Let the user build its own randomizer engine to fix the seed and get reproductible results.

src/Container/Container.php

@@ -3,6 +3,7 @@
 namespace Xefi\Faker\Container;
 
 use Closure;
+use Random\Engine;
 use Xefi\Faker\Container\Traits\HasExtensions;
 use Xefi\Faker\Container\Traits\HasLocale;
 use Xefi\Faker\Container\Traits\HasModifiers;
@@ -47,13 +48,20 @@ class Container
      */
     protected static string $containerMixinManifestPath = './faker_mixin.php';
 
+    /**
+     * @var Engine|null
+     */
+    private ?Engine $engine;
+
     /**
      * Create the container instance.
      *
      * @return void
      */
-    public function __construct(bool $shouldBuildContainerMixin = true)
+    public function __construct(?Engine $engine = null, bool $shouldBuildContainerMixin = true)
     {
+        $this->engine = $engine;
+
         if (!$this->areExtensionsInitialized()) {
             $this->registerConfiguredProviders();
 
@@ -101,6 +109,14 @@ public static function basePath(string $basePath)
         static::$basePath = $basePath;
     }
 
+    /**
+     * @return Engine|null
+     */
+    public function getEngine(): ?Engine
+    {
+        return $this->engine;
+    }
+
     /**
      * Build container mixin manifest.
      */

src/Container/Traits/HasExtensions.php

@@ -2,6 +2,7 @@
 
 namespace Xefi\Faker\Container\Traits;
 
+use Random\Engine;
 use Random\Randomizer;
 use Xefi\Faker\Container\Container;
 use Xefi\Faker\Container\Enum\Locales;
@@ -27,14 +28,15 @@ trait HasExtensions
     /**
      * Resolve an array of extensions through the container.
      *
-     * @param array $extensions
+     * @param array       $extensions
+     * @param Engine|null $engine
      *
      * @return $this
      */
-    public function resolveExtensions(array $extensions): self
+    public function resolveExtensions(array $extensions, ?Engine $engine = null): self
     {
         foreach ($extensions as $extension) {
-            $this->resolve($extension);
+            $this->resolve($extension, $engine);
         }
 
         return $this;
@@ -44,12 +46,13 @@ public function resolveExtensions(array $extensions): self
      * Add an extension, resolving through the application.
      *
      * @param Extension|string $extension
+     * @param Engine|null      $engine
      *
      * @return Container
      */
-    protected function resolve(\Xefi\Faker\Extensions\Extension|string $extension): Container
+    protected function resolve(\Xefi\Faker\Extensions\Extension|string $extension, ?Engine $engine = null): Container
     {
-        $instance = $extension instanceof Extension ? $extension : new $extension(new Randomizer());
+        $instance = $extension instanceof Extension ? $extension : new $extension(new Randomizer($engine));
 
         // If the extension supports locale variations
         if (method_exists($instance, 'getLocale')) {

src/Container/Traits/HasModifiers.php

@@ -27,7 +27,7 @@ trait HasModifiers
      */
     public function nullable(int $weight = 50): self
     {
-        $this->modifiers[] = new NullableModifier(new Randomizer(), $weight);
+        $this->modifiers[] = new NullableModifier(new Randomizer($this->engine), $weight);
 
         return $this;
     }

src/Extensions/Extension.php

@@ -9,7 +9,7 @@ class Extension
 {
     protected Randomizer $randomizer;
 
-    public function __construct(Randomizer $randomizer)
+    final public function __construct(Randomizer $randomizer)
     {
         $this->randomizer = $randomizer;
     }

src/Faker.php

@@ -2,6 +2,7 @@
 
 namespace Xefi\Faker;
 
+use Random\Engine;
 use Xefi\Faker\Container\Container;
 
 /**
@@ -16,14 +17,22 @@ class Faker
      */
     protected ?string $locale;
 
-    public function __construct(?string $locale = null)
+    /**
+     * The current Randomizer engine.
+     *
+     * @var Engine|null
+     */
+    protected ?Engine $engine;
+
+    public function __construct(?string $locale = null, ?Engine $engine = null)
     {
         $this->locale = $locale;
+        $this->engine = $engine;
     }
 
     public function __call(string $method, array $parameters)
     {
         // We simply redirect calls to container to create a new container for each faker call
-        return (new Container())->locale($this->locale)->{$method}(...$parameters);
+        return (new Container($this->engine))->locale($this->locale)->{$method}(...$parameters);
     }
 }

src/Providers/Provider.php

@@ -16,7 +16,7 @@ class Provider
     public function extensions(array $extensions)
     {
         Container::starting(function (Container $container) use ($extensions) {
-            $container->resolveExtensions($extensions);
+            $container->resolveExtensions($extensions, $container->getEngine());
         });
     }
 

tests/Support/Extensions/NumberTestExtension.php

@@ -13,6 +13,6 @@ public function returnOne()
 
     public function returnNumberBetween($min, $max)
     {
-        return rand($min, $max);
+        return $this->randomizer->getInt($min, $max);
     }
 }

tests/Unit/Extensions/HashExtensionTest.php

@@ -11,24 +11,56 @@ public function testSha1(): void
         $this->assertMatchesRegularExpression('/^[a-z0-9]{40}$/', $result);
     }
 
