cpython/Lib/test/test_mmap.py
Tim Peters e12cda9840 test_mmap started breaking on Windows, only when run after test_bsddb.
On Win2K it thought 'foo' started at byte offset 0 instead of at the
pagesize, and on Win98 it thought 'foo' didn't exist at all.  Somehow
or other this is related to the new "in memory file" gimmicks in
bsddb, but the old bsddb we use on Windows sucks so bad anyway I don't
want to bother digging deeper.  Flushing the file in test_mmap after
writing to it makes the problem go away, so good enough.
2002-04-23 23:07:28 +00:00

277 lines
8.4 KiB
Python

from test_support import verify, vereq, TESTFN
import mmap
import os, re
PAGESIZE = mmap.PAGESIZE
def test_both():
"Test mmap module on Unix systems and Windows"
# Create a file to be mmap'ed.
if os.path.exists(TESTFN):
os.unlink(TESTFN)
f = open(TESTFN, 'w+')
try: # unlink TESTFN no matter what
# Write 2 pages worth of data to the file
f.write('\0'* PAGESIZE)
f.write('foo')
f.write('\0'* (PAGESIZE-3) )
f.flush()
m = mmap.mmap(f.fileno(), 2 * PAGESIZE)
f.close()
# Simple sanity checks
print type(m) # SF bug 128713: segfaulted on Linux
print ' Position of foo:', m.find('foo') / float(PAGESIZE), 'pages'
vereq(m.find('foo'), PAGESIZE)
print ' Length of file:', len(m) / float(PAGESIZE), 'pages'
vereq(len(m), 2*PAGESIZE)
print ' Contents of byte 0:', repr(m[0])
vereq(m[0], '\0')
print ' Contents of first 3 bytes:', repr(m[0:3])
vereq(m[0:3], '\0\0\0')
# Modify the file's content
print "\n Modifying file's content..."
m[0] = '3'
m[PAGESIZE +3: PAGESIZE +3+3] = 'bar'
# Check that the modification worked
print ' Contents of byte 0:', repr(m[0])
vereq(m[0], '3')
print ' Contents of first 3 bytes:', repr(m[0:3])
vereq(m[0:3], '3\0\0')
print ' Contents of second page:', repr(m[PAGESIZE-1 : PAGESIZE + 7])
vereq(m[PAGESIZE-1 : PAGESIZE + 7], '\0foobar\0')
m.flush()
# Test doing a regular expression match in an mmap'ed file
match = re.search('[A-Za-z]+', m)
if match is None:
print ' ERROR: regex match on mmap failed!'
else:
start, end = match.span(0)
length = end - start
print ' Regex match on mmap (page start, length of match):',
print start / float(PAGESIZE), length
vereq(start, PAGESIZE)
vereq(end, PAGESIZE + 6)
# test seeking around (try to overflow the seek implementation)
m.seek(0,0)
print ' Seek to zeroth byte'
vereq(m.tell(), 0)
m.seek(42,1)
print ' Seek to 42nd byte'
vereq(m.tell(), 42)
m.seek(0,2)
print ' Seek to last byte'
vereq(m.tell(), len(m))
print ' Try to seek to negative position...'
try:
m.seek(-1)
except ValueError:
pass
else:
verify(0, 'expected a ValueError but did not get it')
print ' Try to seek beyond end of mmap...'
try:
m.seek(1,2)
except ValueError:
pass
else:
verify(0, 'expected a ValueError but did not get it')
print ' Try to seek to negative position...'
try:
m.seek(-len(m)-1,2)
except ValueError:
pass
else:
verify(0, 'expected a ValueError but did not get it')
# Try resizing map
print ' Attempting resize()'
try:
m.resize( 512 )
except SystemError:
# resize() not supported
# No messages are printed, since the output of this test suite
# would then be different across platforms.
pass
else:
# resize() is supported
verify(len(m) == 512,
"len(m) is %d, but expecting 512" % (len(m),) )
# Check that we can no longer seek beyond the new size.
try:
m.seek(513,0)
except ValueError:
pass
else:
verify(0, 'Could seek beyond the new size')
m.close()
finally:
try:
f.close()
except OSError:
pass
try:
os.unlink(TESTFN)
except OSError:
pass
# Test for "access" keyword parameter
try:
mapsize = 10
print " Creating", mapsize, "byte test data file."
