tests: add test unit

Author: yangchenzhuo

src/Transport/Adapter/Guzzle.php

@@ -40,7 +40,10 @@ public function setConfig(ClientInterface $client, array $config, array $clientO
             }
         }
         /** @var Client $client */
-        $clientOptions = array_merge($clientOptions, $client->getConfig());
+        if(method_exists($client, 'getConfig')){
+            $clientOptions = array_merge($clientOptions, $client->getConfig());
+        }
+
         $class = get_class($client);
 
         return new $class(array_merge($clientOptions, $guzzleConfig));

tests/Transport/Adapter/GuzzleTest.php

@@ -17,6 +17,7 @@
 use Elastic\Elasticsearch\Transport\Adapter\Guzzle;
 use Elastic\Elasticsearch\Transport\RequestOptions;
 use GuzzleHttp\Client;
+use GuzzleHttp\HandlerStack;
 use GuzzleHttp\RequestOptions As GuzzleOptions;
 use PHPUnit\Framework\TestCase;
 use Psr\Http\Client\ClientInterface;
@@ -65,4 +66,11 @@ public function testSetConfigWithSslCa()
         $this->assertInstanceOf(Client::class, $result);
         $this->assertEquals('test', $result->getConfig(GuzzleOptions::VERIFY));
     }
+
+    public function testSetConfigButNotOverwrittenClientOptions()
+    {
+        $result = $this->guzzleAdapter->setConfig(new Client(['base_uri' => 'http://localhost:12345']), [ RequestOptions::SSL_CA => 'test'], []);
+        $this->assertInstanceOf(Client::class, $result);
+        $this->assertEquals('http://localhost:12345', $result->getConfig('base_uri'));
+    }
 }