diff --git a/composer.json b/composer.json
index 4631cb0..b603d54 100644
--- a/composer.json
+++ b/composer.json
@@ -70,7 +70,8 @@
     },
     "autoload-dev": {
         "psr-4": {
-            "App\\Tests\\": "tests/"
+            "App\\Tests\\": "tests/",
+            "Codeception\\Module\\Symfony\\": "tests/Support/Codeception/Module/Symfony/"
         }
     },
     "replace": {
diff --git a/composer.lock b/composer.lock
index 7cc8603..b82eaa6 100644
--- a/composer.lock
+++ b/composer.lock
@@ -5682,12 +5682,12 @@
             "source": {
                 "type": "git",
                 "url": "https://github.com/Codeception/module-symfony.git",
-                "reference": "784f1b034ba70686b1ac766c2664f1b1f2b1d638"
+                "reference": "a516dc6fc04db11d9d65f8de36297babf8fc16de"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/Codeception/module-symfony/zipball/784f1b034ba70686b1ac766c2664f1b1f2b1d638",
-                "reference": "784f1b034ba70686b1ac766c2664f1b1f2b1d638",
+                "url": "https://api.github.com/repos/Codeception/module-symfony/zipball/a516dc6fc04db11d9d65f8de36297babf8fc16de",
+                "reference": "a516dc6fc04db11d9d65f8de36297babf8fc16de",
                 "shasum": ""
             },
             "require": {
@@ -5699,35 +5699,37 @@
             "require-dev": {
                 "codeception/module-asserts": "^3.0",
                 "codeception/module-doctrine": "^3.1",
-                "doctrine/orm": "^2.20",
-                "symfony/browser-kit": "^5.4 | ^6.4 | ^7.2",
-                "symfony/cache": "^5.4 | ^6.4 | ^7.2",
-                "symfony/config": "^5.4 | ^6.4 | ^7.2",
-                "symfony/dependency-injection": "^5.4 | ^6.4 | ^7.2",
-                "symfony/dom-crawler": "^5.4 | ^6.4 | ^7.2",
-                "symfony/dotenv": "^5.4 | ^6.4 | ^7.2",
-                "symfony/error-handler": "^5.4 | ^6.4 | ^7.2",
-                "symfony/filesystem": "^5.4 | ^6.4 | ^7.2",
-                "symfony/form": "^5.4 | ^6.4 | ^7.2",
-                "symfony/framework-bundle": "^5.4 | ^6.4 | ^7.2",
-                "symfony/http-client": "^5.4 | ^6.4 | ^7.2",
-                "symfony/http-foundation": "^5.4 | ^6.4 | ^7.2",
-                "symfony/http-kernel": "^5.4 | ^6.4 | ^7.2",
-                "symfony/mailer": "^5.4 | ^6.4 | ^7.2",
-                "symfony/mime": "^5.4 | ^6.4 | ^7.2",
-                "symfony/notifier": "^5.4 | ^6.4 | ^7.2",
-                "symfony/options-resolver": "^5.4 | ^6.4 | ^7.2",
-                "symfony/property-access": "^5.4 | ^6.4 | ^7.2",
-                "symfony/property-info": "^5.4 | ^6.4 | ^7.2",
-                "symfony/routing": "^5.4 | ^6.4 | ^7.2",
-                "symfony/security-bundle": "^5.4 | ^6.4 | ^7.2",
-                "symfony/security-core": "^5.4 | ^6.4 | ^7.2",
-                "symfony/security-csrf": "^5.4 | ^6.4 | ^7.2",
-                "symfony/security-http": "^5.4 | ^6.4 | ^7.2",
-                "symfony/translation": "^5.4 | ^6.4 | ^7.2",
-                "symfony/twig-bundle": "^5.4 | ^6.4 | ^7.2",
-                "symfony/validator": "^5.4 | ^6.4 | ^7.2",
-                "symfony/var-exporter": "^5.4 | ^6.4 | ^7.2",
+                "doctrine/orm": "^3.5",
+                "friendsofphp/php-cs-fixer": "^3.85",
+                "phpstan/phpstan": "^2.1",
+                "symfony/browser-kit": "^5.4 | ^6.4 | ^7.3",
+                "symfony/cache": "^5.4 | ^6.4 | ^7.3",
+                "symfony/config": "^5.4 | ^6.4 | ^7.3",
+                "symfony/dependency-injection": "^5.4 | ^6.4 | ^7.3",
+                "symfony/dom-crawler": "^5.4 | ^6.4 | ^7.3",
+                "symfony/dotenv": "^5.4 | ^6.4 | ^7.3",
+                "symfony/error-handler": "^5.4 | ^6.4 | ^7.3",
+                "symfony/filesystem": "^5.4 | ^6.4 | ^7.3",
+                "symfony/form": "^5.4 | ^6.4 | ^7.3",
+                "symfony/framework-bundle": "^5.4 | ^6.4 | ^7.3",
+                "symfony/http-client": "^5.4 | ^6.4 | ^7.3",
+                "symfony/http-foundation": "^5.4 | ^6.4 | ^7.3",
