refactor: Add RandomString generator class

src/PhpPact/Consumer/Matcher/Generators/RandomString.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace PhpPact\Consumer\Matcher\Generators;
+
+use PhpPact\Consumer\Matcher\Model\GeneratorInterface;
+
+/**
+ * Generates a random alphanumeric string of the provided length
+ */
+class RandomString implements GeneratorInterface
+{
+    public function __construct(private int $size = 10)
+    {
+    }
+
+    /**
+     * @return array<string, string|int>
+     */
+    public function jsonSerialize(): array
+    {
+        return [
+            'size'                => $this->size,
+            'pact:generator:type' => 'RandomString',
+        ];
+    }
+}

tests/PhpPact/Consumer/Matcher/Generators/RandomStringTest.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace PhpPactTest\Consumer\Matcher\Generators;
+
+use PhpPact\Consumer\Matcher\Generators\RandomString;
+use PHPUnit\Framework\TestCase;
+
+class RandomStringTest extends TestCase
+{
+    public function testSerialize(): void
+    {
+        $string = new RandomString(11);
+        $this->assertSame(
+            '{"size":11,"pact:generator:type":"RandomString"}',
+            json_encode($string)
+        );
+    }
+}