Update PHP client default value (#417)

* update php default value

* update php samples with oas3

samples/client/petstore/php/OpenAPIClient-php/tests/UserApiTest.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace OpenAPI\Client;
+
+use OpenAPI\Client\Api\UserApi;
+
+class UserApiTest extends \PHPUnit_Framework_TestCase
+{
+
+    /** @var UserApi*/
+    private $api;
+
+    public function setUp()
+    {
+        $this->api = new Api\UserApi();
+    }
+
+    // test login use
+    public function testLoginUser()
+    {
+        // initialize the API client
+        // login
+        $response = $this->api->loginUser('xxxxx', 'yyyyyyyy');
+        
+        $this->assertInternalType('string', $response);
+        $this->assertRegExp(
+            '/^logged in user session/',
+            $response,
+            "response string starts with 'logged in user session'"
+        );
+    }
+}