I have a controller that handles various cronjobs and I wanted to write unit tests for each function in the controller. The controller (lets call it TasksController) extends a base controller (let’s call it BaseController). Previously, I was creating new objects of individual Task classes inside each concerned function, but since that’s bad practice (ref1 ref2)that makes one’s code hard to test, I used DI container to inject dependencies instead. A sample function from Task Controller would look like:

<?php

namespace OrgControllers;

use DIContainer;
use OrgDbConnection;
use OrgLogger;
use OrgTasksSampleTask;

class TasksController extends BaseController
{
  public $container;

  // Task Objects:
  public $sampleTaskObject; 

  public function __construct(Container $container)
  {
    parent::__construct($container);
    $this->container = $container;
    // All objects for the task classes go below:
    $this->sampleTaskObject = $container->get(SampleTask::class);
  }

  function runSampleTaskObjectRun($request, $response, $args)
  {
    $this->sampleTaskObject->run();
    return $response->withStatus(200);
  }
}

The constructor for the base controller looks like:

class BaseController
{
  public $container;
  public $dbConn;
  public $logger;

  function __construct(Container $container)
  {
    $this->container = $container;
    $this->dbConn = $container->get(DbConnection::class);
    $this->logger = $container->get(Logger::class);
  }
}

In my unit tests, I am able to run tests by directly doing:

$this->container = $this->createMock(Container::class);
$this->tasksController = new TasksController($this->container);
$sampleTaskMockObject = $this->createMock(SampleTask::class);
$this->taskController->sampleTaskObject = $sampleTaskMockObject

However, I would like to use my DI container to inject this mock dependency to my controller instead (ideally without changing the control flow of my controller). I have looked at a few references online that mock dependencies, but couldn’t find one that does use container in a similar way.