diff --git a/ext/random/tests/02_engine/all_serialize_native.phpt b/ext/random/tests/02_engine/all_serialize_native.phpt
index df56456d133..cadb208a664 100644
--- a/ext/random/tests/02_engine/all_serialize_native.phpt
+++ b/ext/random/tests/02_engine/all_serialize_native.phpt
@@ -13,6 +13,8 @@ $engines[] = new PcgOneseq128XslRr64(1234);
 $engines[] = new Xoshiro256StarStar(1234);
 
 foreach ($engines as $engine) {
+    echo $engine::class, PHP_EOL;
+
     for ($i = 0; $i < 10_000; $i++) {
         $engine->generate();
     }
@@ -21,9 +23,7 @@ foreach ($engines as $engine) {
 
     for ($i = 0; $i < 10_000; $i++) {
         if ($engine->generate() !== $engine2->generate()) {
-            $className = $engine::class;
-
-            die("failure: {$className} at {$i}");
+            die("failure: state differs at {$i}");
         }
     }
 }
@@ -32,4 +32,7 @@ die('success');
 
 ?>
 --EXPECT--
+Random\Engine\Mt19937
+Random\Engine\PcgOneseq128XslRr64
+Random\Engine\Xoshiro256StarStar
 success
diff --git a/ext/random/tests/02_engine/all_serialize_user.phpt b/ext/random/tests/02_engine/all_serialize_user.phpt
index de3fe2f8292..9ae742314f5 100644
--- a/ext/random/tests/02_engine/all_serialize_user.phpt
+++ b/ext/random/tests/02_engine/all_serialize_user.phpt
@@ -4,18 +4,11 @@ Random: Engine: Serialization of user engines must preserve the sequence
 <?php
 
 use Random\Engine;
+use Random\Engine\Test\TestShaEngine;
 
-final class User64 implements Engine
-{
-    private int $count = 0;
+require __DIR__ . "/../engines.inc";
 
-    public function generate(): string
-    {
-        return pack('P*', ++$this->count);
-    }
-}
-
-final class User32 implements Engine
+final class CountingEngine32 implements Engine
 {
     private int $count = 0;
 
@@ -26,12 +19,12 @@ final class User32 implements Engine
 }
 
 $engines = [];
-if (PHP_INT_SIZE >= 8) {
-    $engines[] = new User64();
-}
-$engines[] = new User32();
+$engines[] = new CountingEngine32();
+$engines[] = new TestShaEngine();
 
 foreach ($engines as $engine) {
+    echo $engine::class, PHP_EOL;
+
     for ($i = 0; $i < 10_000; $i++) {
         $engine->generate();
     }
@@ -40,9 +33,7 @@ foreach ($engines as $engine) {
 
     for ($i = 0; $i < 10_000; $i++) {
         if ($engine->generate() !== $engine2->generate()) {
-            $className = $engine::class;
-
-            die("failure: {$className} at {$i}");
+            die("failure: state differs at {$i}");
         }
     }
 }
@@ -51,4 +42,6 @@ die('success');
 
 ?>
 --EXPECT--
+CountingEngine32
+Random\Engine\Test\TestShaEngine
 success
diff --git a/ext/random/tests/02_engine/pcgoneseq128xslrr64_jump_error.phpt b/ext/random/tests/02_engine/pcgoneseq128xslrr64_jump_error.phpt
index 02be8ecb6c9..cbc6e370b17 100644
--- a/ext/random/tests/02_engine/pcgoneseq128xslrr64_jump_error.phpt
+++ b/ext/random/tests/02_engine/pcgoneseq128xslrr64_jump_error.phpt
@@ -16,7 +16,7 @@ try {
 
 for ($i = 0; $i < 10_000; $i++) {
     if ($engine->generate() !== $referenceEngine->generate()) {
-        die('failure: state changed');
+        die("failure: state differs at {$i}");
     }
 }
 
diff --git a/ext/random/tests/02_engine/user_compatibility.phpt b/ext/random/tests/02_engine/user_compatibility.phpt
index 11ac4514312..401541e7141 100644
--- a/ext/random/tests/02_engine/user_compatibility.phpt
+++ b/ext/random/tests/02_engine/user_compatibility.phpt
@@ -6,19 +6,10 @@ Random: Engine: Native engines can be wrapped without changing their sequence
 use Random\Engine;
 use Random\Engine\Mt19937;
 use Random\Engine\PcgOneseq128XslRr64;
+use Random\Engine\Test\TestWrapperEngine;
 use Random\Engine\Xoshiro256StarStar;
 
-class WrapperEngine implements Engine
-{
-    public function __construct(private readonly Engine $engine)
-    {
-    }
-
-    public function generate(): string
-    {
-        return $this->engine->generate();
-    }
-}
+require __DIR__ . "/../engines.inc";
 
 $engines = [];
 $engines[] = new Mt19937(1234);
@@ -26,13 +17,14 @@ $engines[] = new PcgOneseq128XslRr64(1234);
 $engines[] = new Xoshiro256StarStar(1234);
 
 foreach ($engines as $engine) {
+    echo $engine::class, PHP_EOL;
+
     $native_engine = clone $engine;
-    $user_engine = new WrapperEngine(clone $engine);
+    $user_engine = new TestWrapperEngine(clone $engine);
 
     for ($i = 0; $i < 10_000; $i++) {
         if ($native_engine->generate() !== $user_engine->generate()) {
-            $className = $engine::class;
-            die("failure: {$className} at {$i}");
+            die("failure: state differs at {$i}");
         }
     }
 }
@@ -41,4 +33,7 @@ die('success');
 
 ?>
 --EXPECT--
+Random\Engine\Mt19937
+Random\Engine\PcgOneseq128XslRr64
+Random\Engine\Xoshiro256StarStar
 success
diff --git a/ext/random/tests/02_engine/xoshiro256starstar_seed.phpt b/ext/random/tests/02_engine/xoshiro256starstar_seed.phpt
index f4fa0a40b98..ec31c358fd6 100644
--- a/ext/random/tests/02_engine/xoshiro256starstar_seed.phpt
+++ b/ext/random/tests/02_engine/xoshiro256starstar_seed.phpt
@@ -6,17 +6,17 @@ Random: Engine: Xoshiro256StarStar: The seed parameter must work as expected
 use Random\Engine\Xoshiro256StarStar;
 
 echo "Random integer seed", PHP_EOL;
-$engine = new Xoshiro256StarStar(\random_int(\PHP_INT_MIN, \PHP_INT_MAX));
+$engine = new Xoshiro256StarStar(random_int(PHP_INT_MIN, PHP_INT_MAX));
 echo PHP_EOL, PHP_EOL;
 
 echo "Random string seed", PHP_EOL;
-$engine = new Xoshiro256StarStar(\random_bytes(32));
+$engine = new Xoshiro256StarStar(random_bytes(32));
 echo PHP_EOL, PHP_EOL;
 
 echo "Invalid data type", PHP_EOL;
 try {
     $engine = new Xoshiro256StarStar(1.0);
-} catch (\Throwable $e) {
+} catch (Throwable $e) {
     echo $e->getMessage(), PHP_EOL;
 }
 echo PHP_EOL, PHP_EOL;
@@ -24,15 +24,15 @@ echo PHP_EOL, PHP_EOL;
 echo "Invalid string seed length", PHP_EOL;
 try {
     $engine = new Xoshiro256StarStar('foobar');
-} catch (\Throwable $e) {
+} catch (Throwable $e) {
     echo $e->getMessage(), PHP_EOL;
 }
 echo PHP_EOL, PHP_EOL;
 
