */
 class Minify_ClosureCompiler {
 
+    const OPTION_CHARSET = 'charset';
+    const OPTION_COMPILATION_LEVEL = 'compilation_level';
+
+    public static $isDebug = false;
+
     /**
      * Filepath of the Closure Compiler jar file. This must be set before
      * calling minifyJs().
@@ -70,13 +75,21 @@ class Minify_ClosureCompiler {
     {
         self::_prepare();
         if (! ($tmpFile = tempnam(self::$tempDir, 'cc_'))) {
-            throw new Exception('Minify_ClosureCompiler : could not create temp file in "'.self::$tempDir.'".');
+            throw new Minify_ClosureCompiler_Exception('Minify_ClosureCompiler : could not create temp file in "'.self::$tempDir.'".');
         }
         file_put_contents($tmpFile, $js);
-        exec(self::_getCmd($options, $tmpFile), $output, $result_code);
+        $cmd = self::_getCmd($options, $tmpFile);
+        $result = exec($cmd, $output, $result_code);
         unlink($tmpFile);
         if ($result_code != 0) {
-            throw new Exception('Minify_ClosureCompiler : Closure Compiler execution failed.');
+            $message = 'Minify_ClosureCompiler : Closure Compiler execution failed.';
+            if (self::$isDebug) { 
+                exec($cmd . ' 2>&1', $error);
+                if ($error) {
+                    $message .= "\nReason:\n" . join("\n", $error);
+                }
+            } 
+            throw new Minify_ClosureCompiler_Exception($message);
         }
         return implode("\n", $output);
     }
@@ -85,17 +98,18 @@ class Minify_ClosureCompiler {
     {
         $o = array_merge(
             array(
-                'charset' => 'utf-8',
-                'compilation_level' => 'SIMPLE_OPTIMIZATIONS',
+                self::OPTION_CHARSET => 'utf-8',
+                self::OPTION_COMPILATION_LEVEL => 'SIMPLE_OPTIMIZATIONS',
             ),
             $userOptions
         );
+        $charsetOption = $o[self::OPTION_CHARSET];
         $cmd = self::$javaExecutable . ' -jar ' . escapeshellarg(self::$jarFile)
-             . (preg_match('/^[\\da-zA-Z0-9\\-]+$/', $o['charset'])
-                ? " --charset {$o['charset']}"
+             . (preg_match('/^[\\da-zA-Z0-9\\-]+$/', $charsetOption)
+                ? " --charset {$charsetOption}"
                 : '');
 
-        foreach (array('compilation_level') as $opt) {
+        foreach (array(self::OPTION_COMPILATION_LEVEL) as $opt) {
             if ($o[$opt]) {
                 $cmd .= " --{$opt} ". escapeshellarg($o[$opt]);
             }
@@ -106,18 +120,18 @@ class Minify_ClosureCompiler {
     private static function _prepare()
     {
         if (! is_file(self::$jarFile)) {
-            throw new Exception('Minify_ClosureCompiler : $jarFile('.self::$jarFile.') is not a valid file.');
+            throw new Minify_ClosureCompiler_Exception('Minify_ClosureCompiler : $jarFile('.self::$jarFile.') is not a valid file.');
         }
         if (! is_readable(self::$jarFile)) {
-            throw new Exception('Minify_ClosureCompiler : $jarFile('.self::$jarFile.') is not readable.');
+            throw new Minify_ClosureCompiler_Exception('Minify_ClosureCompiler : $jarFile('.self::$jarFile.') is not readable.');
         }
         if (! is_dir(self::$tempDir)) {
-            throw new Exception('Minify_ClosureCompiler : $tempDir('.self::$tempDir.') is not a valid direcotry.');
+            throw new Minify_ClosureCompiler_Exception('Minify_ClosureCompiler : $tempDir('.self::$tempDir.') is not a valid direcotry.');
         }
         if (! is_writable(self::$tempDir)) {
-            throw new Exception('Minify_ClosureCompiler : $tempDir('.self::$tempDir.') is not writable.');
+            throw new Minify_ClosureCompiler_Exception('Minify_ClosureCompiler : $tempDir('.self::$tempDir.') is not writable.');
         }
     }
 }
 
