Python code coverage for Lib/test/test_largefile.py

#	count	content
1	n/a	"""Test largefile support on system where this makes sense.
2	n/a	"""
3	n/a
4	n/a	import os
5	n/a	import stat
6	n/a	import sys
7	n/a	import unittest
8	n/a	from test.support import TESTFN, requires, unlink
9	n/a	import io # C implementation of io
10	n/a	import _pyio as pyio # Python implementation of io
11	n/a
12	n/a	# size of file to create (>2GB; 2GB == 2147483648 bytes)
13	n/a	size = 2500000000
14	n/a
15	n/a	class LargeFileTest:
16	n/a	"""Test that each file function works as expected for large
17	n/a	(i.e. > 2GB) files.
18	n/a	"""
19	n/a
20	n/a	def setUp(self):
21	n/a	if os.path.exists(TESTFN):
22	n/a	mode = 'r+b'
23	n/a	else:
24	n/a	mode = 'w+b'
25	n/a
26	n/a	with self.open(TESTFN, mode) as f:
27	n/a	current_size = os.fstat(f.fileno())[stat.ST_SIZE]
28	n/a	if current_size == size+1:
29	n/a	return
30	n/a
31	n/a	if current_size == 0:
32	n/a	f.write(b'z')
33	n/a
34	n/a	f.seek(0)
35	n/a	f.seek(size)
36	n/a	f.write(b'a')
37	n/a	f.flush()
38	n/a	self.assertEqual(os.fstat(f.fileno())[stat.ST_SIZE], size+1)
39	n/a
40	n/a	@classmethod
41	n/a	def tearDownClass(cls):
42	n/a	with cls.open(TESTFN, 'wb'):
43	n/a	pass
44	n/a	if not os.stat(TESTFN)[stat.ST_SIZE] == 0:
45	n/a	raise cls.failureException('File was not truncated by opening '
46	n/a	'with mode "wb"')
47	n/a
48	n/a	def test_osstat(self):
49	n/a	self.assertEqual(os.stat(TESTFN)[stat.ST_SIZE], size+1)
50	n/a
51	n/a	def test_seek_read(self):
52	n/a	with self.open(TESTFN, 'rb') as f:
53	n/a	self.assertEqual(f.tell(), 0)
54	n/a	self.assertEqual(f.read(1), b'z')
55	n/a	self.assertEqual(f.tell(), 1)
56	n/a	f.seek(0)
57	n/a	self.assertEqual(f.tell(), 0)
58	n/a	f.seek(0, 0)
59	n/a	self.assertEqual(f.tell(), 0)
60	n/a	f.seek(42)
61	n/a	self.assertEqual(f.tell(), 42)
62	n/a	f.seek(42, 0)
63	n/a	self.assertEqual(f.tell(), 42)
64	n/a	f.seek(42, 1)
65	n/a	self.assertEqual(f.tell(), 84)
66	n/a	f.seek(0, 1)
67	n/a	self.assertEqual(f.tell(), 84)
68	n/a	f.seek(0, 2) # seek from the end
69	n/a	self.assertEqual(f.tell(), size + 1 + 0)
70	n/a	f.seek(-10, 2)
71	n/a	self.assertEqual(f.tell(), size + 1 - 10)
72	n/a	f.seek(-size-1, 2)
73	n/a	self.assertEqual(f.tell(), 0)
74	n/a	f.seek(size)
75	n/a	self.assertEqual(f.tell(), size)
76	n/a	# the 'a' that was written at the end of file above
77	n/a	self.assertEqual(f.read(1), b'a')
78	n/a	f.seek(-size-1, 1)
79	n/a	self.assertEqual(f.read(1), b'z')
80	n/a	self.assertEqual(f.tell(), 1)
81	n/a
82	n/a	def test_lseek(self):
83	n/a	with self.open(TESTFN, 'rb') as f:
84	n/a	self.assertEqual(os.lseek(f.fileno(), 0, 0), 0)
85	n/a	self.assertEqual(os.lseek(f.fileno(), 42, 0), 42)
86	n/a	self.assertEqual(os.lseek(f.fileno(), 42, 1), 84)
87	n/a	self.assertEqual(os.lseek(f.fileno(), 0, 1), 84)
88	n/a	self.assertEqual(os.lseek(f.fileno(), 0, 2), size+1+0)
89	n/a	self.assertEqual(os.lseek(f.fileno(), -10, 2), size+1-10)
90	n/a	self.assertEqual(os.lseek(f.fileno(), -size-1, 2), 0)
91	n/a	self.assertEqual(os.lseek(f.fileno(), size, 0), size)
92	n/a	# the 'a' that was written at the end of file above
93	n/a	self.assertEqual(f.read(1), b'a')
94	n/a
95	n/a	def test_truncate(self):
96	n/a	with self.open(TESTFN, 'r+b') as f:
97	n/a	if not hasattr(f, 'truncate'):
98	n/a	raise unittest.SkipTest("open().truncate() not available "
99	n/a	"on this system")
100	n/a	f.seek(0, 2)
101	n/a	# else we've lost track of the true size
102	n/a	self.assertEqual(f.tell(), size+1)
103	n/a	# Cut it back via seek + truncate with no argument.
