feat(validation): allow Stringable objects in IsString rule (#1029)

Co-authored-by: Wilfried JOnker <[email protected]>

Author: Blurazzle

src/Tempest/Validation/src/Rules/IsString.php

@@ -5,6 +5,7 @@
 namespace Tempest\Validation\Rules;
 
 use Attribute;
+use Stringable;
 use Tempest\Validation\Rule;
 
 #[Attribute]
@@ -21,6 +22,10 @@ public function isValid(mixed $value): bool
             return true;
         }
 
+        if ($value instanceof Stringable) {
+            return true;
+        }
+
         return is_string($value);
     }
 

src/Tempest/Validation/tests/Rules/IsStringTest.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Validation\Tests\Rules;
+
+use PHPUnit\Framework\TestCase;
+use Stringable;
+use Tempest\Validation\Rules\IsString;
+
+/**
+ * @internal
+ */
+final class IsStringTest extends TestCase
+{
+    public function test_valid_non_nullable_string(): void
+    {
+        $rule = new IsString();
+
+        $this->assertTrue($rule->isValid('test string'));
+        $this->assertFalse($rule->isValid(false));
+        $this->assertFalse($rule->isValid([]));
+        $this->assertSame('Value should be a string', $rule->message());
+    }
+
+    public function test_valid_nullable_string(): void
+    {
+        $rule = new IsString(orNull: true);
+
+        $this->assertTrue($rule->isValid('test string'));
+        $this->assertTrue($rule->isValid(null));
+        $this->assertFalse($rule->isValid(false));
+        $this->assertFalse($rule->isValid([]));
+    }
+
+    public function test_valid_stringable_object(): void
+    {
+        $rule = new IsString();
+
+        $stringable_object = new class implements Stringable {
+            public function __toString(): string
+            {
+                return 'stringable object';
+            }
+        };
+
+        $this->assertTrue($rule->isValid($stringable_object));
+    }
+}