+                "symfony/http-kernel": "^5.4 | ^6.4 | ^7.3",
+                "symfony/mailer": "^5.4 | ^6.4 | ^7.3",
+                "symfony/mime": "^5.4 | ^6.4 | ^7.3",
+                "symfony/notifier": "^5.4 | ^6.4 | ^7.3",
+                "symfony/options-resolver": "^5.4 | ^6.4 | ^7.3",
+                "symfony/property-access": "^5.4 | ^6.4 | ^7.3",
+                "symfony/property-info": "^5.4 | ^6.4 | ^7.3",
+                "symfony/routing": "^5.4 | ^6.4 | ^7.3",
+                "symfony/security-bundle": "^5.4 | ^6.4 | ^7.3",
+                "symfony/security-core": "^5.4 | ^6.4 | ^7.3",
+                "symfony/security-csrf": "^5.4 | ^6.4 | ^7.3",
+                "symfony/security-http": "^5.4 | ^6.4 | ^7.3",
+                "symfony/translation": "^5.4 | ^6.4 | ^7.3",
+                "symfony/twig-bundle": "^5.4 | ^6.4 | ^7.3",
+                "symfony/validator": "^5.4 | ^6.4 | ^7.3",
+                "symfony/var-exporter": "^5.4 | ^6.4 | ^7.3",
                 "vlucas/phpdotenv": "^4.2 | ^5.4"
             },
             "suggest": {
@@ -5737,9 +5739,9 @@
             "default-branch": true,
             "type": "library",
             "autoload": {
-                "classmap": [
-                    "src/"
-                ]
+                "psr-4": {
+                    "Codeception\\": "src/Codeception/"
+                }
             },
             "notification-url": "https://packagist.org/downloads/",
             "license": [
@@ -5766,7 +5768,7 @@
                 "issues": "https://github.com/Codeception/module-symfony/issues",
                 "source": "https://github.com/Codeception/module-symfony/tree/main"
             },
-            "time": "2025-08-03T21:05:47+00:00"
+            "time": "2025-08-09T19:27:12+00:00"
         },
         {
             "name": "codeception/stub",
@@ -6453,16 +6455,16 @@
         },
         {
             "name": "doctrine/orm",
-            "version": "3.5.1",
+            "version": "3.5.2",
             "source": {
                 "type": "git",
                 "url": "https://github.com/doctrine/orm.git",
-                "reference": "64444dcfd511089d526cd2c7f74b9d7ed583bdfc"
+                "reference": "5a541b8b3a327ab1ea5f93b1615b4ff67a34e109"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/doctrine/orm/zipball/64444dcfd511089d526cd2c7f74b9d7ed583bdfc",
-                "reference": "64444dcfd511089d526cd2c7f74b9d7ed583bdfc",
+                "url": "https://api.github.com/repos/doctrine/orm/zipball/5a541b8b3a327ab1ea5f93b1615b4ff67a34e109",
+                "reference": "5a541b8b3a327ab1ea5f93b1615b4ff67a34e109",
                 "shasum": ""
             },
             "require": {
@@ -6537,9 +6539,9 @@
             ],
             "support": {
                 "issues": "https://github.com/doctrine/orm/issues",
-                "source": "https://github.com/doctrine/orm/tree/3.5.1"
+                "source": "https://github.com/doctrine/orm/tree/3.5.2"
             },
-            "time": "2025-08-05T06:05:51+00:00"
+            "time": "2025-08-08T17:00:40+00:00"
         },
         {
             "name": "evenement/evenement",
@@ -8093,16 +8095,16 @@
         },
         {
             "name": "phpunit/phpunit",
-            "version": "10.5.48",
+            "version": "10.5.49",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/phpunit.git",
-                "reference": "6e0a2bc39f6fae7617989d690d76c48e6d2eb541"
+                "reference": "e2571b0e6e372de90f0b147b0cb9379bb105c124"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/6e0a2bc39f6fae7617989d690d76c48e6d2eb541",
-                "reference": "6e0a2bc39f6fae7617989d690d76c48e6d2eb541",
+                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/e2571b0e6e372de90f0b147b0cb9379bb105c124",
+                "reference": "e2571b0e6e372de90f0b147b0cb9379bb105c124",
                 "shasum": ""
             },
             "require": {
@@ -8112,7 +8114,7 @@
                 "ext-mbstring": "*",
                 "ext-xml": "*",
                 "ext-xmlwriter": "*",
