public function testDefaultConfig()
 {
     $config = new Config(array(), 'http://example.com');
     $this->assertTrue($config->has('providers'), "The key 'providers' doesn't exist");
     $this->assertFalse($config->has('koalas'));
     $config->set('koalas', 'gum leaves');
     $this->assertSame('gum leaves', $config->get('koalas'));
 }