Move pandas_udf functions into the tests functions

[tgravescs]

Move pandas_udf functions into the tests functions so they don't try to compile when skipped.

Fixes #922

Note I can now run tests without this failing, but I haven't run the test to make sure it passes as I don't have the env setup to do it.

[tgravescs]

@firestarman @shotai any chance you have env setup you can make sure the test still works when config specified?

[tgravescs]

build

[firestarman]

Thanks a lot for finding this.

One little issue is the two udfs _sum_cpu_func and _sum_gpu_func should be defined again in test tet_window since this test also uses these 2 udfs.

Something like: firestarman@900a91d

@cudf_udf
def test_window(enable_cudf_udf):
+    @pandas_udf("int")
+    def _sum_cpu_func(v: pd.Series) -> int:
+        return v.sum()
+
+   @pandas_udf("integer")
+   def _sum_gpu_func(v: pd.Series) -> int:
+       import cudf
+       gpu_series = cudf.Series(v)
+       return gpu_series.sum()
+
    def cpu_run(spark):
          df = _create_df(spark)
          w = Window.partitionBy('id').rowsBetween(Window.unboundedPreceding, Window.unboundedFollowing)
          return df.withColumn('sum_v', _sum_cpu_func('v').over(w)).collect()

[firestarman]

With the change above, i can get cudf udf tests passed locally.
========== 11 passed, 3418 deselected, 1 warning in 131.68s (0:02:11) ==========

[tgravescs]

@firestarman thanks for the review, I added them to test_window. I realize this duplicates the functions so if there is a better way you can come up with not to duplicate the functions that is more ideal. I tried putting them in a class but that still compiled it.
I think this pr will work for now though.

[tgravescs]

build

[tgravescs]

build