Testing, frameworks and deployment

PHPUnit and Pest, unit versus feature tests, a tour of Laravel and Symfony routing, and shipping with OPcache, PHP-FPM and zero-downtime releases.

Unit and feature tests

<?php
declare(strict_types=1);

use PHPUnit\Framework\TestCase;

final class SluggerTest extends TestCase
{
    public function test_it_slugifies_a_title(): void
    {
        self::assertSame("hello-world", (new Slugger())->slug("Hello World"));
    }

    public function test_it_rejects_an_empty_string(): void
    {
        $this->expectException(InvalidArgumentException::class);
        (new Slugger())->slug("   ");
    }
}

<?php
// Pest: the same two tests, with closures and expectations
it("slugifies a title", function () {
    expect((new Slugger())->slug("Hello World"))->toBe("hello-world");
});

it("rejects an empty string", function () {
    (new Slugger())->slug("   ");
})->throws(InvalidArgumentException::class);

• A unit test exercises one class with its collaborators replaced by test doubles; it is fast and says exactly what broke.
• A feature test goes through the router and asserts the response: $this->get("/health")->assertOk();.
• Test the behaviour you promised, not the private method you happen to have written. Refactoring should not break a test.
• One assertion of meaning per test reads better than five unrelated ones, and failures point at the cause rather than the symptom.

What a framework adds

<?php
// Laravel: routes, container, Eloquent
Route::get("/invoices/{invoice}", [InvoiceController::class, "show"]);

final class InvoiceController
{
    public function show(Invoice $invoice): JsonResponse
    {
        return response()->json($invoice->load("lines"));
    }
}

// Symfony: attribute routing with dependency injection
#[Route("/invoices/{id}", methods: ["GET"])]
public function show(int $id, InvoiceRepository $repo): Response
{
    return $this->json($repo->findOrFail($id));
}

• Both frameworks give you the same three things: a front controller, a way to map a URL to a handler, and a container that builds objects for you.
• Model binding converts a route parameter into an object and returns 404 when it does not exist, which replaces a recurring block of boilerplate.
• Migrations belong in version control with the code: a schema change and the query that needs it ship together.

Shipping it

# a release directory per build, switched with a symlink
composer install --no-dev --optimize-autoloader
php bin/console cache:warmup        # Laravel: php artisan optimize
ln -sfn /srv/releases/2026-09-18-1 /srv/current
systemctl reload php8.5-fpm         # new opcache, zero dropped requests

FAQ

Related

Composer, dependencies and coding standards Databases with PDO and prepared statements

Last refreshed 2026-09-18.