104	n/a	newsize = size - 10
105	n/a	f.seek(newsize)
106	n/a	f.truncate()
107	n/a	self.assertEqual(f.tell(), newsize) # else pointer moved
108	n/a	f.seek(0, 2)
109	n/a	self.assertEqual(f.tell(), newsize) # else wasn't truncated
110	n/a	# Ensure that truncate(smaller than true size) shrinks
111	n/a	# the file.
112	n/a	newsize -= 1
113	n/a	f.seek(42)
114	n/a	f.truncate(newsize)
115	n/a	self.assertEqual(f.tell(), 42)
116	n/a	f.seek(0, 2)
117	n/a	self.assertEqual(f.tell(), newsize)
118	n/a	# XXX truncate(larger than true size) is ill-defined
119	n/a	# across platform; cut it waaaaay back
120	n/a	f.seek(0)
121	n/a	f.truncate(1)
122	n/a	self.assertEqual(f.tell(), 0) # else pointer moved
123	n/a	f.seek(0)
124	n/a	self.assertEqual(len(f.read()), 1) # else wasn't truncated
125	n/a
126	n/a	def test_seekable(self):
127	n/a	# Issue #5016; seekable() can return False when the current position
128	n/a	# is negative when truncated to an int.
129	n/a	for pos in (231-1, 231, 2**31+1):
130	n/a	with self.open(TESTFN, 'rb') as f:
131	n/a	f.seek(pos)
132	n/a	self.assertTrue(f.seekable())
133	n/a
134	n/a	def setUpModule():
135	n/a	try:
136	n/a	import signal
137	n/a	# The default handler for SIGXFSZ is to abort the process.
138	n/a	# By ignoring it, system calls exceeding the file size resource
139	n/a	# limit will raise OSError instead of crashing the interpreter.
140	n/a	signal.signal(signal.SIGXFSZ, signal.SIG_IGN)
141	n/a	except (ImportError, AttributeError):
142	n/a	pass
143	n/a
144	n/a	# On Windows and Mac OSX this test comsumes large resources; It
145	n/a	# takes a long time to build the >2GB file and takes >2GB of disk
146	n/a	# space therefore the resource must be enabled to run this test.
147	n/a	# If not, nothing after this line stanza will be executed.
148	n/a	if sys.platform[:3] == 'win' or sys.platform == 'darwin':
149	n/a	requires('largefile',
150	n/a	'test requires %s bytes and a long time to run' % str(size))
151	n/a	else:
152	n/a	# Only run if the current filesystem supports large files.
153	n/a	# (Skip this test on Windows, since we now always support
154	n/a	# large files.)
155	n/a	f = open(TESTFN, 'wb', buffering=0)
156	n/a	try:
157	n/a	# 2**31 == 2147483648
158	n/a	f.seek(2147483649)
159	n/a	# Seeking is not enough of a test: you must write and flush, too!
160	n/a	f.write(b'x')
161	n/a	f.flush()
162	n/a	except (OSError, OverflowError):
163	n/a	raise unittest.SkipTest("filesystem does not have "
164	n/a	"largefile support")
165	n/a	finally:
166	n/a	f.close()
167	n/a	unlink(TESTFN)
168	n/a
169	n/a
170	n/a	class CLargeFileTest(LargeFileTest, unittest.TestCase):
171	n/a	open = staticmethod(io.open)
172	n/a
173	n/a	class PyLargeFileTest(LargeFileTest, unittest.TestCase):
174	n/a	open = staticmethod(pyio.open)
175	n/a
176	n/a	def tearDownModule():
177	n/a	unlink(TESTFN)
178	n/a
179	n/a	if __name__ == '__main__':
180	n/a	unittest.main()