public function testConnect()
 {
     $env_vars = array('silverpop_ftp_host', 'silverpop_ftp_user', 'silverpop_ftp_password');
     foreach ($env_vars as $env_var) {
         $this->assertNotFalse(getenv($env_var), "Environment variable {$env_var} is not set.");
     }
     $silverpop = new \Kiva\Silverpop_Connector\SilverpopFTP();
     $dir_listing = $silverpop->ls();
     $this->assertTrue(in_array(\Kiva\Silverpop_Connector\SilverpopFTP::UPLOAD_DIRECTORY, $dir_listing));
 }