 echo "Null seed", PHP_EOL;
 try {
-    $engine = new Random\Engine\Xoshiro256StarStar(\str_repeat("\x00", 32));
-} catch (\Throwable $e) {
+    $engine = new Xoshiro256StarStar(str_repeat("\x00", 32));
+} catch (Throwable $e) {
     echo $e->getMessage(), PHP_EOL;
 }
 echo PHP_EOL, PHP_EOL;
diff --git a/ext/random/tests/03_randomizer/basic.phpt b/ext/random/tests/03_randomizer/basic.phpt
deleted file mode 100644
index a2f6378a71e..00000000000
--- a/ext/random/tests/03_randomizer/basic.phpt
+++ /dev/null
@@ -1,81 +0,0 @@
---TEST--
-Random: Randomizer: basic
---FILE--
-<?php
-
-$engines = [];
-$engines[] = new Random\Engine\Mt19937(\random_int(\PHP_INT_MIN, \PHP_INT_MAX), MT_RAND_MT19937);
-$engines[] = new Random\Engine\Mt19937(\random_int(\PHP_INT_MIN, \PHP_INT_MAX), MT_RAND_PHP);
-$engines[] = new Random\Engine\PcgOneseq128XslRr64(\random_int(\PHP_INT_MIN, \PHP_INT_MAX));
-$engines[] = new Random\Engine\Xoshiro256StarStar(\random_int(\PHP_INT_MIN, \PHP_INT_MAX));
-$engines[] = new Random\Engine\Secure(); 
-$engines[] = new class () implements Random\Engine {
-    public function generate(): string
-    {
-        return \random_bytes(16);
-    }
-};
-class UserEngine implements Random\Engine
-{
-    public function generate(): string
-    {
-        return \random_bytes(16);
-    }
-}
-$engines[] = new UserEngine();
-
-foreach ($engines as $engine) {
-    $randomizer = new Random\Randomizer($engine);
-
-    // nextInt
-    for ($i = 0; $i < 1000; $i++) {
-        try {
-            $randomizer->nextInt();
-        } catch (\Random\RandomException $e) {
-            if ($e->getMessage() !== 'Generated value exceeds size of int') {
-                die($engine::class . ": nextInt: failure: {$e->getMessage()}");
-            }
-        }
-    }
-
-    // getInt
-    for ($i = 0; $i < 1000; $i++) {
-        $result = $randomizer->getInt(-50, 50);
-        if ($result > 50 || $result < -50) {
-            die($engine::class . ': getInt: failure');
-        }
-    }
-
-    // getBytes
-    for ($i = 0; $i < 1000; $i++) {
-        $length = \random_int(1, 1024);
-        if (\strlen($randomizer->getBytes($length)) !== $length) {
-            die($engine::class . ': getBytes: failure');
-        }
-    }
-
-    // shuffleArray
-    $array = range(1, 1000);
-    $shuffled_array = $randomizer->shuffleArray($array);
-    (function () use ($array, $shuffled_array): void {
-        for ($i = 0; $i < count($array); $i++) {
-            if ($array[$i] !== $shuffled_array[$i]) {
-                return;
-            }
-        }
-
-        die($engine::class . ': shuffleArray: failure');
-    })();
-
-    // shuffleBytes
-    $string = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.';
-    $shuffled_string = $randomizer->shuffleBytes($string);
-    if ($string === $shuffled_string) {
-        die($engine::class . ': shuffleBytes: failure');
-    }
-}
-
-die('success');
-?>
---EXPECTF--
-success
diff --git a/ext/random/tests/03_randomizer/pick_array_keys.phpt b/ext/random/tests/03_randomizer/compatibility_array_rand.phpt
similarity index 73%
rename from ext/random/tests/03_randomizer/pick_array_keys.phpt
rename to ext/random/tests/03_randomizer/compatibility_array_rand.phpt
index 168d01dbc42..364267faf6b 100644
--- a/ext/random/tests/03_randomizer/pick_array_keys.phpt
+++ b/ext/random/tests/03_randomizer/compatibility_array_rand.phpt
@@ -1,8 +1,11 @@
 --TEST--
-Random: Randomizer: pickArrayKeys
+Random: Randomizer: The Mt19937 engine and pickArrayKeys are consistent with array_rand()
 --FILE--
 <?php
 
+use Random\Engine\Mt19937;
+use Random\Randomizer;
+
 $map = ['foo' => 0, 'bar' => 1, 'baz' => 2];
 $list = range(1, 10);
 
@@ -14,7 +17,7 @@ $mapPickTwoFunc = array_rand($map, 2);
 $listPickOneFunc = array_rand($list, 1);
 $listPickTwoFunc = array_rand($list, 2);
 
-$randomizer = new \Random\Randomizer(new \Random\Engine\Mt19937(1234));
+$randomizer = new Randomizer(new Mt19937(1234));
 
 [$mapPickOneMethod] = $randomizer->pickArrayKeys($map, 1);
 $mapPickTwoMethod = $randomizer->pickArrayKeys($map, 2);
@@ -24,25 +27,30 @@ $listPickTwoMethod = $randomizer->pickArrayKeys($list, 2);
 
 if ($mapPickOneFunc !== $mapPickOneMethod) {
     var_dump($mapPickOneFunc, $mapPickOneMethod);
-    die('failure mapPickOne');
+
+    die('failure: mapPickOne');
 }
 
 if ($mapPickTwoFunc !== $mapPickTwoMethod) {
     var_dump($mapPickTwoFunc, $mapPickTwoMethod);
-    die('failure mapPickTwo');
+
+    die('failure: mapPickTwo');
 }
 
 if ($listPickOneFunc !== $listPickOneMethod) {
     var_dump($listPickOneFunc, $listPickOneMethod);
-    die('failure listPickOne');
+
+    die('failure: listPickOne');
 }
 
 if ($listPickTwoFunc !== $listPickTwoMethod) {
     var_dump($listPickTwoFunc, $listPickOneMethod);
-    die('failure listPickTwo');
+
+    die('failure: listPickTwo');
 }
 
 die('success');
+
 ?>
---EXPECTF--
+--EXPECT--
 success
diff --git a/ext/random/tests/03_randomizer/compatibility_mt.phpt b/ext/random/tests/03_randomizer/compatibility_mt.phpt
deleted file mode 100644
index 9740a494d6f..00000000000
--- a/ext/random/tests/03_randomizer/compatibility_mt.phpt
+++ /dev/null
@@ -1,24 +0,0 @@
---TEST--
-Random: Randomizer: Compatibility: Mt19937
---FILE--
-<?php
-
-$randomizer = new \Random\Randomizer(new \Random\Engine\Mt19937(1234, \MT_RAND_PHP));
-\mt_srand(1234, \MT_RAND_PHP);
-for ($i = 0; $i < 1000; $i++) {
-    if ($randomizer->nextInt() !== \mt_rand()) {
-        die('failure');
-    }
-}
-
-$randomizer = new \Random\Randomizer(new \Random\Engine\Mt19937(1234, \MT_RAND_MT19937));
-\mt_srand(1234, \MT_RAND_MT19937);
-for ($i = 0; $i < 1000; $i++) {
-    if ($randomizer->nextInt() !== \mt_rand()) {
-        die('failure');
-    }
-}
-
-die('success');
---EXPECT--
-success
diff --git a/ext/random/tests/03_randomizer/compatibility_mt_rand.phpt b/ext/random/tests/03_randomizer/compatibility_mt_rand.phpt
new file mode 100644
index 00000000000..a69c50d0cb6
--- /dev/null
+++ b/ext/random/tests/03_randomizer/compatibility_mt_rand.phpt
@@ -0,0 +1,49 @@
+--TEST--
+Random: Randomizer: The Mt19937 engine is a drop-in replacement for mt_rand()
+--FILE--
+<?php
+
+use Random\Randomizer;
+use Random\Engine\Mt19937;
+
+echo "MT_RAND_PHP", PHP_EOL;
+
+$randomizer = new Randomizer(new Mt19937(1234, MT_RAND_PHP));
+mt_srand(1234, MT_RAND_PHP);
+
+for ($i = 0; $i < 10_000; $i++) {
+    if ($randomizer->nextInt() !== mt_rand()) {
+        die("failure: state differs at {$i} for nextInt()");
+    }
+}
+
+for ($i = 0; $i < 10_000; $i++) {
+    if ($randomizer->getInt(0, $i) !== mt_rand(0, $i)) {
+        die("failure: state differs at {$i} for getInt()");
+    }
+}
+
+echo "MT_RAND_MT19937", PHP_EOL;
+
+$randomizer = new Randomizer(new Mt19937(1234, MT_RAND_MT19937));
+mt_srand(1234, MT_RAND_MT19937);
+
+for ($i = 0; $i < 10_000; $i++) {
+    if ($randomizer->nextInt() !== mt_rand()) {
+        die("failure: state differs at {$i} for nextInt()");
+    }
+}
+
+for ($i = 0; $i < 10_000; $i++) {
+    if ($randomizer->getInt(0, $i) !== mt_rand(0, $i)) {
+        die("failure: state differs at {$i} for getInt()");
+    }
+}
+
+die('success');
+
+?>
+--EXPECT--
+MT_RAND_PHP
+MT_RAND_MT19937
+success
diff --git a/ext/random/tests/03_randomizer/compatibility_user.phpt b/ext/random/tests/03_randomizer/compatibility_user.phpt
index 3b4251aecbe..a4601b55ab0 100644
--- a/ext/random/tests/03_randomizer/compatibility_user.phpt
+++ b/ext/random/tests/03_randomizer/compatibility_user.phpt
@@ -1,80 +1,43 @@
 --TEST--
-Random: Randomizer: Compatibility: user
+Random: Randomizer: Native engines can be wrapped without changing their sequence
 --FILE--
 <?php
 
