Tests: remove useless parse_literal & parse_value callbacks

Replicates graphql/graphql-js@f2a0c64

Author: Cito

tests/type/test_definition.py

@@ -95,12 +95,7 @@
 UnionType = GraphQLUnionType("Union", [ObjectType], resolve_type=lambda: None)
 EnumType = GraphQLEnumType("Enum", {"foo": GraphQLEnumValue()})
 InputObjectType = GraphQLInputObjectType("InputObject", {})
-ScalarType = GraphQLScalarType(
-    "Scalar",
-    serialize=lambda: None,
-    parse_value=lambda: None,
-    parse_literal=lambda: None,
-)
+ScalarType = GraphQLScalarType("Scalar", serialize=lambda: None)
 
 
 def schema_with_field_type(type_: GraphQLOutputType) -> GraphQLSchema:

tests/type/test_validation.py

@@ -29,17 +29,7 @@
 from graphql.utilities import build_schema, extend_schema
 
 
-def _get(value):
-    """Return a fixed value"""
-    return lambda *args: value
-
-
-SomeScalarType = GraphQLScalarType(
-    name="SomeScalar",
-    serialize=_get(None),
-    parse_value=_get(None),
-    parse_literal=_get(None),
-)
+SomeScalarType = GraphQLScalarType(name="SomeScalar", serialize=lambda: None)
 
 SomeInterfaceType = GraphQLInterfaceType(
     name="SomeInterface", fields=lambda: {"f": GraphQLField(SomeObjectType)}