| """Test largefile support on system where this makes sense. |
| """ |
| |
| import os |
| import stat |
| import sys |
| import unittest |
| from test.test_support import run_unittest, TESTFN, verbose, requires, \ |
| TestSkipped, unlink |
| |
| try: |
| import signal |
| # The default handler for SIGXFSZ is to abort the process. |
| # By ignoring it, system calls exceeding the file size resource |
| # limit will raise IOError instead of crashing the interpreter. |
| oldhandler = signal.signal(signal.SIGXFSZ, signal.SIG_IGN) |
| except (ImportError, AttributeError): |
| pass |
| |
| # create >2GB file (2GB = 2147483648 bytes) |
| size = 2500000000L |
| |
| |
| class TestCase(unittest.TestCase): |
| """Test that each file function works as expected for a large |
| (i.e. > 2GB, do we have to check > 4GB) files. |
| |
| NOTE: the order of execution of the test methods is important! test_seek |
| must run first to create the test file. File cleanup must also be handled |
| outside the test instances because of this. |
| |
| """ |
| |
| def test_seek(self): |
| if verbose: |
| print 'create large file via seek (may be sparse file) ...' |
| with open(TESTFN, 'wb') as f: |
| f.write('z') |
| f.seek(0) |
| f.seek(size) |
| f.write('a') |
| f.flush() |
| if verbose: |
| print 'check file size with os.fstat' |
| self.assertEqual(os.fstat(f.fileno())[stat.ST_SIZE], size+1) |
| |
| def test_osstat(self): |
| if verbose: |
| print 'check file size with os.stat' |
| self.assertEqual(os.stat(TESTFN)[stat.ST_SIZE], size+1) |
| |
| def test_seek_read(self): |
| if verbose: |
| print 'play around with seek() and read() with the built largefile' |
| with open(TESTFN, 'rb') as f: |
| self.assertEqual(f.tell(), 0) |
| self.assertEqual(f.read(1), 'z') |
| self.assertEqual(f.tell(), 1) |
| f.seek(0) |
| self.assertEqual(f.tell(), 0) |
| f.seek(0, 0) |
| self.assertEqual(f.tell(), 0) |
| f.seek(42) |
| self.assertEqual(f.tell(), 42) |
| f.seek(42, 0) |
| self.assertEqual(f.tell(), 42) |
| f.seek(42, 1) |
| self.assertEqual(f.tell(), 84) |
| f.seek(0, 1) |
| self.assertEqual(f.tell(), 84) |
| f.seek(0, 2) # seek from the end |
| self.assertEqual(f.tell(), size + 1 + 0) |
| f.seek(-10, 2) |
| self.assertEqual(f.tell(), size + 1 - 10) |
| f.seek(-size-1, 2) |
| self.assertEqual(f.tell(), 0) |
| f.seek(size) |
| self.assertEqual(f.tell(), size) |
| # the 'a' that was written at the end of file above |
| self.assertEqual(f.read(1), 'a') |
| f.seek(-size-1, 1) |
| self.assertEqual(f.read(1), 'z') |
| self.assertEqual(f.tell(), 1) |
| |
| def test_lseek(self): |
| if verbose: |
| print 'play around with os.lseek() with the built largefile' |
| with open(TESTFN, 'rb') as f: |
| self.assertEqual(os.lseek(f.fileno(), 0, 0), 0) |
| self.assertEqual(os.lseek(f.fileno(), 42, 0), 42) |
| self.assertEqual(os.lseek(f.fileno(), 42, 1), 84) |
| self.assertEqual(os.lseek(f.fileno(), 0, 1), 84) |
| self.assertEqual(os.lseek(f.fileno(), 0, 2), size+1+0) |
| self.assertEqual(os.lseek(f.fileno(), -10, 2), size+1-10) |
| self.assertEqual(os.lseek(f.fileno(), -size-1, 2), 0) |
| self.assertEqual(os.lseek(f.fileno(), size, 0), size) |
| # the 'a' that was written at the end of file above |
| self.assertEqual(f.read(1), 'a') |
| |
| def test_truncate(self): |
| if verbose: |
| print 'try truncate' |
| with open(TESTFN, 'r+b') as f: |
| # this is already decided before start running the test suite |
| # but we do it anyway for extra protection |
| if not hasattr(f, 'truncate'): |
| raise TestSkipped, "open().truncate() not available on this system" |
| f.seek(0, 2) |
| # else we've lost track of the true size |
| self.assertEqual(f.tell(), size+1) |
| # Cut it back via seek + truncate with no argument. |
| newsize = size - 10 |
| f.seek(newsize) |
| f.truncate() |
| self.assertEqual(f.tell(), newsize) # else pointer moved |
| f.seek(0, 2) |
| self.assertEqual(f.tell(), newsize) # else wasn't truncated |
| # Ensure that truncate(smaller than true size) shrinks |
| # the file. |
| newsize -= 1 |
| f.seek(42) |
| f.truncate(newsize) |
| self.assertEqual(f.tell(), 42) # else pointer moved |
| f.seek(0, 2) |
| self.assertEqual(f.tell(), newsize) # else wasn't truncated |
| |
| # XXX truncate(larger than true size) is ill-defined |
| # across platform; cut it waaaaay back |
| f.seek(0) |
| f.truncate(1) |
| self.assertEqual(f.tell(), 0) # else pointer moved |
| self.assertEqual(len(f.read()), 1) # else wasn't truncated |
| |
| |
| def test_main(): |
| # On Windows and Mac OSX this test comsumes large resources; It |
| # takes a long time to build the >2GB file and takes >2GB of disk |
| # space therefore the resource must be enabled to run this test. |
| # If not, nothing after this line stanza will be executed. |
| if sys.platform[:3] == 'win' or sys.platform == 'darwin': |
| requires('largefile', |
| 'test requires %s bytes and a long time to run' % str(size)) |
| else: |
| # Only run if the current filesystem supports large files. |
| # (Skip this test on Windows, since we now always support |
| # large files.) |
| f = open(TESTFN, 'wb') |
| try: |
| # 2**31 == 2147483648 |
| f.seek(2147483649L) |
| # Seeking is not enough of a test: you must write and |
| # flush, too! |
| f.write("x") |
| f.flush() |
| except (IOError, OverflowError): |
| f.close() |
| unlink(TESTFN) |
| raise TestSkipped, "filesystem does not have largefile support" |
| else: |
| f.close() |
| suite = unittest.TestSuite() |
| suite.addTest(TestCase('test_seek')) |
| suite.addTest(TestCase('test_osstat')) |
| suite.addTest(TestCase('test_seek_read')) |
| suite.addTest(TestCase('test_lseek')) |
| with open(TESTFN, 'w') as f: |
| if hasattr(f, 'truncate'): |
| suite.addTest(TestCase('test_truncate')) |
| unlink(TESTFN) |
| try: |
| run_unittest(suite) |
| finally: |
| unlink(TESTFN) |
| |
| |
| if __name__ == '__main__': |
| test_main() |