-$native_randomizer = new \Random\Randomizer(new \Random\Engine\Mt19937(1234));
-$user_randomizer = new \Random\Randomizer(new class () implements \Random\Engine {
-    public function __construct(private $engine = new \Random\Engine\Mt19937(1234))
-    {
-    }
+use Random\Engine;
+use Random\Engine\Mt19937;
+use Random\Engine\PcgOneseq128XslRr64;
+use Random\Engine\Test\TestWrapperEngine;
+use Random\Engine\Xoshiro256StarStar;
+use Random\Randomizer;
 
-    public function generate(): string
-    {
-        return $this->engine->generate();
-    }
-});
-for ($i = 0; $i < 1000; $i++) {
-    $native = $native_randomizer->nextInt();
-    $user = $user_randomizer->nextInt();
-    if ($native !== $user) {
-        die("failure Mt19937 i: {$i} native: {$native} user: {$user}");
-    }
-}
+require __DIR__ . "/../engines.inc";
 
-try {
-    $native_randomizer = new \Random\Randomizer(new \Random\Engine\PcgOneseq128XslRr64(1234));
-    $user_randomizer = new \Random\Randomizer(new class () implements \Random\Engine {
-        public function __construct(private $engine = new \Random\Engine\PcgOneseq128XslRr64(1234))
-        {
-        }
+$engines = [];
+$engines[] = new Mt19937(1234);
+$engines[] = new PcgOneseq128XslRr64(1234);
+$engines[] = new Xoshiro256StarStar(1234);
+
+foreach ($engines as $engine) {
+    echo $engine::class, PHP_EOL;
+
+    $native_randomizer = new Randomizer(clone $engine);
+    $user_randomizer = new Randomizer(new TestWrapperEngine(clone $engine));
+
+    for ($i = 0; $i < 10_000; $i++) {
+        $native = $native_randomizer->getInt(0, $i);
+        $user = $user_randomizer->getInt(0, $i);
 
-        public function generate(): string
-        {
-            return $this->engine->generate();
-        }
-    });
-    
-    for ($i = 0; $i < 1000; $i++) {
-        $native = $native_randomizer->nextInt();
-        $user = $user_randomizer->nextInt();
         if ($native !== $user) {
-            die("failure PcgOneseq128XslRr64 i: {$i} native: {$native} user: {$user}");
+            die("failure: state differs at {$i}");
         }
     }
-} catch (\Random\RandomException $e) {
-    if ($e->getMessage() !== 'Generated value exceeds size of int') {
-        throw $e;
-    }
-}
-
-try {
-    $native_randomizer = new \Random\Randomizer(new \Random\Engine\Xoshiro256StarStar(1234));
-    $user_randomizer = new \Random\Randomizer(new class () implements \Random\Engine {
-        public function __construct(private $engine = new \Random\Engine\Xoshiro256StarStar(1234))
-        {
-        }
-
-        public function generate(): string
-        {
-            return $this->engine->generate();
-        }
-    });
-    
-    for ($i = 0; $i < 1000; $i++) {
-        $native = $native_randomizer->nextInt();
-        $user = $user_randomizer->nextInt();
-        if ($native !== $user) {
-            die("failure Xoshiro256StarStar i: {$i} native: {$native} user: {$user}");
-        }
-    }
-} catch (\Random\RandomException $e) {
-    if ($e->getMessage() !== 'Generated value exceeds size of int') {
-        throw $e;
-    }
 }
 
 die('success');
+
 ?>
 --EXPECT--
+Random\Engine\Mt19937
+Random\Engine\PcgOneseq128XslRr64
+Random\Engine\Xoshiro256StarStar
 success
diff --git a/ext/random/tests/03_randomizer/construct_twice.phpt b/ext/random/tests/03_randomizer/construct_twice.phpt
index ed2a667e2af..7128338ade9 100644
--- a/ext/random/tests/03_randomizer/construct_twice.phpt
+++ b/ext/random/tests/03_randomizer/construct_twice.phpt
@@ -1,46 +1,47 @@
 --TEST--
-Random: Randomizer: Disallow manually calling __construct
+Random: Randomizer: Calling __construct() fails due to readonly $engine property
 --FILE--
 <?php
 
-final class UserEngine implements \Random\Engine
-{
-    public function generate(): string
-    {
-        return \random_byte(4); /* 32-bit */
-    }
-}
+use Random\Engine;
+use Random\Engine\PcgOneseq128XslRr64;
+use Random\Engine\Test\TestShaEngine;
+use Random\Engine\Xoshiro256StarStar;
+use Random\Randomizer;
+
+require __DIR__ . "/../engines.inc";
 
 try {
-    (new \Random\Randomizer())->__construct();
-} catch (\Error $e) {
-    echo $e->getMessage() . PHP_EOL;
-}
-
-try {
-    $r = new \Random\Randomizer(new \Random\Engine\Xoshiro256StarStar());
-    $r->__construct(new \Random\Engine\PcgOneseq128XslRr64());
-} catch (\Error $e) {
-    echo $e->getMessage() . PHP_EOL;
-}
-
-try {
-    $r = new \Random\Randomizer(new \UserEngine());
-    $r->__construct(new \UserEngine());
-} catch (\Error $e) {
-    echo $e->getMessage() . PHP_EOL;
-}
-
-try {
-    $r = new \Random\Randomizer(new \Random\Engine\Xoshiro256StarStar());
-    $r->__construct(new \UserEngine());
-} catch (\Error $e) {
+    (new Randomizer())->__construct();
+} catch (Error $e) {
     echo $e->getMessage(), PHP_EOL;
 }
 
-var_dump($r->engine::class);
+try {
+    $randomizer = new Randomizer(new Xoshiro256StarStar());
+    $randomizer->__construct(new PcgOneseq128XslRr64());
+} catch (Error $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    $randomizer = new Randomizer(new TestShaEngine("1234"));
+    $randomizer->__construct(new TestShaEngine("1234"));
+} catch (Error $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    $randomizer = new Randomizer(new Xoshiro256StarStar());
+    $randomizer->__construct(new TestShaEngine("1234"));
+} catch (Error $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+var_dump($randomizer->engine::class);
 
