Viewing file:  test_bufio.py (1.94 KB) -rw-r--r--
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from test.test_support import verify, TestFailed, TESTFN
# Simple test to ensure that optimizations in fileobject.c deliver
# the expected results. For best testing, run this under a debug-build
# Python too (to exercise asserts in the C code).
# Repeat string 'pattern' as often as needed to reach total length
# 'length'. Then call try_one with that string, a string one larger
# than that, and a string one smaller than that. The main driver
# feeds this all small sizes and various powers of 2, so we exercise
# all likely stdio buffer sizes, and "off by one" errors on both
# sides.
def drive_one(pattern, length):
q, r = divmod(length, len(pattern))
teststring = pattern * q + pattern[:r]
verify(len(teststring) == length)
try_one(teststring)
try_one(teststring + "x")
try_one(teststring[:-1])
# Write s + "\n" + s to file, then open it and ensure that successive
# .readline()s deliver what we wrote.
def try_one(s):
# Since C doesn't guarantee we can write/read arbitrary bytes in text
# files, use binary mode.
f = open(TESTFN, "wb")
# write once with \n and once without
f.write(s)
f.write("\n")
f.write(s)
f.close()
f = open(TESTFN, "rb")
line = f.readline()
if line != s + "\n":
raise TestFailed("Expected %r got %r" % (s + "\n", line))
line = f.readline()
if line != s:
raise TestFailed("Expected %r got %r" % (s, line))
line = f.readline()
if line:
raise TestFailed("Expected EOF but got %r" % line)
f.close()
# A pattern with prime length, to avoid simple relationships with
# stdio buffer sizes.
primepat = "1234567890\00\01\02\03\04\05\06"
nullpat = "\0" * 1000
try:
for size in range(1, 257) + [512, 1000, 1024, 2048, 4096, 8192, 10000,
16384, 32768, 65536, 1000000]:
drive_one(primepat, size)
drive_one(nullpat, size)
finally:
try:
import os
os.unlink(TESTFN)
except:
pass
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