-                "myclabs/deep-copy": "^1.13.3",
+                "myclabs/deep-copy": "^1.13.4",
                 "phar-io/manifest": "^2.0.4",
                 "phar-io/version": "^3.2.1",
                 "php": ">=8.1",
@@ -8174,7 +8176,7 @@
             "support": {
                 "issues": "https://github.com/sebastianbergmann/phpunit/issues",
                 "security": "https://github.com/sebastianbergmann/phpunit/security/policy",
-                "source": "https://github.com/sebastianbergmann/phpunit/tree/10.5.48"
+                "source": "https://github.com/sebastianbergmann/phpunit/tree/10.5.49"
             },
             "funding": [
                 {
@@ -8198,7 +8200,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2025-07-11T04:07:17+00:00"
+            "time": "2025-08-09T07:08:00+00:00"
         },
         {
             "name": "psr/http-client",
diff --git a/tests/Functional.suite.yml b/tests/Functional.suite.yml
index 9867a88..6632bec 100644
--- a/tests/Functional.suite.yml
+++ b/tests/Functional.suite.yml
@@ -9,3 +9,4 @@ modules:
         - Doctrine:
               depends: Symfony
               cleanup: true
+        - App\Tests\Support\Helper\Environment
diff --git a/tests/Functional/EnvironmentAssertionsCest.php b/tests/Functional/EnvironmentAssertionsCest.php
new file mode 100644
index 0000000..d2992e1
--- /dev/null
+++ b/tests/Functional/EnvironmentAssertionsCest.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Functional;
+
+use App\Tests\Support\FunctionalTester;
+
+class EnvironmentAssertionsCest
+{
+    public function _before(): void
+    {
+        @mkdir(codecept_root_dir() . 'var/log', 0777, true);
+        @mkdir(codecept_root_dir() . 'var/sessions/test', 0777, true);
+    }
+
+    public function symfonyKernelAssertions(FunctionalTester $I): void
+    {
+        $I->assertKernelEnvironment('test');
+        $I->assertDebugModeIsEnabled();
+        $I->assertSymfonyVersion('>=', '7.3');
+        $I->assertAppEnvAndDebugMatchKernel();
+        $I->assertAppCacheIsWritable();
+        $I->assertProjectStructureIsSane();
+    }
+
+    public function serviceAndBundleAssertions(FunctionalTester $I): void
+    {
+        $I->assertBundleIsEnabled(\Symfony\Bundle\FrameworkBundle\FrameworkBundle::class);
+    }
+
+    public function securityAssertions(FunctionalTester $I): void
+    {
+        $I->assertFirewallIsActive('main');
+    }
+
+    public function doctrineAssertions(FunctionalTester $I): void
+    {
+        $I->assertDoctrineDatabaseIsUp();
+    }
+
+    public function otherComponentAssertions(FunctionalTester $I): void
+    {
+        $I->assertSessionSavePathIsWritable();
+        $I->assertKernelCharsetIs('UTF-8');
+    }
+}
diff --git a/tests/Support/Codeception/Module/Symfony/EnvironmentAssertionsTrait.php b/tests/Support/Codeception/Module/Symfony/EnvironmentAssertionsTrait.php
new file mode 100644
index 0000000..cdb88e0
--- /dev/null
+++ b/tests/Support/Codeception/Module/Symfony/EnvironmentAssertionsTrait.php
@@ -0,0 +1,536 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Codeception\Module\Symfony;
+
+use Codeception\Module\Symfony as SymfonyModule;
+use Doctrine\ORM\Tools\SchemaValidator;
+use Doctrine\Persistence\ManagerRegistry;
+use LogicException;
+use PHPUnit\Framework\Assert;
+use Symfony\Component\DependencyInjection\ParameterBag\ContainerBagInterface;
+use Symfony\Component\HttpKernel\Kernel;
+use Throwable;
+
+use function array_keys;
+use function date_default_timezone_get;
+use function file_exists;
+use function file_get_contents;
+use function get_class;
+use function getenv;
+use function implode;
+use function in_array;
+use function ini_get;
+use function is_array;
+use function is_dir;
+use function is_executable;
+use function is_file;
+use function is_readable;
+use function is_string;
+use function is_writable;
+use function method_exists;
+use function preg_match_all;
+use function sprintf;
+use function strtolower;
+use function version_compare;
+
+/**
+ * Provides comprehensive environment-related assertions for Symfony applications in Codeception.
