Fix bin pack chunk size for tiny target file size

Author: 010Soham

pyiceberg/io/pyarrow.py

@@ -2681,7 +2681,7 @@ def bin_pack_arrow_table(tbl: pa.Table, target_file_size: int) -> Iterator[list[
     from pyiceberg.utils.bin_packing import PackingIterator
 
     avg_row_size_bytes = tbl.nbytes / tbl.num_rows
-    target_rows_per_file = target_file_size // avg_row_size_bytes
+    target_rows_per_file = max(1, int(target_file_size / avg_row_size_bytes))
     batches = tbl.to_batches(max_chunksize=target_rows_per_file)
     bin_packed_record_batches = PackingIterator(
         items=batches,

tests/io/test_pyarrow.py

@@ -2248,6 +2248,12 @@ def test_bin_pack_arrow_table(arrow_table_with_null: pa.Table) -> None:
     assert len(list(bin_packed)) == 5
 
 
+def test_bin_pack_arrow_table_target_size_smaller_than_row(arrow_table_with_null: pa.Table) -> None:
+    bin_packed = list(bin_pack_arrow_table(arrow_table_with_null, target_file_size=1))
+    assert len(bin_packed) == arrow_table_with_null.num_rows
+    assert sum(batch.num_rows for bin_ in bin_packed for batch in bin_) == arrow_table_with_null.num_rows
+
+
 def test_schema_mismatch_type(table_schema_simple: Schema) -> None:
     other_schema = pa.schema(
         (