diff --git a/src/graphql/type/directives.py b/src/graphql/type/directives.py
index 46201d38..d4160300 100644
--- a/src/graphql/type/directives.py
+++ b/src/graphql/type/directives.py
@@ -248,17 +248,17 @@ def assert_directive(directive: Any) -> GraphQLDirective:
     description="Marks an element of a GraphQL schema as no longer supported.",
 )
 
-# Used to provide a URL for specifying the behaviour of custom scalar definitions:
+# Used to provide a URL for specifying the behavior of custom scalar definitions:
 GraphQLSpecifiedByDirective = GraphQLDirective(
     name="specifiedBy",
     locations=[DirectiveLocation.SCALAR],
     args={
         "url": GraphQLArgument(
             GraphQLNonNull(GraphQLString),
-            description="The URL that specifies the behaviour of this scalar.",
+            description="The URL that specifies the behavior of this scalar.",
         )
     },
-    description="Exposes a URL that specifies the behaviour of this scalar.",
+    description="Exposes a URL that specifies the behavior of this scalar.",
 )
 
 # Used to declare an Input Object as a OneOf Input Objects.
diff --git a/tests/utilities/test_build_ast_schema.py b/tests/utilities/test_build_ast_schema.py
index b236025c..d4c2dff9 100644
--- a/tests/utilities/test_build_ast_schema.py
+++ b/tests/utilities/test_build_ast_schema.py
@@ -7,6 +7,7 @@
 from typing import Union
 
 import pytest
+
 from graphql import graphql_sync
 from graphql.language import DocumentNode, InterfaceTypeDefinitionNode, parse, print_ast
 from graphql.type import (
@@ -1139,7 +1140,7 @@ def can_build_invalid_schema():
         assert errors
 
     def do_not_override_standard_types():
-        # Note: not sure it's desired behaviour to just silently ignore override
+        # Note: not sure it's desired behavior to just silently ignore override
         # attempts so just documenting it here.
 
         schema = build_schema(
@@ -1252,7 +1253,7 @@ def can_deep_copy_pickled_schema():
             # check that printing the copied schema gives the same SDL
             assert print_schema(copied) == sdl
 
-    @pytest.mark.slow()
+    @pytest.mark.slow
     def describe_deepcopy_and_pickle_big():  # pragma: no cover
         @pytest.mark.timeout(20)
         def can_deep_copy_big_schema(big_schema_sdl):  # noqa: F811
diff --git a/tests/utilities/test_print_schema.py b/tests/utilities/test_print_schema.py
index 878d0770..0e96bbbc 100644
--- a/tests/utilities/test_print_schema.py
+++ b/tests/utilities/test_print_schema.py
@@ -765,9 +765,9 @@ def prints_introspection_schema():
               reason: String = "No longer supported"
             ) on FIELD_DEFINITION | ARGUMENT_DEFINITION | INPUT_FIELD_DEFINITION | ENUM_VALUE
 
-            """Exposes a URL that specifies the behaviour of this scalar."""
+            """Exposes a URL that specifies the behavior of this scalar."""
             directive @specifiedBy(
-              """The URL that specifies the behaviour of this scalar."""
+              """The URL that specifies the behavior of this scalar."""
               url: String!
             ) on SCALAR