单数据库单应用场景下，如何用paratest运行Dusk测试并生成4个应用实例？

Got it, let's break down how to get 4 parallel Dusk test instances running with Paratest, even with your single database and app setup. The key here is isolating each parallel process so they don't clash—here's a step-by-step guide:

1. Configure Isolated Databases for Each Parallel Process #

Since Dusk tests run in a real browser (external to your app's process), transaction rollbacks won't work for isolation. Instead, we'll create a unique test database for each Paratest process using the PARALLEL_TEST_TOKEN environment variable (automatically set by Paratest, starting from 0).

Update Your phpunit.dusk.xml #

Add a dynamic database name and app URL to your config:

<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="./vendor/phpunit/phpunit/phpunit.xsd"
         bootstrap="bootstrap/paratest_dusk.php"
         colors="true">
    <php>
        <!-- Unique database per parallel process -->
        <server name="DB_DATABASE" value="testing_${PARALLEL_TEST_TOKEN}"/>
        <!-- App URL with dynamic port for Docker network access -->
        <server name="APP_URL" value="http://app:800${PARALLEL_TEST_TOKEN}"/>
        <!-- Keep your existing DB credentials (DB_USERNAME, DB_PASSWORD, etc.) -->
    </php>
    <!-- Rest of your config... -->
</phpunit>

Auto-Create & Migrate Each Database #

Create a bootstrap script to initialize the database for each process. Save this as bootstrap/paratest_dusk.php:

<?php

require __DIR__.'/../vendor/autoload.php';

$token = getenv('PARALLEL_TEST_TOKEN') ?: 0;
$dbName = "testing_{$token}";

// Initialize Laravel app to use Artisan commands
$app = require_once __DIR__.'/../bootstrap/app.php';
$kernel = $app->make(Illuminate\Contracts\Console\Kernel::class);
$kernel->bootstrap();

// Create the database if it doesn't exist
try {
    \Illuminate\Support\Facades\DB::connection()->statement("CREATE DATABASE IF NOT EXISTS {$dbName}");
} catch (\Exception $e) {
    die("Failed to create database {$dbName}: {$e->getMessage()}");
}

// Run migrations for the isolated database
\Illuminate\Support\Facades\Artisan::call('migrate', [
    '--force' => true, // Skip confirmation in test environments
]);

2. Assign Unique Ports to Each App Instance #

Each parallel Dusk test needs its own app server port to avoid conflicts. Modify your DuskTestCase.php to start the server on a port based on the PARALLEL_TEST_TOKEN:

<?php

namespace Tests\Browser;

use Laravel\Dusk\TestCase as BaseTestCase;
use Facebook\WebDriver\Chrome\ChromeOptions;
use Facebook\WebDriver\Remote\RemoteWebDriver;
use Facebook\WebDriver\Remote\DesiredCapabilities;

abstract class DuskTestCase extends BaseTestCase
{
    use CreatesApplication;

    protected function baseUrl()
    {
        $token = getenv('PARALLEL_TEST_TOKEN') ?: 0;
        return "http://app:800{$token}"; // Match your Docker app service name
    }

    protected function startServer()
    {
        if (!static::$serverStarted) {
            $token = getenv('PARALLEL_TEST_TOKEN') ?: 0;
            $port = 8000 + (int)$token;
            static::startArtisanServer($port);
            static::$serverStarted = true;
        }
    }

    // Rest of your existing DuskTestCase code...
}

3. Run the Parallel Tests with the Correct Command #

Make sure you specify the Dusk PHPUnit config file in your Paratest command—this ensures all our isolation settings are used:

docker-compose exec app vendor/bin/paratest -p4 -c phpunit.dusk.xml tests/Browser/

Key Notes to Avoid Issues #

• Database Permissions: Ensure your database user has permission to create new databases. For MySQL in Docker, grant this with GRANT CREATE ON *.* TO 'your_user'@'%';.
• Docker Network Access: If using the Laravel Dusk Chrome container, confirm it's in the same Docker network as your app container—this lets Chrome reach your app's server via the http://app:{port} URL.
• Port Availability: Ensure ports 8000-8003 aren't occupied in your app container.
• Cleanup (Optional): Add a cleanup step to your bootstrap script or create an Artisan command to drop test databases after runs if needed.

内容的提问来源于stack exchange，提问作者Alexander Lyashov