test(cuda.core): tidy PDL overlap helper import order and docstring

Author: lijinf2

cuda_core/tests/graph/test_graph_builder.py

@@ -777,6 +777,5 @@ def _assert_programmatic_dependency_edge(graph_definition):
 @skipif_need_cuda_headers
 @requires_module(np, "2.2.5", reason="need numpy 2.2.5+ (numpy GH #28632)")
 def test_pdl_same_stream_primary_secondary_overlap_via_graph(init_cuda):
-    """Same-stream PDL overlap via GraphBuilder stream capture on Hopper+.
-    """
+    """Same-stream PDL overlap via GraphBuilder stream capture on Hopper+."""
     run_pdl_overlap_check(Device(), via_graph=True)

cuda_core/tests/helpers/pdl_kernels.py

@@ -3,10 +3,10 @@
 
 """Shared helpers for Programmatic Dependent Launch overlap tests."""
 
-import helpers
 import numpy as np
 import pytest
 
+import helpers
 from cuda.core import LaunchConfig, LegacyPinnedMemoryResource, Program, ProgramOptions, launch