Prepare a test case for 9839 compatibility

tests/PhpSrcGH9839Test.php

@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Arokettu\Random\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Random\Engine\Mt19937;
+use Random\Randomizer;
+
+/**
+ * @see https://github.com/php/php-src/pull/9839
+ * @see https://github.com/arokettu/php-random-polyfill/issues/4#issuecomment-1293353629
+ */
+class PhpSrcGH9839Test extends TestCase
+{
+    // just so we don't break the regular algo
+    public function testShuffleBytes(): void
+    {
+        $digits = '0123456789';
+        $expected = '0827613495';
+
+        $r = new Randomizer(new Mt19937(1, \MT_RAND_MT19937));
+
+        $s = $r->shuffleBytes($digits);
+
+        self::assertEquals($expected, $s);
+    }
+
+    public function testShuffleBytesCompat(): void
+    {
+        $digits = '0123456789';
+        $expected = '8926013475'; // not 8132476905
+
+        $r = new Randomizer(new Mt19937(1, \MT_RAND_PHP));
+
+        $s = $r->shuffleBytes($digits);
+
+        self::assertEquals($expected, $s);
+    }
+
+    // just so we don't break the regular algo
+    public function testShuffleArray(): void
+    {
+        $digits = \str_split('0123456789');
+        $expected = \str_split('0827613495');
+
+        $r = new Randomizer(new Mt19937(1, \MT_RAND_MT19937));
+
+        $s = $r->shuffleArray($digits);
+
+        self::assertEquals($expected, $s);
+    }
+
+    public function testShuffleArrayCompat(): void
+    {
+        $digits = \str_split('0123456789');
+        $expected = \str_split('8926013475'); // not 8132476905
+
+        $r = new Randomizer(new Mt19937(1, \MT_RAND_PHP));
+
+        $s = $r->shuffleArray($digits);
+
+        self::assertEquals($expected, $s);
+    }
+}