public function testCwd()
 {
     $cmd = new Command('echo "$PWD"');
     $cmd->setCwdPath('/tmp');
     $cmd->runBlocking();
     $this->assertTrue($cmd->hasExecutionResult());
     $this->assertNotNull($cmd->getExecutionResult());
     $this->assertEquals($cmd->getExecutionResult()->getStderr(), '');
     $this->assertEquals($cmd->getExecutionResult()->getStdout(), '/tmp');
 }