print_error: improve coverage

Replicates graphql/graphql-js@84b416f

Author: Cito

README.md

@@ -13,7 +13,7 @@ a query language for APIs created by Facebook.
 [![Code Style](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)
 
 The current version 1.0.5 of GraphQL-core-next is up-to-date with GraphQL.js version
-14.3.1. All parts of the API are covered by an extensive test suite of currently 1877
+14.3.1. All parts of the API are covered by an extensive test suite of currently 1879
 unit tests.
 
 

tests/error/test_print_error.py

@@ -6,6 +6,16 @@
 
 
 def describe_print_error():
+    def prints_an_error_without_location():
+        error = GraphQLError("Error without location")
+        assert print_error(error) == "Error without location"
+
+    def prints_an_error_using_node_without_location():
+        error = GraphQLError(
+            "Error attached to node without location",
+            parse("{ foo }", no_location=True),
+        )
+        assert print_error(error) == "Error attached to node without location"
 
     # noinspection PyArgumentEqualDefault
     def prints_line_numbers_with_correct_padding():