test case added for GraphQL Query

Author: anikghosh256

tests/GraphQLTest.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace PHPShopify;
+
+class GraphQLTest extends TestResource
+{
+    /**
+     * GraphQLTest constructor.
+     */
+    public function __construct()
+    {
+        parent::__construct();
+    }
+
+    
+    /**
+     * GraphQL Query Test
+     */
+    public function testQuery()
+    {
+        $graphQL = <<<Query
+        query {
+            shop {
+                name
+                primaryDomain {
+                  url
+                  host
+                }
+            }
+        }
+        Query;
+
+        $return = static::$shopify->GraphQL->post($graphQL);
+        
+        $this->assertNotEmpty($return['data']['shop']);
+    }
+
+
+}