How to Test the Interaction of several Clients

If you need to simulate an interaction between different clients (think of a chat for instance), create several clients:

$harry = static::createClient();
$sally = static::createClient();

$harry->request('POST', '/say/sally/Hello');
$sally->request('GET', '/messages');

$this->assertEquals(201, $harry->getResponse()->getStatusCode());
$this->assertRegExp('/Hello/', $sally->getResponse()->getContent());

This works except when your code maintains a global state or if it depends on a third-party library that has some kind of global state. In such a case, you can insulate your clients:

$harry = static::createClient();
$sally = static::createClient();

$harry->insulate();
$sally->insulate();

$harry->request('POST', '/say/sally/Hello');
$sally->request('GET', '/messages');

$this->assertEquals(201, $harry->getResponse()->getStatusCode());
$this->assertRegExp('/Hello/', $sally->getResponse()->getContent());

Insulated clients transparently execute their requests in a dedicated and clean PHP process, thus avoiding any side-effects.

小技巧

As an insulated client is slower, you can keep one client in the main process, and insulate the other ones.