+ *
+ * This trait validates the project's sanity, from PHP/Composer to high-level Symfony components.
+ * It aims to catch common configuration and environment issues early, especially in CI/CD pipelines.
+ *
+ * Recommended Usage: Create a dedicated test suite (e.g., 'environment') and a Cest file (e.g., EnvironmentCest)
+ * to run these checks once per deployment or test run, as some assertions can be time-consuming.
+ */
+trait EnvironmentAssertionsTrait
+{
+    // =========================================================================
+    // Symfony Application Health Assertions
+    // =========================================================================
+
+    /**
+     * Asserts that the Kernel is running in the expected environment (e.g., 'test', 'dev').
+     */
+    public function assertKernelEnvironment(string $expectedEnv): void
+    {
+        $currentEnv = $this->getKernel()->getEnvironment();
+        Assert::assertSame(
+            $expectedEnv,
+            $currentEnv,
+            sprintf('Kernel is running in environment "%s" but expected "%s".', $currentEnv, $expectedEnv)
+        );
+    }
+
+    /**
+     * Asserts that the application's debug mode is enabled.
+     */
+    public function assertDebugModeIsEnabled(): void
+    {
+        $isDebug = $this->getKernel()->isDebug();
+        Assert::assertTrue($isDebug, 'Debug mode is expected to be enabled, but it is not.');
+    }
+
+    /**
+     * Asserts that the application's debug mode is disabled (production-like).
+     */
+    public function assertDebugModeIsDisabled(): void
+    {
+        $isDebug = $this->getKernel()->isDebug();
+        Assert::assertFalse($isDebug, 'Debug mode is expected to be disabled, but it is enabled.');
+    }
+
+    /**
+     * Asserts that the current Symfony version satisfies the given comparison.
+     * Example: `$I->assertSymfonyVersion('>=', '6.4');`
+     */
+    public function assertSymfonyVersion(string $operator, string $version, string $message = ''): void
+    {
+        Assert::assertTrue(
+            version_compare(Kernel::VERSION, $version, $operator),
+            $message ?: sprintf('Symfony version %s does not satisfy the constraint: %s %s', Kernel::VERSION, $operator, $version)
+        );
+    }
+
+    /**
+     * Asserts that `APP_ENV` and `APP_DEBUG` env vars match the Kernel state.
+     */
+    public function assertAppEnvAndDebugMatchKernel(): void
+    {
+        $kernel = $this->getKernel();
+        $appEnv = getenv('APP_ENV');
+        $appDebug = getenv('APP_DEBUG');
+
+        if ($appEnv !== false) {
+            Assert::assertSame(
+                $kernel->getEnvironment(),
+                (string) $appEnv,
+                sprintf('APP_ENV (%s) differs from Kernel environment (%s).', $appEnv, $kernel->getEnvironment())
+            );
+        }
+
+        if ($appDebug !== false) {
+            $expected = $kernel->isDebug();
+            $normalized = in_array(strtolower((string) $appDebug), ['1', 'true', 'yes', 'on'], true);
+            Assert::assertSame(
+                $expected,
+                $normalized,
+                sprintf('APP_DEBUG (%s) differs from Kernel debug (%s).', $appDebug, $expected ? 'true' : 'false')
+            );
+        }
+    }
+
+    /**
+     * Asserts that the application's cache directory is writable.