open(TESTFN, "wb").write("a"*mapsize)
print " Opening mmap with access=ACCESS_READ"
f = open(TESTFN, "rb")
m = mmap.mmap(f.fileno(), mapsize, access=mmap.ACCESS_READ)
verify(m[:] == 'a'*mapsize, "Readonly memory map data incorrect.")
print " Ensuring that readonly mmap can't be slice assigned."
try:
m[:] = 'b'*mapsize
except TypeError:
pass
else:
verify(0, "Able to write to readonly memory map")
print " Ensuring that readonly mmap can't be item assigned."
try:
m[0] = 'b'
except TypeError:
pass
else:
verify(0, "Able to write to readonly memory map")
print " Ensuring that readonly mmap can't be write() to."
try:
m.seek(0,0)
m.write('abc')
except TypeError:
pass
else:
verify(0, "Able to write to readonly memory map")
print " Ensuring that readonly mmap can't be write_byte() to."
try:
m.seek(0,0)
m.write_byte('d')
except TypeError:
pass
else:
verify(0, "Able to write to readonly memory map")
print " Ensuring that readonly mmap can't be resized."
try:
m.resize(2*mapsize)
except SystemError: # resize is not universally supported
pass
except TypeError:
pass
else:
verify(0, "Able to resize readonly memory map")
del m, f
verify(open(TESTFN, "rb").read() == 'a'*mapsize,
"Readonly memory map data file was modified")
print " Opening mmap with access=ACCESS_WRITE"
f = open(TESTFN, "r+b")
m = mmap.mmap(f.fileno(), mapsize, access=mmap.ACCESS_WRITE)
print " Modifying write-through memory map."
m[:] = 'c'*mapsize
verify(m[:] == 'c'*mapsize,
"Write-through memory map memory not updated properly.")
m.flush()
del m, f
verify(open(TESTFN).read() == 'c'*mapsize,
"Write-through memory map data file not updated properly.")
print " Opening mmap with access=ACCESS_COPY"
f = open(TESTFN, "r+b")
m = mmap.mmap(f.fileno(), mapsize, access=mmap.ACCESS_COPY)
print " Modifying copy-on-write memory map."
m[:] = 'd'*mapsize
verify(m[:] == 'd' * mapsize,
"Copy-on-write memory map data not written correctly.")
m.flush()
verify(open(TESTFN, "rb").read() == 'c'*mapsize,
"Copy-on-write test data file should not be modified.")
try:
print " Ensuring copy-on-write maps cannot be resized."
m.resize(2*mapsize)
except TypeError:
pass
else:
verify(0, "Copy-on-write mmap resize did not raise exception.")
del m, f
try:
print " Ensuring invalid access parameter raises exception."
f = open(TESTFN, "r+b")
m = mmap.mmap(f.fileno(), mapsize, access=4)
except ValueError:
pass
else:
verify(0, "Invalid access code should have raised exception.")
if os.name == "posix":
# Try incompatible flags, prot and access parameters.
f = open(TESTFN, "r+b")
try:
m = mmap.mmap(f.fileno(), mapsize, flags=mmap.MAP_PRIVATE,
prot=mmap.PROT_READ, access=mmap.ACCESS_WRITE)
except ValueError:
pass
else:
verify(0, "Incompatible parameters should raise ValueError.")
f.close()
finally:
try:
os.unlink(TESTFN)
except OSError:
pass
# Do a tougher .find() test. SF bug 515943 pointed out that, in 2.2,
# searching for data with embedded \0 bytes didn't work.
f = open(TESTFN, 'w+')
try: # unlink TESTFN no matter what
data = 'aabaac\x00deef\x00\x00aa\x00'
n = len(data)
f.write(data)
f.flush()
m = mmap.mmap(f.fileno(), n)
f.close()
for start in range(n+1):
for finish in range(start, n+1):
slice = data[start : finish]
vereq(m.find(slice), data.find(slice))
vereq(m.find(slice + 'x'), -1)
finally:
try:
os.unlink(TESTFN)
except OSError:
pass
print ' Test passed'
test_both()