Add support for @OneOf directives in print_schema

Replicates graphql/graphql-js@0b7590f

Author: Cito

src/graphql/utilities/print_schema.py

@@ -214,7 +214,12 @@ def print_input_object(type_: GraphQLInputObjectType) -> str:
         print_description(field, "  ", not i) + "  " + print_input_value(name, field)
         for i, (name, field) in enumerate(type_.fields.items())
     ]
-    return print_description(type_) + f"input {type_.name}" + print_block(fields)
+    return (
+        print_description(type_)
+        + f"input {type_.name}"
+        + (" @oneOf" if type_.is_one_of else "")
+        + print_block(fields)
+    )
 
 
 def print_fields(type_: GraphQLObjectType | GraphQLInterfaceType) -> str:

tests/utilities/test_print_schema.py

@@ -514,6 +514,22 @@ def prints_input_type():
             """
         )
 
+    def prints_input_type_with_one_of_directive():
+        input_type = GraphQLInputObjectType(
+            name="InputType",
+            fields={"int": GraphQLInputField(GraphQLInt)},
+            is_one_of=True,
+        )
+
+        schema = GraphQLSchema(types=[input_type])
+        assert expect_printed_schema(schema) == dedent(
+            """
+            input InputType @oneOf {
+              int: Int
+            }
+            """
+        )
+
     def prints_custom_scalar():
         odd_type = GraphQLScalarType(name="Odd")