 die('success');
+
 ?>
 --EXPECT--
 Cannot modify readonly property Random\Randomizer::$engine
diff --git a/ext/random/tests/03_randomizer/engine_unsafe_biased.phpt b/ext/random/tests/03_randomizer/engine_unsafe_biased.phpt
new file mode 100644
index 00000000000..09fbd85b54e
--- /dev/null
+++ b/ext/random/tests/03_randomizer/engine_unsafe_biased.phpt
@@ -0,0 +1,58 @@
+--TEST--
+Random: Randomizer: Heavily biased engines are detected and rejected
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Randomizer;
+
+final class HeavilyBiasedEngine implements Engine
+{
+    public function generate(): string
+    {
+        return str_repeat("\xff", PHP_INT_SIZE);
+    }
+}
+
+function randomizer(): Randomizer
+{
+    return new Randomizer(new HeavilyBiasedEngine());
+}
+
+try {
+    var_dump(randomizer()->getInt(0, 1234));
+} catch (Random\BrokenRandomEngineError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    var_dump(randomizer()->nextInt());
+} catch (Random\BrokenRandomEngineError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    var_dump(bin2hex(randomizer()->getBytes(1)));
+} catch (Random\BrokenRandomEngineError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    var_dump(randomizer()->shuffleArray(range(1, 1234)));
+} catch (Random\BrokenRandomEngineError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    var_dump(randomizer()->shuffleBytes('foobar'));
+} catch (Random\BrokenRandomEngineError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+?>
+--EXPECTF--
+Failed to generate an acceptable random number in 50 attempts
+int(%d)
+string(2) "ff"
+Failed to generate an acceptable random number in 50 attempts
+Failed to generate an acceptable random number in 50 attempts
diff --git a/ext/random/tests/03_randomizer/engine_unsafe_empty_string.phpt b/ext/random/tests/03_randomizer/engine_unsafe_empty_string.phpt
new file mode 100644
index 00000000000..01bd293bc05
--- /dev/null
+++ b/ext/random/tests/03_randomizer/engine_unsafe_empty_string.phpt
@@ -0,0 +1,58 @@
+--TEST--
+Random: Randomizer: Engines returning an empty string are detected and rejected
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Randomizer;
+
+final class EmptyStringEngine implements Engine
+{
+    public function generate(): string
+    {
+        return '';
+    }
+}
+
+function randomizer(): Randomizer
+{
+    return new Randomizer(new EmptyStringEngine());
+}
+
+try {
+    var_dump(randomizer()->getInt(0, 1234));
+} catch (Random\BrokenRandomEngineError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    var_dump(randomizer()->nextInt());
+} catch (Random\BrokenRandomEngineError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    var_dump(bin2hex(randomizer()->getBytes(1)));
+} catch (Random\BrokenRandomEngineError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    var_dump(randomizer()->shuffleArray(range(1, 1234)));
+} catch (Random\BrokenRandomEngineError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    var_dump(randomizer()->shuffleBytes('foobar'));
+} catch (Random\BrokenRandomEngineError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+?>
+--EXPECT--
+A random engine must return a non-empty string
+A random engine must return a non-empty string
+A random engine must return a non-empty string
+A random engine must return a non-empty string
+A random engine must return a non-empty string
diff --git a/ext/random/tests/03_randomizer/engine_unsafe_exits.phpt b/ext/random/tests/03_randomizer/engine_unsafe_exits.phpt
new file mode 100644
index 00000000000..cb598872d97
--- /dev/null
+++ b/ext/random/tests/03_randomizer/engine_unsafe_exits.phpt
@@ -0,0 +1,23 @@
+--TEST--
+Random: Randomizer: Engines calling exit() are gracefully handled
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Randomizer;
+
+final class ExitingEngine implements Engine
+{
+    public function generate(): string
+    {
+        exit("Exit\n");
+    }
+}
+
+$randomizer = new Randomizer(new ExitingEngine());
+
+var_dump($randomizer->getBytes(1));
+
+?>
+--EXPECT--
+Exit
diff --git a/ext/random/tests/03_randomizer/engine_unsafe_throws.phpt b/ext/random/tests/03_randomizer/engine_unsafe_throws.phpt
new file mode 100644
index 00000000000..bfb679f81a2
--- /dev/null
+++ b/ext/random/tests/03_randomizer/engine_unsafe_throws.phpt
@@ -0,0 +1,28 @@
+--TEST--
+Random: Randomizer: Engines throwing an exception are gracefully handled
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Randomizer;
+
+final class ThrowingEngine implements Engine
+{
+    public function generate(): string
+    {
+        throw new Exception('Error');
+    }
+} 
+
+$randomizer = new Randomizer(new ThrowingEngine());
+
+var_dump($randomizer->getBytes(1));
+
+?>
+--EXPECTF--
+Fatal error: Uncaught Exception: Error in %s:%d
+Stack trace:
+#0 [internal function]: ThrowingEngine->generate()
+#1 %s(%d): Random\Randomizer->getBytes(1)
+#2 {main}
+  thrown in %s on line %d
diff --git a/ext/random/tests/03_randomizer/get_bytes.phpt b/ext/random/tests/03_randomizer/get_bytes.phpt
deleted file mode 100644
index c6b4a59475e..00000000000
--- a/ext/random/tests/03_randomizer/get_bytes.phpt
+++ /dev/null
@@ -1,40 +0,0 @@
---TEST--
-Random: Randomizer: getBytes
---FILE--
-<?php
-
-$randomizer = new \Random\Randomizer (
-    new class () implements \Random\Engine
-    {
-        private int $count = 0;
-
-        public function generate(): string
-        {
-            if ($this->count > 5) {
-                die('overflow');
-            }
-
-            return match ($this->count++) {
-                0 => 'H',
-                1 => 'e',
-                2 => 'll',
-                3 => 'o',
-                4 => 'abcdefghijklmnopqrstuvwxyz', // 208 bits
-                5 => 'success',
-                default => \random_bytes(16),
-            };
-        }
-    }
-);
-
-echo $randomizer->getBytes(5) . PHP_EOL; // Hello
-
-echo $randomizer->getBytes(8) . PHP_EOL; // abcdefgh (64 bits)
-
-die($randomizer->getBytes(7));
-
-?>
---EXPECTF--
-Hello
-abcdefgh
-success
diff --git a/ext/random/tests/03_randomizer/get_int_user.phpt b/ext/random/tests/03_randomizer/get_int_user.phpt
deleted file mode 100644
index d6c99531431..00000000000
--- a/ext/random/tests/03_randomizer/get_int_user.phpt
+++ /dev/null
@@ -1,22 +0,0 @@
---TEST--
-Random: Randomizer: User Engine results are correctly expanded for getInt()
---FILE--
-<?php
-
-$randomizer = new \Random\Randomizer (
-    new class () implements \Random\Engine
-    {
-        public $count = 0;
-
-        public function generate(): string
-        {
-            return "\x01\x02\x03\x04\x05\x06\x07\x08"[$this->count++];
-        }
-    }
-);
-
-var_dump(bin2hex(pack('V', $randomizer->getInt(0, 0xFFFFFF))));
-
-?>
---EXPECT--
-string(8) "01020300"
diff --git a/ext/random/tests/03_randomizer/methods/getBytes.phpt b/ext/random/tests/03_randomizer/methods/getBytes.phpt
new file mode 100644
index 00000000000..a236e9746fa
--- /dev/null
+++ b/ext/random/tests/03_randomizer/methods/getBytes.phpt
@@ -0,0 +1,47 @@
+--TEST--
+Random: Randomizer: getBytes(): Basic functionality
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Engine\Mt19937;
+use Random\Engine\PcgOneseq128XslRr64;
+use Random\Engine\Secure;
+use Random\Engine\Test\TestShaEngine;
+use Random\Engine\Xoshiro256StarStar;
+use Random\Randomizer;
+
+require __DIR__ . "/../../engines.inc";
+
+$engines = [];
+$engines[] = new Mt19937(null, MT_RAND_MT19937);
+$engines[] = new Mt19937(null, MT_RAND_PHP);
+$engines[] = new PcgOneseq128XslRr64();
+$engines[] = new Xoshiro256StarStar();
+$engines[] = new Secure();
+$engines[] = new TestShaEngine();
+
+foreach ($engines as $engine) {
+    echo $engine::class, PHP_EOL;
+
+    $randomizer = new Randomizer($engine);
+
+    // Using 10_000 is very slow.
+    for ($i = 1; $i < 1_000; $i++) {
+        if (\strlen($randomizer->getBytes($i)) !== $i) {
+            die("failure: incorrect string length at {$i}");
+        }
+    }
+}
+
+die('success');
+
+?>
+--EXPECT--
+Random\Engine\Mt19937
+Random\Engine\Mt19937
+Random\Engine\PcgOneseq128XslRr64
+Random\Engine\Xoshiro256StarStar
+Random\Engine\Secure
+Random\Engine\Test\TestShaEngine
+success
diff --git a/ext/random/tests/03_randomizer/methods/getBytes_expansion.phpt b/ext/random/tests/03_randomizer/methods/getBytes_expansion.phpt
new file mode 100644
index 00000000000..750b7870e40
--- /dev/null
+++ b/ext/random/tests/03_randomizer/methods/getBytes_expansion.phpt
@@ -0,0 +1,43 @@
+--TEST--
+Random: Randomizer: getBytes(): Returned bytes are consistently expanded
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Randomizer;
