From e5be32d6eb880c9563fde2f23cc31b7e449719ec Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 24 Jan 2024 18:14:14 +0100
Subject: [PATCH] bpo-46623: Skip two test_zlib tests on s390x (GH-31096)
Skip test_pair() and test_speech128() of test_zlib on s390x since
they fail if zlib uses the s390x hardware accelerator.
---
Lib/test/test_zlib.py | 32 +++++++++++++++++++
.../2022-02-03-09-45-26.bpo-46623.vxzuhV.rst | 2 ++
2 files changed, 34 insertions(+)
create mode 100644 Misc/NEWS.d/next/Tests/2022-02-03-09-45-26.bpo-46623.vxzuhV.rst
diff --git a/Lib/test/test_zlib.py b/Lib/test/test_zlib.py
index 02509cd..f3654c9 100644
--- a/Lib/test/test_zlib.py
+++ b/Lib/test/test_zlib.py
@@ -2,6 +2,7 @@ import unittest
from test import support
import binascii
import copy
+import os
import pickle
import random
import sys
@@ -16,6 +17,35 @@ requires_Decompress_copy = unittest.skipUnless(
hasattr(zlib.decompressobj(), "copy"),
'requires Decompress.copy()')
+# bpo-46623: On s390x, when a hardware accelerator is used, using different
+# ways to compress data with zlib can produce different compressed data.
+# Simplified test_pair() code:
+#
+# def func1(data):
+# return zlib.compress(data)
+#
+# def func2(data)
+# co = zlib.compressobj()
+# x1 = co.compress(data)
+# x2 = co.flush()
+# return x1 + x2
+#
+# On s390x if zlib uses a hardware accelerator, func1() creates a single
+# "final" compressed block whereas func2() produces 3 compressed blocks (the
+# last one is a final block). On other platforms with no accelerator, func1()
+# and func2() produce the same compressed data made of a single (final)
+# compressed block.
+#
+# Only the compressed data is different, the decompression returns the original
+# data:
+#
+# zlib.decompress(func1(data)) == zlib.decompress(func2(data)) == data
+#
+# Make the assumption that s390x always has an accelerator to simplify the skip
+# condition. Windows doesn't have os.uname() but it doesn't support s390x.
+skip_on_s390x = unittest.skipIf(hasattr(os, 'uname') and os.uname().machine == 's390x',
+ 'skipped on s390x')
+
class VersionTestCase(unittest.TestCase):
@@ -174,6 +204,7 @@ class CompressTestCase(BaseCompressTestCase, unittest.TestCase):
bufsize=zlib.DEF_BUF_SIZE),
HAMLET_SCENE)
+ @skip_on_s390x
def test_speech128(self):
# compress more data
data = HAMLET_SCENE * 128
@@ -225,6 +256,7 @@ class CompressTestCase(BaseCompressTestCase, unittest.TestCase):
class CompressObjectTestCase(BaseCompressTestCase, unittest.TestCase):
# Test compression object
+ @skip_on_s390x
def test_pair(self):
# straightforward compress/decompress objects
datasrc = HAMLET_SCENE * 128
diff --git a/Misc/NEWS.d/next/Tests/2022-02-03-09-45-26.bpo-46623.vxzuhV.rst b/Misc/NEWS.d/next/Tests/2022-02-03-09-45-26.bpo-46623.vxzuhV.rst
new file mode 100644
index 0000000..be085c0
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2022-02-03-09-45-26.bpo-46623.vxzuhV.rst
@@ -0,0 +1,2 @@
+Skip test_pair() and test_speech128() of test_zlib on s390x since they fail
+if zlib uses the s390x hardware accelerator. Patch by Victor Stinner.
--
2.43.0