+     */
+    public function assertAppCacheIsWritable(): void
+    {
+        $cacheDir = $this->getKernel()->getCacheDir();
+        Assert::assertTrue(
+            is_writable($cacheDir),
+            sprintf('Symfony cache directory is not writable: %s', $cacheDir)
+        );
+    }
+
+    /**
+     * Asserts that the application's log directory is writable (parameter-first).
+     */
+    public function assertAppLogIsWritable(): void
+    {
+        $container = $this->getSymfonyModule()->_getContainer();
+        $logDir = null;
+        if ($container->hasParameter('kernel.logs_dir')) {
+            $logDir = (string) $container->getParameter('kernel.logs_dir');
+        }
+
+        if (!$logDir) {
+            $logDir = method_exists($this->getKernel(), 'getLogDir')
+                ? $this->getKernel()->getLogDir()
+                : $this->getProjectDir() . 'var/log';
+        }
+
+        Assert::assertTrue(
+            is_writable($logDir),
+            sprintf('Symfony log directory is not writable: %s', $logDir)
+        );
+    }
+
+    /**
+     * Asserts that the minimal Symfony project structure exists and is usable.
+     */
+    public function assertProjectStructureIsSane(): void
+    {
+        $root = $this->getProjectDir();
+        foreach (['config', 'src', 'public', 'var'] as $dir) {
+            Assert::assertTrue(is_dir($root . $dir), sprintf('Directory "%s" is missing.', $dir));
+        }
+
+        foreach (['var/cache', 'var/log'] as $dir) {
+            Assert::assertTrue(is_dir($root . $dir), sprintf('Directory "%s" is missing.', $dir));
+            Assert::assertTrue(is_writable($root . $dir), sprintf('Directory "%s" is not writable.', $dir));
+        }
+
+        Assert::assertFileExists($root . 'config/bundles.php', 'Missing config/bundles.php file.');
+
+        $bin = $root . 'bin/console';
+        Assert::assertTrue(is_file($bin), 'bin/console is missing.');
+        if (strncasecmp(PHP_OS, 'WIN', 3) !== 0) {
+            Assert::assertTrue(is_executable($bin) || is_file($bin), 'bin/console is not executable.');
+        }
+    }
+
+    /**
+     * Asserts that all keys in example env file(s) exist either in the provided env file(s) OR as OS env vars.
+     * This validates presence only, not values. It also considers common local/test files if present.
+     *
+     * @param non-empty-string $envPath
+     * @param non-empty-string $examplePath
+     * @param list<non-empty-string> $additionalEnvPaths
+     */
+    public function assertEnvFileIsSynchronized(string $envPath = '.env', string $examplePath = '.env.example', array $additionalEnvPaths = []): void
+    {
+        $projectDir = $this->getProjectDir();
+
+        $candidateExtras = ['.env.local', '.env.test', '.env.test.local'];
+        foreach ($candidateExtras as $extra) {
+            if (file_exists($projectDir . $extra)) {
+                $additionalEnvPaths[] = $extra;
+            }
+        }
+
+        $exampleContent = @file_get_contents($projectDir . $examplePath) ?: '';
+        $envContent     = @file_get_contents($projectDir . $envPath) ?: '';
+
+        foreach ($additionalEnvPaths as $extra) {
+            $envContent .= "\n" . (@file_get_contents($projectDir . $extra) ?: '');
+        }
+
+        $exampleKeys = $this->extractEnvKeys($exampleContent);
+        $envKeys     = $this->extractEnvKeys($envContent);
+
+        $osKeys = array_keys($_ENV + $_SERVER);
+        $present = array_flip(array_merge($envKeys, $osKeys));
+
+        $missing = [];
+        foreach ($exampleKeys as $key) {
+            if (!isset($present[$key])) {
+                $missing[] = $key;
+            }
+        }
+
+        Assert::assertEmpty(
+            $missing,
+            sprintf('Missing variables from %s (not found across %s nor as OS envs): %s', $examplePath, implode(', ', array_merge([$envPath], $additionalEnvPaths)), implode(', ', $missing))
+        );
+    }
+
+    // =========================================================================
+    // Symfony Components & Services Assertions
+    // =========================================================================
+
+    /**
+     * Asserts that a specific bundle is enabled in the Kernel.