+
+final class TestEngine implements Engine
+{
+    private int $count = 0;
+
+    public function generate(): string
+    {
+        return match ($this->count++) {
+            0 => 'H',
+            1 => 'e',
+            2 => 'll',
+            3 => 'o',
+            4 => 'abcdefghijklmnopqrstuvwxyz',
+            5 => 'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
+            6 => 'success',
+            default => throw new \Exception('Unhandled'),
+        };
+    }
+}
+
+$randomizer = new Randomizer(new TestEngine());
+
+// 0-3: "Hello" - Insufficient bytes are concatenated.
+var_dump($randomizer->getBytes(5));
+
+// 4-5: "abcdefghABC" - Returned values are truncated to 64-bits for technical reasons, thus dropping i-z.
+var_dump($randomizer->getBytes(11));
+
+// 6: "success"
+var_dump($randomizer->getBytes(7));
+
+?>
+--EXPECT--
+string(5) "Hello"
+string(11) "abcdefghABC"
+string(7) "success"
diff --git a/ext/random/tests/03_randomizer/methods/getInt.phpt b/ext/random/tests/03_randomizer/methods/getInt.phpt
new file mode 100644
index 00000000000..faa098ade13
--- /dev/null
+++ b/ext/random/tests/03_randomizer/methods/getInt.phpt
@@ -0,0 +1,54 @@
+--TEST--
+Random: Randomizer: getInt(): Basic functionality
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Engine\Mt19937;
+use Random\Engine\PcgOneseq128XslRr64;
+use Random\Engine\Secure;
+use Random\Engine\Test\TestShaEngine;
+use Random\Engine\Xoshiro256StarStar;
+use Random\Randomizer;
+
+require __DIR__ . "/../../engines.inc";
+
+$engines = [];
+$engines[] = new Mt19937(null, MT_RAND_MT19937);
+$engines[] = new Mt19937(null, MT_RAND_PHP);
+$engines[] = new PcgOneseq128XslRr64();
+$engines[] = new Xoshiro256StarStar();
+$engines[] = new Secure();
+$engines[] = new TestShaEngine();
+
+foreach ($engines as $engine) {
+    echo $engine::class, PHP_EOL;
+
+    $randomizer = new Randomizer($engine);
+
+    // Basic range test.
+    for ($i = 0; $i < 10_000; $i++) {
+        $result = $randomizer->getInt(-$i, $i);
+
+        if ($result > $i || $result < -$i) {
+            die("failure: out of range at {$i}");
+        }
+    }
+
+    // Test that extreme ranges do not throw.
+    for ($i = 0; $i < 10_000; $i++) {
+        $randomizer->getInt(PHP_INT_MIN, PHP_INT_MAX);
+    }
+}
+
+die('success');
+
+?>
+--EXPECT--
+Random\Engine\Mt19937
+Random\Engine\Mt19937
+Random\Engine\PcgOneseq128XslRr64
+Random\Engine\Xoshiro256StarStar
+Random\Engine\Secure
+Random\Engine\Test\TestShaEngine
+success
diff --git a/ext/random/tests/03_randomizer/methods/getInt_expansion_32.phpt b/ext/random/tests/03_randomizer/methods/getInt_expansion_32.phpt
new file mode 100644
index 00000000000..6e93208138c
--- /dev/null
+++ b/ext/random/tests/03_randomizer/methods/getInt_expansion_32.phpt
@@ -0,0 +1,25 @@
+--TEST--
+Random: Randomizer: getInt(): Returned values with insufficient bits are correctly expanded
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Randomizer;
+
+final class ByteEngine implements Engine
+{
+    public $count = 0;
+
+    public function generate(): string
+    {
+        return "\x01\x02\x03\x04\x05\x06\x07\x08"[$this->count++];
+    }
+}
+
+$randomizer = new Randomizer(new ByteEngine());
+
+var_dump(bin2hex(pack('V', $randomizer->getInt(0, 0x00FF_FFFF))));
+
+?>
+--EXPECT--
+string(8) "01020300"
diff --git a/ext/random/tests/03_randomizer/methods/getInt_expansion_64.phpt b/ext/random/tests/03_randomizer/methods/getInt_expansion_64.phpt
new file mode 100644
index 00000000000..87c6bfeafeb
--- /dev/null
+++ b/ext/random/tests/03_randomizer/methods/getInt_expansion_64.phpt
@@ -0,0 +1,27 @@
+--TEST--
+Random: Randomizer: getInt(): Returned values with insufficient bits are correctly expanded (64 Bit)
+--SKIPIF--
+<?php if (PHP_INT_SIZE != 8) die("skip 64-bit only"); ?>
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Randomizer;
+
+final class ByteEngine implements Engine
+{
+    public $count = 0;
+
+    public function generate(): string
+    {
+        return "\x01\x02\x03\x04\x05\x06\x07\x08"[$this->count++];
+    }
+}
+
+$randomizer = new Randomizer(new ByteEngine());
+
+var_dump(bin2hex(pack('P', $randomizer->getInt(0, 0x00FF_FFFF_FFFF_FFFF))));
+
+?>
+--EXPECT--
+string(16) "0102030405060700"
diff --git a/ext/random/tests/03_randomizer/gh9415.phpt b/ext/random/tests/03_randomizer/methods/getInt_gh9415.phpt
similarity index 100%
rename from ext/random/tests/03_randomizer/gh9415.phpt
rename to ext/random/tests/03_randomizer/methods/getInt_gh9415.phpt
diff --git a/ext/random/tests/03_randomizer/methods/nextInt.phpt b/ext/random/tests/03_randomizer/methods/nextInt.phpt
new file mode 100644
index 00000000000..fd4460cb811
--- /dev/null
+++ b/ext/random/tests/03_randomizer/methods/nextInt.phpt
@@ -0,0 +1,50 @@
+--TEST--
+Random: Randomizer: nextInt(): Basic functionality
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Engine\Mt19937;
+use Random\Engine\PcgOneseq128XslRr64;
+use Random\Engine\Secure;
+use Random\Engine\Test\TestShaEngine;
+use Random\Engine\Xoshiro256StarStar;
+use Random\Randomizer;
+
+require __DIR__ . "/../../engines.inc";
+
+$engines = [];
+$engines[] = new Mt19937(null, MT_RAND_MT19937);
+$engines[] = new Mt19937(null, MT_RAND_PHP);
+$engines[] = new PcgOneseq128XslRr64();
+$engines[] = new Xoshiro256StarStar();
+$engines[] = new Secure();
+$engines[] = new TestShaEngine();
+
+foreach ($engines as $engine) {
+    echo $engine::class, PHP_EOL;
+
+    $randomizer = new Randomizer($engine);
+
+    for ($i = 0; $i < 10_000; $i++) {
+        try {
+            $randomizer->nextInt();
+        } catch (\Random\RandomException $e) {
+            if ($e->getMessage() !== 'Generated value exceeds size of int' || PHP_INT_SIZE !== 4) {
+                throw $e;
+            }
+        }
+    }
+}
+
+die('success');
+
+?>
+--EXPECT--
+Random\Engine\Mt19937
+Random\Engine\Mt19937
+Random\Engine\PcgOneseq128XslRr64
+Random\Engine\Xoshiro256StarStar
+Random\Engine\Secure
+Random\Engine\Test\TestShaEngine
+success
diff --git a/ext/random/tests/03_randomizer/methods/nextInt_64_engine_on_32_platform.phpt b/ext/random/tests/03_randomizer/methods/nextInt_64_engine_on_32_platform.phpt
new file mode 100644
index 00000000000..2a408e566e0
--- /dev/null
+++ b/ext/random/tests/03_randomizer/methods/nextInt_64_engine_on_32_platform.phpt
@@ -0,0 +1,21 @@
+--TEST--
+Random: Randomizer: nextInt(): Throws for 64 bit engines on 32 bit platforms
+--SKIPIF--
+<?php if (PHP_INT_SIZE == 8) die("skip 32-bit only"); ?>
+--FILE--
+<?php
+
+use Random\Randomizer;
+use Random\Engine\Xoshiro256StarStar;
+
+$randomizer = new Randomizer(new Xoshiro256StarStar());
+
+try {
+    var_dump($randomizer->nextInt());
+} catch (Random\RandomException $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+?>
+--EXPECT--
+Generated value exceeds size of int
diff --git a/ext/random/tests/03_randomizer/methods/pickArrayKeys.phpt b/ext/random/tests/03_randomizer/methods/pickArrayKeys.phpt
new file mode 100644
index 00000000000..4178455898d
--- /dev/null
+++ b/ext/random/tests/03_randomizer/methods/pickArrayKeys.phpt
@@ -0,0 +1,84 @@
+--TEST--
+Random: Randomizer: pickArrayKeys(): Basic functionality
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Engine\Mt19937;
+use Random\Engine\PcgOneseq128XslRr64;
+use Random\Engine\Secure;
+use Random\Engine\Test\TestShaEngine;
+use Random\Engine\Xoshiro256StarStar;
+use Random\Randomizer;
+
+require __DIR__ . "/../../engines.inc";
+
+$engines = [];
+$engines[] = new Mt19937(null, MT_RAND_MT19937);
+$engines[] = new Mt19937(null, MT_RAND_PHP);
+$engines[] = new PcgOneseq128XslRr64();
+$engines[] = new Xoshiro256StarStar();
+$engines[] = new Secure();
+$engines[] = new TestShaEngine();
+
+$array1 = []; // list
+$array2 = []; // associative array with only strings
+$array3 = []; // mixed key array
+for ($i = 0; $i < 500; $i++) {
+    $string = sha1((string)$i);
+
+    $array1[] = $i;
+    $array2[$string] = $i;
+    $array3[$string] = $i;
+    $array3[$i] = $string;
+}
+
+foreach ($engines as $engine) {
+    echo $engine::class, PHP_EOL;
+
+    $randomizer = new Randomizer($engine);
+
+    for ($i = 1; $i < 100; $i++) {
+        $result = $randomizer->pickArrayKeys($array1, $i);
+
+        if (array_unique($result) !== $result) {
+            die("failure: duplicates returned at {$i} for array1");
+        }
+
+        if (array_diff($result, array_keys($array1)) !== []) {
+            die("failure: non-keys returned at {$i} for array1");
+        }
+
+        $result = $randomizer->pickArrayKeys($array2, $i);
+
+        if (array_unique($result) !== $result) {