-/* vim:ts=4:sw=4:et */
+class Minify_ClosureCompiler_Exception extends Exception {}
diff --git a/min_unit_tests/test_Minify_ClosureCompiler.php b/min_unit_tests/test_Minify_ClosureCompiler.php
new file mode 100644
index 0000000..ee3467d
--- /dev/null
+++ b/min_unit_tests/test_Minify_ClosureCompiler.php
@@ -0,0 +1,75 @@
+<?php
+require_once '_inc.php';
+
+function test_Minify_ClosureCompiler()
+{
+    global $thisDir;
+    Minify_ClosureCompiler::$isDebug = true;
+
+
+    // --- Test minification w/o setting the necessary settings ---
+    try {
+        Minify_ClosureCompiler::minify('');
+    } catch (Exception $e) {
+        $exc = $e;
+    }
+    $passed = assertTrue(
+        $exc instanceof Minify_ClosureCompiler_Exception
+        , 'Minify_ClosureCompiler : Throws Minify_ClosureCompiler_Exception');
+
+    if (__FILE__ === realpath($_SERVER['SCRIPT_FILENAME'])) {
+        echo "\n---Message: " . var_export($exc->getMessage(), 1) . "\n\n\n";
+    }
+    
+    $compiler_jar_path = __DIR__ . DIRECTORY_SEPARATOR . 'compiler.jar';
+    if (is_file($compiler_jar_path)) {
+
+        // set minimum necessary settings
+        Minify_ClosureCompiler::$jarFile = $compiler_jar_path;
+        Minify_ClosureCompiler::$tempDir = sys_get_temp_dir();
+        
+
+        // --- Test minification with the minimum necessary settings ---
+        
+        $src = "
+    (function (window, undefined){
+        function addOne(input) {
+            return 1 + input;
+        }
+        window.addOne = addOne;
+        window.undefined = undefined;
+    })(window);
+        ";
+        $minExpected = "(function(a,b){a.addOne=function(a){return 1+a};a.undefined=b})(window);";
+        $minOutput = Minify_ClosureCompiler::minify($src);
+        $passed = assertTrue($minExpected == $minOutput, 'Minify_ClosureCompiler : minimum necessary settings');
+        if (__FILE__ === realpath($_SERVER['SCRIPT_FILENAME'])) {
+            echo "\n---Output: " .countBytes($minOutput). " bytes\n\n{$minOutput}\n\n";
+            echo "---Expected: " .countBytes($minExpected). " bytes\n\n{$minExpected}\n\n";
+            echo "---Source: " .countBytes($src). " bytes\n\n{$src}\n\n\n";
+        }
+
+
+        // --- Test minifaction with advanced compilation level ---
+
+        $src = "function unused() {};";
+        $minExpected = '';
+        $minOutput = Minify_ClosureCompiler::minify($src, array(
+            Minify_ClosureCompiler::OPTION_COMPILATION_LEVEL => 'ADVANCED_OPTIMIZATIONS'
+        ));
+        $passed = assertTrue($minExpected == $minOutput, 'Minify_ClosureCompiler : advanced optimizations');
+        if (__FILE__ === realpath($_SERVER['SCRIPT_FILENAME'])) {
+            echo "\n---Output: " .countBytes($minOutput). " bytes\n\n{$minOutput}\n\n";
+            echo "---Expected: " .countBytes($minExpected). " bytes\n\n{$minExpected}\n\n";
+            echo "---Source: " .countBytes($src). " bytes\n\n{$src}\n\n\n";
+        }
+
+    } else {
+        echo "NONE: Minify_ClosureCompiler : Please download a compiler.jar from
+                               https://code.google.com/p/closure-compiler/wiki/BinaryDownloads
+                               put it under '${compiler_jar_path}' and make it readable by your webserver
+                               to test more functionality\n";
+    }
+}
+
+test_Minify_ClosureCompiler();
diff --git a/min_unit_tests/test_all.php b/min_unit_tests/test_all.php
index caba028..c654b6a 100644
--- a/min_unit_tests/test_all.php
+++ b/min_unit_tests/test_all.php
@@ -9,6 +9,7 @@ require 'test_Minify_Cache_Memcache.php';
 require 'test_Minify_Cache_ZendPlatform.php';
 require 'test_Minify_CSS.php';
 require 'test_Minify_CSS_UriRewriter.php';
+require 'test_Minify_ClosureCompiler.php';
 require 'test_Minify_JS_ClosureCompiler.php';
 require 'test_Minify_YuiCSS.php';
 require 'test_Minify_CommentPreserver.php';