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Merged
merged 1 commit into from
Apr 5, 2023
Merged

Update test_mmap.py from Cpython v3.11.2 #4841

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108 changes: 99 additions & 9 deletions Lib/test/test_mmap.py
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Original file line number Diff line number Diff line change
@@ -1,11 +1,15 @@
from test.support import (requires, _2G, _4G, gc_collect, cpython_only)
from test.support import (
requires, _2G, _4G, gc_collect, cpython_only, is_emscripten
)
from test.support.import_helper import import_module
from test.support.os_helper import TESTFN, unlink
import unittest
import os
import re
import itertools
import random
import socket
import string
import sys
import weakref

Expand All @@ -14,6 +18,16 @@

PAGESIZE = mmap.PAGESIZE

tagname_prefix = f'python_{os.getpid()}_test_mmap'
def random_tagname(length=10):
suffix = ''.join(random.choices(string.ascii_uppercase, k=length))
return f'{tagname_prefix}_{suffix}'

# Python's mmap module dup()s the file descriptor. Emscripten's FS layer
# does not materialize file changes through a dupped fd to a new mmap.
if is_emscripten:
raise unittest.SkipTest("incompatible with Emscripten's mmap emulation.")


class MmapTests(unittest.TestCase):

Expand Down Expand Up @@ -609,21 +623,23 @@ def test_tagname(self):
data1 = b"0123456789"
data2 = b"abcdefghij"
assert len(data1) == len(data2)
tagname1 = random_tagname()
tagname2 = random_tagname()

# Test same tag
m1 = mmap.mmap(-1, len(data1), tagname="foo")
m1 = mmap.mmap(-1, len(data1), tagname=tagname1)
m1[:] = data1
m2 = mmap.mmap(-1, len(data2), tagname="foo")
m2 = mmap.mmap(-1, len(data2), tagname=tagname1)
m2[:] = data2
self.assertEqual(m1[:], data2)
self.assertEqual(m2[:], data2)
m2.close()
m1.close()

# Test different tag
m1 = mmap.mmap(-1, len(data1), tagname="foo")
m1 = mmap.mmap(-1, len(data1), tagname=tagname1)
m1[:] = data1
m2 = mmap.mmap(-1, len(data2), tagname="boo")
m2 = mmap.mmap(-1, len(data2), tagname=tagname2)
m2[:] = data2
self.assertEqual(m1[:], data1)
self.assertEqual(m2[:], data2)
Expand All @@ -634,17 +650,18 @@ def test_tagname(self):
@unittest.skipUnless(os.name == 'nt', 'requires Windows')
def test_sizeof(self):
m1 = mmap.mmap(-1, 100)
tagname = "foo"
tagname = random_tagname()
m2 = mmap.mmap(-1, 100, tagname=tagname)
self.assertEqual(sys.getsizeof(m2),
sys.getsizeof(m1) + len(tagname) + 1)

@unittest.skipUnless(os.name == 'nt', 'requires Windows')
def test_crasher_on_windows(self):
# Should not crash (Issue 1733986)
m = mmap.mmap(-1, 1000, tagname="foo")
tagname = random_tagname()
m = mmap.mmap(-1, 1000, tagname=tagname)
try:
mmap.mmap(-1, 5000, tagname="foo")[:] # same tagname, but larger size
mmap.mmap(-1, 5000, tagname=tagname)[:] # same tagname, but larger size
except:
pass
m.close()
Expand Down Expand Up @@ -707,7 +724,6 @@ def test_write_returning_the_number_of_bytes_written(self):
self.assertEqual(mm.write(b"yz"), 2)
self.assertEqual(mm.write(b"python"), 6)

@unittest.skipIf(os.name == 'nt', 'cannot resize anonymous mmaps on Windows')
def test_resize_past_pos(self):
m = mmap.mmap(-1, 8192)
self.addCleanup(m.close)
Expand Down Expand Up @@ -797,6 +813,80 @@ def test_madvise(self):
self.assertEqual(m.madvise(mmap.MADV_NORMAL, 0, 2), None)
self.assertEqual(m.madvise(mmap.MADV_NORMAL, 0, size), None)

@unittest.skipUnless(os.name == 'nt', 'requires Windows')
def test_resize_up_when_mapped_to_pagefile(self):
"""If the mmap is backed by the pagefile ensure a resize up can happen
and that the original data is still in place
"""
start_size = PAGESIZE
new_size = 2 * start_size
data = bytes(random.getrandbits(8) for _ in range(start_size))

m = mmap.mmap(-1, start_size)
m[:] = data
m.resize(new_size)
self.assertEqual(len(m), new_size)
self.assertEqual(m[:start_size], data[:start_size])

@unittest.skipUnless(os.name == 'nt', 'requires Windows')
def test_resize_down_when_mapped_to_pagefile(self):
"""If the mmap is backed by the pagefile ensure a resize down up can happen
and that a truncated form of the original data is still in place
"""
start_size = PAGESIZE
new_size = start_size // 2
data = bytes(random.getrandbits(8) for _ in range(start_size))

m = mmap.mmap(-1, start_size)
m[:] = data
m.resize(new_size)
self.assertEqual(len(m), new_size)
self.assertEqual(m[:new_size], data[:new_size])

@unittest.skipUnless(os.name == 'nt', 'requires Windows')
def test_resize_fails_if_mapping_held_elsewhere(self):
"""If more than one mapping is held against a named file on Windows, neither
mapping can be resized
"""
start_size = 2 * PAGESIZE
reduced_size = PAGESIZE

f = open(TESTFN, 'wb+')
f.truncate(start_size)
try:
m1 = mmap.mmap(f.fileno(), start_size)
m2 = mmap.mmap(f.fileno(), start_size)
with self.assertRaises(OSError):
m1.resize(reduced_size)
with self.assertRaises(OSError):
m2.resize(reduced_size)
m2.close()
m1.resize(reduced_size)
self.assertEqual(m1.size(), reduced_size)
self.assertEqual(os.stat(f.fileno()).st_size, reduced_size)
finally:
f.close()

@unittest.skipUnless(os.name == 'nt', 'requires Windows')
def test_resize_succeeds_with_error_for_second_named_mapping(self):
"""If a more than one mapping exists of the same name, none of them can
be resized: they'll raise an Exception and leave the original mapping intact
"""
start_size = 2 * PAGESIZE
reduced_size = PAGESIZE
tagname = random_tagname()
data_length = 8
data = bytes(random.getrandbits(8) for _ in range(data_length))

m1 = mmap.mmap(-1, start_size, tagname=tagname)
m2 = mmap.mmap(-1, start_size, tagname=tagname)
m1[:data_length] = data
self.assertEqual(m2[:data_length], data)
with self.assertRaises(OSError):
m1.resize(reduced_size)
self.assertEqual(m1.size(), start_size)
self.assertEqual(m1[:data_length], data)
self.assertEqual(m2[:data_length], data)

class LargeMmapTests(unittest.TestCase):

Expand Down