+            die("failure: duplicates returned at {$i} for array2");
+        }
+
+        if (array_diff($result, array_keys($array2)) !== []) {
+            die("failure: non-keys returned at {$i} for array2");
+        }
+
+        $result = $randomizer->pickArrayKeys($array3, $i);
+
+        if (array_unique($result) !== $result) {
+            die("failure: duplicates returned at {$i} for array3");
+        }
+
+        if (array_diff($result, array_keys($array3)) !== []) {
+            die("failure: non-keys returned at {$i} for array3");
+        }
+    }
+}
+
+die('success');
+
+?>
+--EXPECT--
+Random\Engine\Mt19937
+Random\Engine\Mt19937
+Random\Engine\PcgOneseq128XslRr64
+Random\Engine\Xoshiro256StarStar
+Random\Engine\Secure
+Random\Engine\Test\TestShaEngine
+success
diff --git a/ext/random/tests/03_randomizer/methods/pickArrayKeys_error.phpt b/ext/random/tests/03_randomizer/methods/pickArrayKeys_error.phpt
new file mode 100644
index 00000000000..15526327b09
--- /dev/null
+++ b/ext/random/tests/03_randomizer/methods/pickArrayKeys_error.phpt
@@ -0,0 +1,49 @@
+--TEST--
+Random: Randomizer: pickArrayKeys(): Parameters are correctly validated
+--FILE--
+<?php
+
+use Random\Randomizer;
+
+function randomizer(): Randomizer
+{
+    return new Randomizer();
+}
+
+try {
+    var_dump(randomizer()->pickArrayKeys("foo", 2));
+} catch (TypeError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    var_dump(randomizer()->pickArrayKeys([], 0));
+} catch (ValueError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    var_dump(randomizer()->pickArrayKeys(range(1, 3), 0));
+} catch (ValueError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    var_dump(randomizer()->pickArrayKeys(range(1, 3), -1));
+} catch (ValueError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+    var_dump(randomizer()->pickArrayKeys(range(1, 3), 10));
+} catch (ValueError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+?>
+--EXPECTF--
+Random\Randomizer::pickArrayKeys(): Argument #1 ($array) must be of type array, string given
+Random\Randomizer::pickArrayKeys(): Argument #1 ($array) cannot be empty
+Random\Randomizer::pickArrayKeys(): Argument #2 ($num) must be between 1 and the number of elements in argument #1 ($array)
+Random\Randomizer::pickArrayKeys(): Argument #2 ($num) must be between 1 and the number of elements in argument #1 ($array)
+Random\Randomizer::pickArrayKeys(): Argument #2 ($num) must be between 1 and the number of elements in argument #1 ($array)
diff --git a/ext/random/tests/03_randomizer/methods/shuffleArray.phpt b/ext/random/tests/03_randomizer/methods/shuffleArray.phpt
new file mode 100644
index 00000000000..c0f6d17fecd
--- /dev/null
+++ b/ext/random/tests/03_randomizer/methods/shuffleArray.phpt
@@ -0,0 +1,53 @@
+--TEST--
+Random: Randomizer: shuffleArray(): Basic functionality
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Engine\Mt19937;
+use Random\Engine\PcgOneseq128XslRr64;
+use Random\Engine\Secure;
+use Random\Engine\Test\TestShaEngine;
+use Random\Engine\Xoshiro256StarStar;
+use Random\Randomizer;
+
+require __DIR__ . "/../../engines.inc";
+
+$engines = [];
+$engines[] = new Mt19937(null, MT_RAND_MT19937);
+$engines[] = new Mt19937(null, MT_RAND_PHP);
+$engines[] = new PcgOneseq128XslRr64();
+$engines[] = new Xoshiro256StarStar();
+$engines[] = new Secure();
+$engines[] = new TestShaEngine();
+
+foreach ($engines as $engine) {
+    echo $engine::class, PHP_EOL;
+
+    $randomizer = new Randomizer($engine);
+
+    // This test is slow, test all numbers smaller than 50 and then in steps of 677 (which is prime).
+    for ($i = 1; $i < 5_000; $i += ($i < 50 ? 1 : 677)) {
+        $array = range(1, $i);
+
+        $result = $randomizer->shuffleArray($array);
+
+        sort($result);
+
+        if ($result !== $array) {
+            die("failure: not a permutation at {$i}");
+        }
+    }
+}
+
+die('success');
+
+?>
+--EXPECT--
+Random\Engine\Mt19937
+Random\Engine\Mt19937
+Random\Engine\PcgOneseq128XslRr64
+Random\Engine\Xoshiro256StarStar
+Random\Engine\Secure
+Random\Engine\Test\TestShaEngine
+success
diff --git a/ext/random/tests/03_randomizer/methods/shuffleBytes.phpt b/ext/random/tests/03_randomizer/methods/shuffleBytes.phpt
new file mode 100644
index 00000000000..d16168d32fe
--- /dev/null
+++ b/ext/random/tests/03_randomizer/methods/shuffleBytes.phpt
@@ -0,0 +1,60 @@
+--TEST--
+Random: Randomizer: shuffleBytes(): Basic functionality
+--FILE--
+<?php
+
+use Random\Engine;
+use Random\Engine\Mt19937;
+use Random\Engine\PcgOneseq128XslRr64;
+use Random\Engine\Secure;
+use Random\Engine\Test\TestShaEngine;
+use Random\Engine\Xoshiro256StarStar;
+use Random\Randomizer;
+
+require __DIR__ . "/../../engines.inc";
+
+$engines = [];
+$engines[] = new Mt19937(null, MT_RAND_MT19937);
+$engines[] = new Mt19937(null, MT_RAND_PHP);
+$engines[] = new PcgOneseq128XslRr64();
+$engines[] = new Xoshiro256StarStar();
+$engines[] = new Secure();
+$engines[] = new TestShaEngine();
+
+function sort_bytes(string $bytes): string
+{
+    $bytes = str_split($bytes);
+    sort($bytes);
+    return implode('', $bytes);
+}
+
+foreach ($engines as $engine) {
+    echo $engine::class, PHP_EOL;
+
+    $randomizer = new Randomizer($engine);
+
+    // This test is slow, test all numbers smaller than 50 and then in steps of 677 (which is prime).
+    for ($i = 1; $i < 5_000; $i += ($i < 50 ? 1 : 677)) {
+        $bytes = sort_bytes(random_bytes($i));
+
+        $result = $randomizer->shuffleBytes($bytes);
+
+        $result = sort_bytes($result);
+
+        if ($result !== $bytes) {
+            die("failure: not a permutation at {$i}");
+        }
+    }
+}
+
+die('success');
+
+?>
+--EXPECT--
+Random\Engine\Mt19937
+Random\Engine\Mt19937
+Random\Engine\PcgOneseq128XslRr64
+Random\Engine\Xoshiro256StarStar
+Random\Engine\Secure
+Random\Engine\Test\TestShaEngine
+success
diff --git a/ext/random/tests/03_randomizer/nextint_error.phpt b/ext/random/tests/03_randomizer/nextint_error.phpt
deleted file mode 100644
index 5f9f8bdc77c..00000000000
--- a/ext/random/tests/03_randomizer/nextint_error.phpt
+++ /dev/null
@@ -1,18 +0,0 @@
---TEST--
-Random: Randomizer: nextInt() throws for too large values on 32 Bit
---SKIPIF--
-<?php if (PHP_INT_SIZE == 8) die("skip 32-bit only"); ?>
---FILE--
-<?php
-
-$randomizer = new \Random\Randomizer(new \Random\Engine\Xoshiro256StarStar());
-
-try {
-	var_dump($randomizer->nextInt());
-} catch (\Random\RandomException $e) {
-	echo $e->getMessage(), PHP_EOL;
-}
-
-?>
---EXPECT--
-Generated value exceeds size of int
diff --git a/ext/random/tests/03_randomizer/pick_array_keys_error.phpt b/ext/random/tests/03_randomizer/pick_array_keys_error.phpt
deleted file mode 100644
index 98abc82a550..00000000000
--- a/ext/random/tests/03_randomizer/pick_array_keys_error.phpt
+++ /dev/null
@@ -1,52 +0,0 @@
---TEST--
-Random: Randomizer: pickArrayKeys error pattern
---FILE--
-<?php
-
-try {
-    var_dump((new \Random\Randomizer())->pickArrayKeys([], 0));
-} catch (\ValueError $e) {
-    echo $e->getMessage() . "\n";
-}
-
-try {
-    var_dump((new \Random\Randomizer())->pickArrayKeys(range(1, 3), 0));
-} catch (\ValueError $e) {
-    echo $e->getMessage() . "\n";
-}
-
-try {
-    var_dump((new \Random\Randomizer())->pickArrayKeys(range(1, 3), -1));
-} catch (\ValueError $e) {
-    echo $e->getMessage() . "\n";
-}
-
-try {
-    var_dump((new \Random\Randomizer())->pickArrayKeys(range(1, 3), 10));
-} catch (\ValueError $e) {
-    echo $e->getMessage() . "\n";
-}
-
-var_dump((new \Random\Randomizer())->pickArrayKeys(range(1, 3), 3));
-var_dump((new \Random\Randomizer())->pickArrayKeys(range(1, 3), 2));
-
-?>
---EXPECTF--
-Random\Randomizer::pickArrayKeys(): Argument #1 ($array) cannot be empty
-Random\Randomizer::pickArrayKeys(): Argument #2 ($num) must be between 1 and the number of elements in argument #1 ($array)
-Random\Randomizer::pickArrayKeys(): Argument #2 ($num) must be between 1 and the number of elements in argument #1 ($array)
-Random\Randomizer::pickArrayKeys(): Argument #2 ($num) must be between 1 and the number of elements in argument #1 ($array)
-array(3) {
-  [0]=>
-  int(%d)
-  [1]=>
-  int(%d)
-  [2]=>
-  int(%d)
-}
-array(2) {
-  [0]=>
-  int(%d)
-  [1]=>
-  int(%d)
-}
diff --git a/ext/random/tests/03_randomizer/readonly.phpt b/ext/random/tests/03_randomizer/readonly.phpt
index f1f4a461714..f5cf7cc0dd5 100644
--- a/ext/random/tests/03_randomizer/readonly.phpt
+++ b/ext/random/tests/03_randomizer/readonly.phpt
@@ -1,43 +1,30 @@
 --TEST--
-Random: Randomizer: readonly engine
+Random: Randomizer: The engine property must be readonly
 --FILE--
 <?php
 
