Dependencies Should Be Visible at Construction

Mon, 01 Jun 2020 00:00:00 +0000

This line created a database record:

$user = UserFactory::new()->create([
 'external_id' => 123,
]);

It also performed an HTTP request.

The factory did not mention a client. The model did not accept one. A synchronous observer noticed the external identifier, prepared a profile export, and resolved a connector from global framework state. The connector then looked up a remote account.

In tests without a fake, that lookup reached DNS or the network and retried three times with exponential backoff. Tests which had run in under five seconds took more than thirty. The slow test was annoying, but it was only the visible symptom. A local-looking construction operation had acquired an undeclared remote dependency.

Dependency-Injection on Brian Faust

Dependencies Should Be Visible at Construction