build_ast_schema: test building of empty types

Replicates graphql/graphql-js@9cf372f

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 1.0.2 of GraphQL-core-next is up-to-date with GraphQL.js version
-14.1.1. All parts of the API are covered by an extensive test suite of currently 1726
+14.1.1. All parts of the API are covered by an extensive test suite of currently 1731
 unit tests.
 
 

tests/utilities/test_build_ast_schema.py

@@ -74,6 +74,14 @@ def add(self, _info, x, y):
             None,
         )
 
+    def empty_type():
+        sdl = dedent(
+            """
+            type EmptyType
+            """
+        )
+        assert cycle_sdl(sdl) == sdl
+
     def simple_type():
         sdl = dedent(
             """
@@ -266,6 +274,14 @@ def simple_type_with_multiple_arguments():
         )
         assert cycle_sdl(sdl) == sdl
 
+    def empty_interface():
+        sdl = dedent(
+            """
+            interface EmptyInterface
+            """
+        )
+        assert cycle_sdl(sdl) == sdl
+
     def simple_type_with_interface():
         sdl = dedent(
             """
@@ -280,6 +296,14 @@ def simple_type_with_interface():
         )
         assert cycle_sdl(sdl) == sdl
 
+    def empty_enum():
+        sdl = dedent(
+            """
+            enum EmptyEnum
+            """
+        )
+        assert cycle_sdl(sdl) == sdl
+
     def simple_output_enum():
         sdl = dedent(
             """
@@ -323,6 +347,14 @@ def multiple_value_enum():
         )
         assert cycle_sdl(sdl) == sdl
 
+    def empty_union():
+        sdl = dedent(
+            """
+            union EmptyUnion
+            """
+        )
+        assert cycle_sdl(sdl) == sdl
+
     def simple_union():
         sdl = dedent(
             """
@@ -522,7 +554,15 @@ def custom_scalar():
         )
         assert cycle_sdl(sdl) == sdl
 
-    def input_object():
+    def empty_input_object():
+        sdl = dedent(
+            """
+            input EmptyInputObject
+            """
+        )
+        assert cycle_sdl(sdl) == sdl
+
+    def simple_input_object():
         sdl = dedent(
             """
             input Input {