-$one = new \Random\Randomizer(
-    new \Random\Engine\PcgOneseq128XslRr64(1234)
-);
+use Random\Engine\PcgOneseq128XslRr64;
+use Random\Engine\Xoshiro256StarStar;
+use Random\Randomizer;
 
-$one_ng_clone = clone $one->engine;
-if ($one->engine->generate() !== $one_ng_clone->generate()) {
-    die('invalid result');
-}
+$randomizer = new Randomizer(new PcgOneseq128XslRr64(1234));
+$referenceRandomizer = new Randomizer(new PcgOneseq128XslRr64(1234));
 
 try {
-    $one->engine = $one_ng_clone;
-} catch (\Throwable $e) {
-    echo $e->getMessage() . PHP_EOL;
+    $randomizer->engine = new Xoshiro256StarStar(1234);
+} catch (Throwable $e) {
+    echo $e->getMessage(), PHP_EOL;
 }
 
-$two = new \Random\Randomizer(
-    new \Random\Engine\Secure()
-);
-
-try {
-    $two_ng_clone = clone $two->engine;
-} catch (\Throwable $e) {
-    echo $e->getMessage() . PHP_EOL;
+for ($i = 0; $i < 10_000; $i++) {
+    if ($randomizer->getInt(0, $i) !== $referenceRandomizer->getInt(0, $i)) {
+        die("failure: state differs at {$i}");
+    }
 }
 
-try {
-    $two->engine = $one_ng_clone;
-} catch (\Throwable $e) {
-    echo $e->getMessage() . PHP_EOL;
-}
+die('success');
 
-die('success')
 ?>
 --EXPECT--
 Cannot modify readonly property Random\Randomizer::$engine
-Trying to clone an uncloneable object of class Random\Engine\Secure
-Cannot modify readonly property Random\Randomizer::$engine
 success
diff --git a/ext/random/tests/03_randomizer/serialize.phpt b/ext/random/tests/03_randomizer/serialize.phpt
index 37841a0db10..b02bb93c827 100644
--- a/ext/random/tests/03_randomizer/serialize.phpt
+++ b/ext/random/tests/03_randomizer/serialize.phpt
@@ -1,57 +1,50 @@
 --TEST--
-Random: Randomizer: serialize
+Random: Randomizer: Serialization of the Randomizer must preserve the sequence
 --FILE--
 <?php
 
+use Random\Engine;
+use Random\Engine\Mt19937;
+use Random\Engine\PcgOneseq128XslRr64;
+use Random\Engine\Test\TestShaEngine;
+use Random\Engine\Xoshiro256StarStar;
+use Random\Randomizer;
+
+require __DIR__ . "/../engines.inc";
+
 $engines = [];
-$engines[] = new \Random\Engine\Mt19937(\random_int(\PHP_INT_MIN, \PHP_INT_MAX), MT_RAND_MT19937);
-$engines[] = new \Random\Engine\Mt19937(\random_int(\PHP_INT_MIN, \PHP_INT_MAX), MT_RAND_PHP);
-$engines[] = new \Random\Engine\PcgOneseq128XslRr64(\random_int(\PHP_INT_MIN, \PHP_INT_MAX));
-$engines[] = new \Random\Engine\Xoshiro256StarStar(\random_int(\PHP_INT_MIN, \PHP_INT_MAX));
-$engines[] = new \Random\Engine\Secure(); 
-$generate = \random_bytes(16);
-$engines[] = new class () implements Random\Engine {
-    public function generate(): string
-    {
-        global $generate;
-        return $generate;
-    }
-};
-class UserEngine implements Random\Engine
-{
-    public function generate(): string
-    {
-        global $generate;
-        return $generate;
-    }
-}
-$engines[] = new UserEngine();
+$engines[] = new Mt19937(1234, MT_RAND_MT19937);
+$engines[] = new Mt19937(1234, MT_RAND_PHP);
+$engines[] = new PcgOneseq128XslRr64(1234);
+$engines[] = new Xoshiro256StarStar(1234);
+$engines[] = new TestShaEngine("1234");
 
 foreach ($engines as $engine) {
-    $randomizer = new Random\Randomizer($engine);
-    $randomizer->getInt(\PHP_INT_MIN, \PHP_INT_MAX);
-    try {
-        $randomizer2 = unserialize(serialize($randomizer));
-    } catch (\Exception $e) {
-        echo $e->getMessage() . PHP_EOL;
-        continue;
+    echo $engine::class, PHP_EOL;
+
+    $randomizer = new Randomizer($engine);
+
+    for ($i = 0; $i < 10_000; $i++) {
+        $randomizer->getInt(0, $i);
     }
 
-    if ($randomizer->getInt(\PHP_INT_MIN, \PHP_INT_MAX) !== $randomizer2->getInt(\PHP_INT_MIN, \PHP_INT_MAX)) {
-        die($engine::class . ': failure.');
-    }
+    $randomizer2 = unserialize(serialize($randomizer));
 
