Fully automate the module without requiring changes to tests

Start with the module's _before(TestInterface $test) entry point and the Codeception Di::injectDependencies call shown in the issue. Trace how Cest and other test types are executed, then define the lifecycle hook needed to run Mockery cleanup without test changes. Done means the module works across supported test types with coverage for cleanup and failure handling.

Currently using this module requires changes in each test.
I have found an ugly way to alleviate that problem.

The code below was tested for Cest type tests only. It should not break for any other test type but might simply not work.

use Codeception\Lib\Di;
use Codeception\Module;
use Codeception\TestInterface;

class Mockery extends Module
{


    public function _before(TestInterface $test)
    {
        $meta = $test->getMetadata();
        $rc = new \ReflectionClass($meta);
        $prop = $rc->getProperty('services');
        $prop->setAccessible(true);
        $services = $prop->getValue($meta);
        /** @var Di $di */
        $di = $services['di'];

        $services['di'] = new class($di, $test) extends Di {
            public function __construct(Di $fallback, private readonly TestInterface $test)
            {
                parent::__construct($fallback);

            }


            public function injectDependencies(object $object, string $injectMethodName = self::DEFAULT_INJECT_METHOD_NAME, array $defaults = []): void
            {
                if ($object === $this->test) {
                    parent::injectDependencies(...func_get_args());
                    return;
                }
                // We check if the object is our test, if so we close mockery after.

                codecept_debug(['CALLING',
                    get_class($object),
                    $injectMethodName
                ]);
                try {
                    parent::injectDependencies(...func_get_args());
                    \Mockery::close();
                } catch (\Throwable $t) {
                    \Mockery::resetContainer();
                    throw $t;
                }
                \Mockery::close();
            }
        };
        $prop->setValue($meta, $services);
    }
}

Essentially we hijack the Di container and replace it with a custom implementation. Based on the fact that for Cest files the actual test is ran like this:

$this->getMetadata()->getService('di')->injectDependencies($this->testInstance, $methodName, $context);

We abuse this to insert a mockery closure after calling the test method.

While I'm happy to make a PR for this, I'm not sure it should be in an "official" repository. I probably don't have time to implement a proper fix where we add an event to allow modules to fail a test before it is finished.