+    public function testSha1IsSeedable(): void
+    {
+        $this->assertEquals(
+            $this->createFresh()->sha1(),
+            $this->createFresh()->sha1(),
+        );
+    }
+
     public function testSha256(): void
     {
         $result = $this->faker->sha256();
 
         $this->assertMatchesRegularExpression('/^[a-z0-9]{64}$/', $result);
     }
 
+    public function testSha256IsSeedable(): void
+    {
+        $this->assertEquals(
+            $this->createFresh()->sha256(),
+            $this->createFresh()->sha256(),
+        );
+    }
+
     public function testSha512(): void
     {
         $result = $this->faker->sha512();
 
         $this->assertMatchesRegularExpression('/^[a-z0-9]{128}$/', $result);
     }
 
+    public function testSha512IsSeedable(): void
+    {
+        $this->assertEquals(
+            $this->createFresh()->sha512(),
+            $this->createFresh()->sha512(),
+        );
+    }
+
     public function testMd5(): void
     {
         $result = $this->faker->md5();
 
         $this->assertMatchesRegularExpression('/^[a-fA-F0-9]{32}$/', $result);
     }
+
+    public function testMd5IsSeedable(): void
+    {
+        $this->assertEquals(
+            $this->createFresh()->md5(),
+            $this->createFresh()->md5(),
+        );
+    }
 }

tests/Unit/Extensions/InternetExtensionTest.php

@@ -19,7 +19,7 @@ protected function setUp(): void
 
     public function testSdl(): void
     {
-        $faker = new Container(false);
+        $faker = new Container(null, false);
 
         $results = [];
 
@@ -34,7 +34,7 @@ public function testSdl(): void
 
     public function testTld(): void
     {
-        $faker = new Container(false);
+        $faker = new Container(null, false);
 
         $results = [];
 
@@ -47,7 +47,7 @@ public function testTld(): void
 
     public function testDomain(): void
     {
-        $faker = new Container(false);
+        $faker = new Container(null, false);
 
         $results = [];
 
@@ -62,7 +62,7 @@ public function testDomain(): void
 
     public function testIp(): void
     {
-        $faker = new Container(false);
+        $faker = new Container(null, false);
 
         for ($i = 0; $i < 50; $i++) {
             $result = $faker->ip();
@@ -73,7 +73,7 @@ public function testIp(): void
 
     public function testIpv4(): void
     {
-        $faker = new Container(false);
+        $faker = new Container(null, false);
 
         $results = [];
 
@@ -88,7 +88,7 @@ public function testIpv4(): void
 
     public function testIpv6(): void
     {
-        $faker = new Container(false);
+        $faker = new Container(null, false);
 
         $results = [];
 
@@ -103,7 +103,7 @@ public function testIpv6(): void
 
     public function testMacAddress(): void
     {
-        $faker = new Container(false);
+        $faker = new Container(null, false);
 
         $results = [];
 
@@ -118,7 +118,7 @@ public function testMacAddress(): void
 
     public function testEmail(): void
     {
-        $faker = new Container(false);
+        $faker = new Container(null, false);
 
         $results = [];
 

tests/Unit/Extensions/TestCase.php

@@ -2,6 +2,7 @@
 
 namespace Xefi\Faker\Tests\Unit\Extensions;
 
+use Random\Engine\Mt19937;
 use Xefi\Faker\Container\Container;
 use Xefi\Faker\FakerServiceProvider;
 
@@ -15,6 +16,18 @@ protected function setUp(): void
 
         (new FakerServiceProvider())->boot();
 
-        $this->faker = new Container(false);
+        $this->faker = new Container(new Mt19937(19937), false);
+    }
+
+    protected function createFresh(): Container
+    {
+        $this->faker->forgetBootstrappers();
+        $this->faker->forgetExtensions();
+        $this->faker->forgetModifiers();
+        $this->faker->forgetStrategies();
+
+        (new FakerServiceProvider())->boot();
+
+        return new Container(new Mt19937(19937), false);
     }
 }