Add test for custom ExecutionContext (#6)

Author: Cito

README.md

@@ -13,7 +13,7 @@ a query language for APIs created by Facebook.
 
 The current version 1.0.1 of GraphQL-core-next is up-to-date with GraphQL.js
 version 14.0.2. All parts of the API are covered by an extensive test suite of
-currently 1614 unit tests.
+currently 1615 unit tests.
 
 
 ## Documentation

tests/execution/test_executor.py

@@ -5,7 +5,7 @@
 from pytest import raises, mark
 
 from graphql.error import GraphQLError
-from graphql.execution import execute
+from graphql.execution import execute, ExecutionContext
 from graphql.language import parse, OperationDefinitionNode, FieldNode
 from graphql.type import (
     GraphQLSchema,
@@ -846,3 +846,23 @@ def custom_resolver(_source, info, **_args):
             {"foo": "foo"},
             None,
         )
+
+    def uses_a_custom_execution_context_class():
+        query = parse("{ foo }")
+
+        schema = GraphQLSchema(
+            GraphQLObjectType(
+                "Query",
+                {"foo": GraphQLField(GraphQLString, resolve=lambda *_args: "bar")},
+            )
+        )
+
+        class TestExecutionContext(ExecutionContext):
+            def resolve_field(self, parent_type, source, field_nodes, path):
+                result = super().resolve_field(parent_type, source, field_nodes, path)
+                return result * 2
+
+        assert execute(schema, query, execution_context_class=TestExecutionContext) == (
+            {"foo": "barbar"},
+            None,
+        )