Add mem_size histogram

src/hats_import/catalog/resume_plan.py

@@ -239,15 +239,15 @@ def read_histogram(self, healpix_order, which_histogram: str = "row_count"):
                 aggregate_histogram.add(partial)
 
             file_name = file_io.append_paths_to_pointer(self.tmp_path, histogram_binary_file)
-            with open(file_name, "wb+") as file_handle:
+            with open(str(file_name), "wb+") as file_handle:
                 file_handle.write(aggregate_histogram.full_histogram)
             if self.delete_resume_log_files:
                 file_io.remove_directory(
                     file_io.append_paths_to_pointer(self.tmp_path, histogram_directory),
                     ignore_errors=True,
                 )
 
-        with open(file_name, "rb") as file_handle:
+        with open(str(file_name), "rb") as file_handle:
             full_histogram = frombuffer(file_handle.read(), dtype=np.int64)
 
         if len(full_histogram) != hp.order2npix(healpix_order):

tests/hats_import/catalog/test_map_reduce.py

@@ -13,6 +13,7 @@
 import pyarrow as pa
 import pytest
 from hats.pixel_math.sparse_histogram import SparseHistogram
+from nested_pandas.nestedframe import NestedFrame
 
 import hats_import.catalog.map_reduce as mr
 from hats_import.catalog.file_readers import get_file_reader
@@ -780,9 +781,6 @@ def test_get_mem_size_of_chunk():
 
 def test_get_mem_size_of_chunk_nested():
     """Test the _get_mem_size_of_chunk function with nested data."""
-    pytest.importorskip("nested_pandas")
-    from nested_pandas.nestedframe import NestedFrame  # pylint: disable=import-outside-toplevel
-
     # Create a small DataFrame and nest it
     df = pd.DataFrame(
         {