fix periodicity test

src/pystencils/gpu/periodicity.py

@@ -68,8 +68,8 @@ def get_periodic_boundary_functor(
         )
         kernels.append(ast.compile())
 
-    def functor(pdfs, **_):
+    def functor(field, **_):
         for kernel in kernels:
-            kernel(pdfs=pdfs)
+            kernel(field=field)
 
     return functor

tests/nbackend/kernelcreation/test_gpu.py

@@ -158,7 +158,7 @@ def test_periodicity():
     cpu_result = np.copy(arr_cpu)
     periodic_cpu_kernel(cpu_result)
 
-    periodic_gpu_kernel(pdfs=arr_gpu)
+    periodic_gpu_kernel(arr_gpu)
     gpu_result = arr_gpu.get()
     np.testing.assert_equal(cpu_result, gpu_result)