added test for querying schema descripton

Author: Code-Hex

internal/gqlgen/gqlgen_test.yml

@@ -224,3 +224,23 @@ tests:
         }
       json: |
         {"__type":{"name":"Droid","description":"A mechanical creature in the Star Wars universe."}}
+
+  Schema Document:
+    - name: querying schema description
+      schema: |
+        """This is a simple schema"""
+        schema {
+          query: Simple
+        }
+
+        """This is a simple type"""
+        type Simple {
+          """This is a string field"""
+          string: String
+        }
+      query: |
+        {
+          __schema { description }
+        }
+      json: |
+        {"__schema":{"description":"This is a simple schema"}}