-    echo $engine::class . ': success' . PHP_EOL;
+    for ($i = 0; $i < 10_000; $i++) {
+        if ($randomizer->getInt(0, $i) !== $randomizer2->getInt(0, $i)) {
+            $className = $engine::class;
+
+            die("failure: state differs at {$i}");
+        }
+    }
 }
 
 die('success');
 ?>
---EXPECTF--
-Random\Engine\Mt19937: success
-Random\Engine\Mt19937: success
-Random\Engine\PcgOneseq128XslRr64: success
-Random\Engine\Xoshiro256StarStar: success
-Serialization of 'Random\Engine\Secure' is not allowed
-Serialization of 'Random\Engine@anonymous' is not allowed
-UserEngine: success
+--EXPECT--
+Random\Engine\Mt19937
+Random\Engine\Mt19937
+Random\Engine\PcgOneseq128XslRr64
+Random\Engine\Xoshiro256StarStar
+Random\Engine\Test\TestShaEngine
 success
diff --git a/ext/random/tests/03_randomizer/serialize_disallowed.phpt b/ext/random/tests/03_randomizer/serialize_disallowed.phpt
new file mode 100644
index 00000000000..06f8ea2cb09
--- /dev/null
+++ b/ext/random/tests/03_randomizer/serialize_disallowed.phpt
@@ -0,0 +1,17 @@
+--TEST--
+Random: Randomizer: Serialization of the Randomizer fails if the engine is not serializable
+--FILE--
+<?php
+
+use Random\Engine\Secure;
+use Random\Randomizer;
+
+try {
+    serialize(new Randomizer(new Secure()));
+} catch (Exception $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+?>
+--EXPECT--
+Serialization of 'Random\Engine\Secure' is not allowed
diff --git a/ext/random/tests/03_randomizer/user_exits.phpt b/ext/random/tests/03_randomizer/user_exits.phpt
deleted file mode 100644
index 6d6f5636cbe..00000000000
--- a/ext/random/tests/03_randomizer/user_exits.phpt
+++ /dev/null
@@ -1,19 +0,0 @@
---TEST--
-Random: Randomizer: User: Engine exits
---FILE--
-<?php
-
-$randomizer = (new \Random\Randomizer(
-    new class () implements \Random\Engine {
-        public function generate(): string
-        {
-            exit("Exit\n");
-        }
-    }
-));
-
-var_dump($randomizer->getBytes(1));
-
-?>
---EXPECT--
-Exit
diff --git a/ext/random/tests/03_randomizer/user_throws.phpt b/ext/random/tests/03_randomizer/user_throws.phpt
deleted file mode 100644
index 41cd004b638..00000000000
--- a/ext/random/tests/03_randomizer/user_throws.phpt
+++ /dev/null
@@ -1,24 +0,0 @@
---TEST--
-Random: Randomizer: User: Engine throws
---FILE--
-<?php
-
-$randomizer = (new \Random\Randomizer(
-    new class () implements \Random\Engine {
-        public function generate(): string
-        {
-            throw new Exception('Error');
-        }
-    }
-));
-
-var_dump($randomizer->getBytes(1));
-
-?>
---EXPECTF--
-Fatal error: Uncaught Exception: Error in %s:%d
-Stack trace:
-#0 [internal function]: Random\Engine@anonymous->generate()
-#1 %s(%d): Random\Randomizer->getBytes(1)
-#2 {main}
-  thrown in %s on line %d
diff --git a/ext/random/tests/03_randomizer/user_unsafe.phpt b/ext/random/tests/03_randomizer/user_unsafe.phpt
deleted file mode 100644
index 6e6a8151fdf..00000000000
--- a/ext/random/tests/03_randomizer/user_unsafe.phpt
+++ /dev/null
@@ -1,141 +0,0 @@
---TEST--
-Random: Randomizer: User: Engine unsafe
---FILE--
-<?php
-
-use Random\Randomizer;
-
-final class EmptyStringEngine implements \Random\Engine {
-    public function generate(): string
-    {
-        return '';
-    }
-}
-
-final class HeavilyBiasedEngine implements \Random\Engine {
-    public function generate(): string
-    {
-        return \str_repeat("\xff", PHP_INT_SIZE);
-    }
-}
-
-echo "=====================", PHP_EOL;
-
-foreach ([
-    EmptyStringEngine::class,
-    HeavilyBiasedEngine::class,
-] as $engine) {
-    echo $engine, PHP_EOL, "=====================", PHP_EOL, PHP_EOL;
-
-    try {
-        var_dump((new Randomizer(new $engine()))->getInt(0, 123));
-    } catch (Throwable $e) {
-        echo $e, PHP_EOL;
-    }
-
-    echo PHP_EOL, "-------", PHP_EOL, PHP_EOL;
-
-    try {
-        var_dump((new Randomizer(new $engine()))->nextInt());
-    } catch (Throwable $e) {
-        echo $e, PHP_EOL;
-    }
-
-    echo PHP_EOL, "-------", PHP_EOL, PHP_EOL;
-
-    try {
-        var_dump(bin2hex((new Randomizer(new $engine()))->getBytes(1)));
-    } catch (Throwable $e) {
-        echo $e, PHP_EOL;
-    }
-
-    echo PHP_EOL, "-------", PHP_EOL, PHP_EOL;
-
-    try {
-        var_dump((new Randomizer(new $engine()))->shuffleArray(\range(1, 10)));
-    } catch (Throwable $e) {
-        echo $e, PHP_EOL;
-    }
-
-    echo PHP_EOL, "-------", PHP_EOL, PHP_EOL;
-
-    try {
-        var_dump((new Randomizer(new $engine()))->shuffleBytes('foobar'));
-    } catch (Throwable $e) {
-        echo $e, PHP_EOL;
-    }
-
-    echo PHP_EOL, "=====================", PHP_EOL;
-}
-
-?>
---EXPECTF--
-=====================
-EmptyStringEngine
-=====================
-
-Random\BrokenRandomEngineError: A random engine must return a non-empty string in %s:%d
-Stack trace:
-#0 %s(%d): Random\Randomizer->getInt(0, 123)
-#1 {main}
-
--------
-
-Random\BrokenRandomEngineError: A random engine must return a non-empty string in %s:%d
-Stack trace:
-#0 %s(%d): Random\Randomizer->nextInt()
-#1 {main}
-
--------
-
-Random\BrokenRandomEngineError: A random engine must return a non-empty string in %s:%d
-Stack trace:
-#0 %s(%d): Random\Randomizer->getBytes(1)
-#1 {main}
-
--------
-
-Random\BrokenRandomEngineError: A random engine must return a non-empty string in %s:%d
-Stack trace:
-#0 %s(%d): Random\Randomizer->shuffleArray(Array)
-#1 {main}
-
--------
-
-Random\BrokenRandomEngineError: A random engine must return a non-empty string in %s:%d
-Stack trace:
-#0 %s(%d): Random\Randomizer->shuffleBytes('foobar')
-#1 {main}
-
-=====================
-HeavilyBiasedEngine
-=====================
-
-Random\BrokenRandomEngineError: Failed to generate an acceptable random number in 50 attempts in %s:%d
-Stack trace:
-#0 %s(%d): Random\Randomizer->getInt(0, 123)
-#1 {main}
-
--------
-
-int(%d)
-
--------
-
-string(2) "ff"
-
--------
-
-Random\BrokenRandomEngineError: Failed to generate an acceptable random number in 50 attempts in %s:%d
-Stack trace:
-#0 %s(%d): Random\Randomizer->shuffleArray(Array)
-#1 {main}
-
--------
-
-Random\BrokenRandomEngineError: Failed to generate an acceptable random number in 50 attempts in %s:%d
-Stack trace:
-#0 %s(%d): Random\Randomizer->shuffleBytes('foobar')
-#1 {main}
-
-=====================
diff --git a/ext/random/tests/engines.inc b/ext/random/tests/engines.inc
new file mode 100644
index 00000000000..909f581d775
--- /dev/null
+++ b/ext/random/tests/engines.inc
@@ -0,0 +1,74 @@
+<?php
+
+namespace Random\Engine\Test;
+
+use Random\Engine;
+
+final class TestShaEngine implements Engine
+{
+    private string $state;
+
+    public function __construct(?string $state = null)
+    {
+        if ($state !== null) {
+            $this->state = $state;
+        } else {
+            $this->state = random_bytes(20);
+        }
+    }
+
+    public function generate(): string
+    {
+        $this->state = sha1($this->state, true);
+
+        return substr($this->state, 0, 8);
+    }
+}
+
+final class TestWrapperEngine implements Engine
+{
+    public function __construct(private readonly Engine $engine)
+    {
+    }
+
+    public function generate(): string
+    {
+        return $this->engine->generate();
+    }
+}
+
+final class TestXoshiro128PlusPlusEngine implements Engine
+{
+    public function __construct(
+        private int $s0,
+        private int $s1,
+        private int $s2,
+        private int $s3
+    ) {
+    }
+
+    private static function rotl($x, $k)
+    {
+        return (($x << $k) | ($x >> (32 - $k))) & 0xFFFFFFFF;
+    }
+
+    public function generate(): string
+    {
+        $result = (self::rotl(($this->s0 + $this->s3) & 0xFFFFFFFF, 7) + $this->s0) & 0xFFFFFFFF;
+
+        $t = ($this->s1 << 9)  & 0xFFFFFFFF;
+
+        $this->s2 ^= $this->s0;
+        $this->s3 ^= $this->s1;
+        $this->s1 ^= $this->s2;
+        $this->s0 ^= $this->s3;
+
+        $this->s2 ^= $t;
+
+        $this->s3 = self::rotl($this->s3, 11);
+
+        return pack('V', $result);
+    }
+}
+
+?>