+     * @param class-string $bundleClass The Fully Qualified Class Name of the bundle.
+     */
+    public function assertBundleIsEnabled(string $bundleClass): void
+    {
+        $bundles = $this->getKernel()->getBundles();
+        $found = false;
+        foreach ($bundles as $bundle) {
+            if ($bundle instanceof $bundleClass || get_class($bundle) === $bundleClass) {
+                $found = true;
+                break;
+            }
+        }
+
+        Assert::assertTrue(
+            $found,
+            sprintf('Bundle "%s" is not enabled in the Kernel. Check config/bundles.php.', $bundleClass)
+        );
+    }
+
+    // =========================================================================
+    // Security Assertions
+    // =========================================================================
+
+    /**
+     * Asserts that a security firewall is active (configured).
+     */
+    public function assertFirewallIsActive(string $firewallName): void
+    {
+        $container = $this->getSymfonyModule()->_getContainer();
+
+        if ($container->hasParameter('security.firewalls')) {
+            /** @var list<string> $firewalls */
+            $firewalls = $container->getParameter('security.firewalls');
+            Assert::assertContains($firewallName, $firewalls, sprintf('Firewall "%s" is not configured. Check your security.yaml.', $firewallName));
+            return;
+        }
+
+        $contextId = 'security.firewall.map.context.' . $firewallName;
+        Assert::assertTrue(
+            $container->has($contextId),
+            sprintf('Firewall "%s" context was not found (checked "%s").', $firewallName, $contextId)
+        );
+    }
+
+    /**
+     * Asserts that a role is present either as a key of the role hierarchy or among any inherited roles.
+     * Skips when role hierarchy is not configured.
+     */
+    public function assertRoleInHierarchy(string $role): void
+    {
+        $container = $this->getSymfonyModule()->_getContainer();
+        if (!$container->hasParameter('security.role_hierarchy.roles')) {
+            Assert::markTestSkipped('Role hierarchy is not configured; skipping role hierarchy assertion.');
+        }
+
+        /** @var array<string, list<string>> $hierarchy */
+        $hierarchy = $container->getParameter('security.role_hierarchy.roles');
+
+        $all = array_keys($hierarchy);
+        foreach ($hierarchy as $children) {
+            foreach ($children as $child) {
+                $all[] = $child;
+            }
+        }
+        $all = array_values(array_unique($all));
+        Assert::assertContains(
+            $role,
+            $all,
+            sprintf('Role "%s" was not found in the role hierarchy. Check security.yaml.', $role)
+        );
+    }
+
+    /**
+     * Asserts that a secret from the Symfony vault can be resolved.
+     * @param non-empty-string $secretName The name of the secret (e.g., 'DATABASE_PASSWORD').
+     */
+    public function assertCanResolveSecret(string $secretName): void
+    {
+        try {
+            /** @var ContainerBagInterface $params */
+            $params = $this->grabService('parameter_bag');
+            $value = $params->get(sprintf('env(resolve:%s)', $secretName));
+
+            Assert::assertIsString($value, sprintf('Secret "%s" could be resolved but did not return a string.', $secretName));
+        } catch (Throwable $e) {
+            Assert::fail(sprintf('Failed to resolve secret "%s". Check your vault and decryption keys. Error: %s', $secretName, $e->getMessage()));
+        }
+    }
+
+    // =========================================================================
+    // Doctrine Assertions
+    // =========================================================================
+
+    /**
+     * Asserts that the application can connect to a Doctrine database.
+     * @param non-empty-string $connectionName The name of the Doctrine connection to check.
