[5.x] Use multibyte methods for obfuscate (#10201)

Co-authored-by: Jason Varga <jason@pixelfear.com>

src/Support/Html.php

@@ -219,20 +219,18 @@ public static function obfuscate($value)
     {
         $safe = '';
 
-        foreach (str_split($value) as $letter) {
-            if (ord($letter) > 128) {
-                return $letter;
-            }
+        foreach (mb_str_split($value) as $letter) {
+            $ordValue = mb_ord($letter);
 
             // To properly obfuscate the value, we will randomly convert each letter to
             // its entity or hexadecimal representation, keeping a bot from sniffing
             // the randomly obfuscated letters out of the string on the responses.
             switch (rand(1, 3)) {
                 case 1:
-                    $safe .= '&#'.ord($letter).';';
+                    $safe .= '&#'.$ordValue.';';
                     break;
                 case 2:
-                    $safe .= '&#x'.dechex(ord($letter)).';';
+                    $safe .= '&#x'.dechex($ordValue).';';
                     break;
                 case 3:
                     $safe .= $letter;

tests/Modifiers/ObfuscateTest.php

@@ -7,11 +7,35 @@
 
 class ObfuscateTest extends TestCase
 {
-    /** @test */
-    public function it_obfuscates_a_string(): void
+    /**
+     * @test
+     *
+     * @dataProvider seedProvider
+     */
+    public function it_obfuscates_strings($seed, $value, $expected)
     {
-        $modified = $this->modify('A');
-        $this->assertTrue(in_array($modified, ['A', 'A', 'A']));
+        mt_srand($seed); // make rand predictable for testing.
+
+        $this->assertEquals($expected, $this->modify($value));
+
+        srand(); // reset to not affect other tests.
+    }
+
+    public static function seedProvider()
+    {
+        return [
+            'A, case 1' => [1, 'A', 'A'],
+            'A, case 2' => [2, 'A', 'A'],
+            'A, case 3' => [5, 'A', 'A'],
+
+            'é, case 1' => [1, 'é', 'é'],
+            'é, case 2' => [2, 'é', 'é'],
+            'é, case 3' => [5, 'é', 'é'],
+
+            '🐘, case 1' => [1, '🐘', '🐘'],
+            '🐘, case 2' => [2, '🐘', '🐘'],
+            '🐘, case 3' => [5, '🐘', '🐘'],
+        ];
     }
 
     private function modify($value)