[GitHub] [arrow] amol- commented on a change in pull request #10717: ARROW-13091: [Python] Add compression_level argument to IpcWriteOptions constructor

[GitBox <gi...@apache.org>]

amol- commented on a change in pull request #10717:
URL: https://github.com/apache/arrow/pull/10717#discussion_r669634388



##########
File path: python/pyarrow/tests/test_ipc.py
##########
@@ -329,6 +329,42 @@ def test_stream_simple_roundtrip(stream_fixture, use_legacy_ipc_format):
         reader.read_next_batch()
 
 
+def test_compression_roundtrip():
+    # The ability to set a seed this way is not present on older versions of
+    # numpy (currently in our python 3.6 CI build).  Some inputs might just
+    # happen to compress the same between the two levels so using seeded
+    # random numbers is neccesary
+    if not hasattr(np.random, 'default_rng'):
+        pytest.skip('Requires newer version of numpy')
+    sink = io.BytesIO()
+    rng = np.random.default_rng(seed=42)
+    values = rng.integers(0, 10, 100000)
+    table = pa.Table.from_arrays([values], names=["values"])
+
+    options = pa.ipc.IpcWriteOptions(compression='zstd', compression_level=1)
+    writer = pa.ipc.RecordBatchFileWriter(sink, table.schema, options=options)

Review comment:
       Not really a major thing, but given that the `RecordBatchFileWriter` can act as a context manager and sometimes people look at the tests to learn how to use things, it might be a good idea to write this in the form of
   
   ```
   with pa.ipc.RecordBatchFileWriter(sink, table.schema, options=options) as writer:
      writer.write_table(table)
   ```




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