+     */
+    public function assertDoctrineDatabaseIsUp(string $connectionName = 'default'): void
+    {
+        try {
+            /** @var ManagerRegistry $doctrine */
+            $doctrine = $this->grabService('doctrine');
+            $connection = $doctrine->getConnection($connectionName);
+            $connection->executeQuery($connection->getDatabasePlatform()->getDummySelectSQL());
+            Assert::assertTrue(true, sprintf('Doctrine connection "%s" is up and responsive.', $connectionName));
+        } catch (Throwable $e) {
+            Assert::fail(sprintf('Doctrine connection "%s" failed: %s', $connectionName, $e->getMessage()));
+        }
+    }
+
+    /**
+     * Asserts that the Doctrine mapping is valid and the DB schema is in sync for one EM.
+     * Programmatic equivalent of `bin/console doctrine:schema:validate`.
+     * @param non-empty-string $entityManagerName
+     */
+    public function assertDoctrineSchemaIsValid(string $entityManagerName = 'default'): void
+    {
+        try {
+            /** @var ManagerRegistry $doctrine */
+            $doctrine = $this->grabService('doctrine');
+            $em = $doctrine->getManager($entityManagerName);
+            $validator = new SchemaValidator($em);
+            $errors = $validator->validateMapping();
+            $errorMessages = [];
+            foreach ($errors as $className => $classErrors) {
+                $errorMessages[] = sprintf(' - %s: %s', $className, implode('; ', $classErrors));
+            }
+            Assert::assertEmpty(
+                $errors,
+                sprintf(
+                    "The Doctrine mapping is invalid for the '%s' entity manager:\n%s",
+                    $entityManagerName,
+                    implode("\n", $errorMessages)
+                )
+            );
+
+            if (!$validator->schemaInSyncWithMetadata()) {
+                Assert::fail(sprintf(
+                    'The database schema is not in sync with the current mapping for the "%s" entity manager. Generate and run a new migration.',
+                    $entityManagerName
+                ));
+            }
+            Assert::assertTrue(true, sprintf('Doctrine schema for "%s" EM is valid and synchronized.', $entityManagerName));
+        } catch (Throwable $e) {
+            Assert::fail(sprintf('Could not validate Doctrine schema for the "%s" entity manager: %s', $entityManagerName, $e->getMessage()));
+        }
+    }
+
+    /**
+     * Asserts that Doctrine proxy directory is writable for a given EM.
+     */
+    public function assertDoctrineProxyDirIsWritable(string $entityManagerName = 'default'): void
+    {
+        /** @var ManagerRegistry $doctrine */
+        $doctrine = $this->grabService('doctrine');
+        $em = $doctrine->getManager($entityManagerName);
+        $proxyDir = $em->getConfiguration()->getProxyDir();
+        Assert::assertTrue($proxyDir !== null && $proxyDir !== '', sprintf('Doctrine proxy dir is not configured for EM "%s".', $entityManagerName));
+        Assert::assertTrue(is_dir($proxyDir), sprintf('Doctrine proxy dir does not exist: %s', $proxyDir));
+        Assert::assertTrue(is_writable($proxyDir), sprintf('Doctrine proxy dir is not writable: %s', $proxyDir));
+    }
+
+    // =========================================================================
+    // Other Component Assertions
+    // =========================================================================
+
+    /**
+     * Asserts that an asset manifest file exists, checking for Webpack Encore or AssetMapper.
+     * A common CI/CD failure point is missing frontend assets.
+     */
+    public function assertAssetManifestExists(): void
+    {
+        $projectDir = $this->getProjectDir();
+        $encoreManifest = $projectDir . 'public/build/manifest.json';
+        $mapperManifest = $projectDir . 'public/assets/manifest.json';
+        $encoreEntrypoints = $projectDir . 'public/build/entrypoints.json';
+
+        if (is_readable($encoreManifest) && is_readable($encoreEntrypoints)) {
+            Assert::assertJson((string) file_get_contents($encoreManifest), 'Webpack Encore manifest.json is not valid JSON.');
+            Assert::assertJson((string) file_get_contents($encoreEntrypoints), 'Webpack Encore entrypoints.json is not valid JSON.');
+            Assert::assertTrue(true, 'Webpack Encore manifest files found and are valid.');
+            return;
+        }
+
+        if (is_readable($mapperManifest)) {
+            Assert::assertJson((string) file_get_contents($mapperManifest), 'AssetMapper manifest.json is not valid JSON.');
+            Assert::assertTrue(true, 'AssetMapper manifest file found and is valid.');
+            return;
+        }
+
+        Assert::fail('No asset manifest file found. Checked for Webpack Encore (public/build/manifest.json) and AssetMapper (public/assets/manifest.json).');
+    }
+
+    /**
+     * Asserts that the session save path is writable when using file-based sessions.
