Add upstream test

Author: Pavlusha311245

tests/Unit/UpstreamTest.php

@@ -0,0 +1,10 @@
+<?php
+
+use UnitPhpSdk\Config\Upstream;
+
+test('Upstream object can be created', function () {
+    $upstream = new Upstream('test');
+    $upstream->setServer('127.0.0.1');
+
+    expect($upstream)->toBeObject();
+});