[2.0] Added unit tests for CLI Configuration. Fixed hasAttrbibute() issue of undefined property.

tests/Doctrine/Tests/Common/Cli/ConfigurationTest.php

+<?php
+
+namespace Doctrine\Tests\Common\Cli;
+
+use Doctrine\Common\Cli\Configuration;
+
+require_once __DIR__ . '/../../TestInit.php';
+
+class ConfigurationTest extends \Doctrine\Tests\DoctrineTestCase
+{
+    public function testConfiguration()
+    {
+        $config = new Configuration();
+        $config->setAttribute('name', 'value');
+        
+        $this->assertTrue($config->hasAttribute('name'));
+        $this->assertEquals('value', $config->hasAttribute('name'));
+        
+        $config->setAttribute('name');
+        
+        $this->assertFalse($config->hasAttribute('name'));
+    }
+}
\ No newline at end of file