+     * Skips when session storage is not file-based.
+     */
+    public function assertSessionSavePathIsWritable(): void
+    {
+        $container = $this->getSymfonyModule()->_getContainer();
+
+        $isFileBased = false;
+        if ($container->has('session.storage.factory.native_file') || $container->has('session.handler.native_file')) {
+            $isFileBased = true;
+        }
+        $iniHandler = (string) (ini_get('session.save_handler') ?: '');
+        if ($iniHandler === 'files') {
+            $isFileBased = true;
+        }
+
+        if (!$isFileBased) {
+            Assert::markTestSkipped('Session storage is not file-based; skipping save path writability check.');
+        }
+
+        $savePath = null;
+
+        if ($container->hasParameter('session.storage.options')) {
+            $options = $container->getParameter('session.storage.options');
+            if (is_array($options) && isset($options['save_path']) && is_string($options['save_path']) && $options['save_path'] !== '') {
+                $savePath = $options['save_path'];
+            }
+        }
+
+        if (!$savePath) {
+            $ini = (string) (ini_get('session.save_path') ?: '');
+            if ($ini !== '') {
+                $savePath = $ini;
+            }
+        }
+
+        if (!$savePath) {
+            $env = $this->getKernel()->getEnvironment();
+            $savePath = $this->getProjectDir() . 'var/sessions/' . $env;
+        }
+
+        Assert::assertTrue(is_dir($savePath), sprintf('Session save path is not a directory: %s', $savePath));
+        Assert::assertTrue(is_writable($savePath), sprintf('Session save path is not writable: %s', $savePath));
+    }
+
+    /**
+     * Asserts the Kernel charset matches the expected value.
+     */
+    public function assertKernelCharsetIs(string $expected = 'UTF-8'): void
+    {
+        $charset = $this->getKernel()->getCharset();
+        Assert::assertSame($expected, $charset, sprintf('Kernel charset is "%s" but expected "%s".', $charset, $expected));
+    }
+
+    // =========================================================================
+    // Trait Internals
+    // =========================================================================
+
+    /**
+     * Helper to get the Symfony module.
+     */
+    private function getSymfonyModule(): SymfonyModule
+    {
+        $symfonyModule = $this->getModule('Symfony');
+        if (!$symfonyModule instanceof SymfonyModule) {
+            throw new LogicException('This trait can only be used in a class that uses the Codeception Symfony module.');
+        }
+        return $symfonyModule;
+    }
+
+    /**
+     * Helper to get a service from the container.
+     */
+    private function grabService(string $serviceId): object
+    {
+        return $this->getSymfonyModule()->_getContainer()->get($serviceId);
+    }
+
+    /**
+     * Helper to get the Kernel instance.
+     */
+    private function getKernel(): Kernel
+    {
+        /** @var Kernel $kernel */
+        $kernel = $this->getSymfonyModule()->grabService('kernel');
+        return $kernel;
+    }
+
+    /**
+     * Helper to get the project's root directory.
+     */
+    private function getProjectDir(): string
+    {
+        return $this->getKernel()->getProjectDir() . '/';
+    }
+
+    /**
+     * Extracts variable keys from the content of a .env file.
+     * @return list<string>
+     */
+    private function extractEnvKeys(string $content): array
+    {
+        $keys = [];
+        if (preg_match_all('/^(?!#)\s*([a-zA-Z_][a-zA-Z0-9_]*)=/m', $content, $matches)) {
+            $keys = $matches[1];
+        }
+        return $keys;
+    }
+}
diff --git a/tests/Support/Helper/Environment.php b/tests/Support/Helper/Environment.php
new file mode 100644
index 0000000..a803895
--- /dev/null
+++ b/tests/Support/Helper/Environment.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Support\Helper;
+
+use Codeception\Module;
+use Codeception\Module\Symfony\EnvironmentAssertionsTrait;
+
+class Environment extends Module
+{
+    use EnvironmentAssertionsTrait;
+}