diff --git a/manifest.xml b/manifest.xml
index fd731fb..f497780 100644
--- a/manifest.xml
+++ b/manifest.xml
@@ -8,6 +8,7 @@
 	<requires>
 		<php version="^7.1 || ^8.0">
 			<ext name="json"/>
+			<ext name="tokenizer"/>
 		</php>
 	</requires>
 </phar>
diff --git a/tests/Integration/ManifestTest.php b/tests/Integration/ManifestTest.php
index 46c0830..de9c762 100644
--- a/tests/Integration/ManifestTest.php
+++ b/tests/Integration/ManifestTest.php
@@ -5,24 +5,103 @@
 namespace Churn\Tests\Integration;
 
 use Churn\Tests\BaseTestCase;
+use PharIo\Manifest\Manifest;
 use PharIo\Manifest\ManifestLoader;
+use PharIo\Manifest\PhpExtensionRequirement;
+use RuntimeException;
 
 class ManifestTest extends BaseTestCase
 {
-    /** @test */
-    public function manifest_is_valid(): void
+    /** @var Manifest */
+    private $manifest;
+
+    /** @return void */
+    public function setUp()
     {
+        parent::setUp();
+
         $path = __DIR__ . '/../../manifest.xml';
         self::assertTrue(is_file($path), 'manifest.xml not found');
 
-        $manifest = ManifestLoader::fromFile($path);
+        $this->manifest = ManifestLoader::fromFile($path);
+    }
 
-        /**
-         * @psalm-suppress InvalidCast
-         * @phpstan-ignore-next-line
-         */
-        $name = method_exists($manifest->getName(), 'asString') ? $manifest->getName()->asString() : (string) $manifest->getName();
+    /** @test */
+    public function manifest_is_valid(): void
+    {
+        $name = $this->getStringRepresentation($this->manifest->getName());
         self::assertSame('bmitch/churn-php', $name);
-        self::assertGreaterThan(0, $manifest->getRequirements()->count());
+        self::assertGreaterThan(0, $this->manifest->getRequirements()->count());
+    }
+
+    /** @test */
+    public function manifest_requires_same_extensions_than_composer(): void
+    {
+        self::assertEqualsCanonicalizing(
+            $this->getComposerExtensionRequirements(),
+            $this->getManifestExtensionRequirements()
+        );
+    }
+
+    /**
+     * @return array<string>
+     */
+    private function getManifestExtensionRequirements(): array
+    {
+        $requirements = [];
+        foreach ($this->manifest->getRequirements() as $requirement) {
+            if (!$requirement instanceof PhpExtensionRequirement) {
+                continue;
+            }
+
+            $requirements[] = $this->getStringRepresentation($requirement);
+        }
+
+        return $requirements;
+    }
+
+    /**
+     * @return array<string>
+     */
+    private function getComposerExtensionRequirements(): array
+    {
+        $path = __DIR__ . '/../../composer.json';
+        self::assertNotFalse($contents = file_get_contents($path));
+        /** @var mixed $json */
+        $json = json_decode($contents, true);
+        self::assertIsArray($json);
+        self::assertArrayHasKey('require', $json);
+        self::assertIsArray($json['require']);
+
+        $requirements = [];
+        foreach (array_keys($json['require']) as $requirement) {
+            if (!is_string($requirement) || strpos($requirement, 'ext-') !== 0) {
+                continue;
+            }
+
+            $requirements[] = substr($requirement, 4);
+        }
+
+        return $requirements;
+    }
+
+    /**
+     * @param object $object
+     */
+    private function getStringRepresentation($object): string
+    {
+        $result = null;
+        if (method_exists($object, 'asString')) {
+            /** @var mixed $result */
+            $result = $object->asString();
+        } elseif (method_exists($object, '__toString')) {
+            /** @var mixed $result */
+            $result = $object->__toString();
+        }
+        if (!is_string($result)) {
+            throw new RuntimeException('String representation not found');
+        }
+
+        return $result;
     }
 }