Add API base URL castomization option

tests/UserTest.php

@@ -0,0 +1,22 @@
+<?php declare(strict_types=1);
+
+namespace Sept\OAuth2\Client\Test;
+
+use PHPUnit\Framework\Attributes\CoversMethod;
+use PHPUnit\Framework\TestCase;
+use Sept\OAuth2\Client\Provider\SeptemberFirstUser;
+
+#[CoversMethod(SeptemberFirstUser::class, 'getFirstName')]
+final class UserTest extends TestCase
+{
+    public function testCreate(): void
+    {
+        $name = 'Alex';
+        $user = new SeptemberFirstUser([
+            'personal_name' => [
+                'name' => $name,
+            ],
+        ]);
+        self::assertSame($name, $user->getFirstName());
+    }
+}