import unittest from test.support import os_helper import io # C implementation. import _pyio as pyio # Python implementation. # Simple test to ensure that optimizations in the IO library deliver the # expected results. For best testing, run this under a debug-build Python too # (to exercise asserts in the C code). lengths = list(range(1, 257)) + [512, 1000, 1024, 2048, 4096, 8192, 10000, 16384, 32768, 65536, 1000000] class BufferSizeTest: def try_one(self, s): # Write s + "\n" + s to file, then open it and ensure that successive # .readline()s deliver what we wrote. # Ensure we can open TESTFN for writing. os_helper.unlink(os_helper.TESTFN) # Since C doesn't guarantee we can write/read arbitrary bytes in text # files, use binary mode. f = self.open(os_helper.TESTFN, "wb") try: # write once with \n and once without f.write(s) f.write(b"\n") f.write(s) f.close() f = open(os_helper.TESTFN, "rb") line = f.readline() self.assertEqual(line, s + b"\n") line = f.readline() self.assertEqual(line, s) line = f.readline() self.assertFalse(line) # Must be at EOF f.close() finally: os_helper.unlink(os_helper.TESTFN) def drive_one(self, pattern): for length in lengths: # 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. Try this with all # small sizes and various powers of 2, so we exercise all likely # stdio buffer sizes, and "off by one" errors on both sides. q, r = divmod(length, len(pattern)) teststring = pattern * q + pattern[:r] self.assertEqual(len(teststring), length) self.try_one(teststring) self.try_one(teststring + b"x") self.try_one(teststring[:-1]) def test_primepat(self): # A pattern with prime length, to avoid simple relationships with # stdio buffer sizes. self.drive_one(b"1234567890\00\01\02\03\04\05\06") def test_nullpat(self): self.drive_one(b'\0' * 1000) class CBufferSizeTest(BufferSizeTest, unittest.TestCase): open = io.open class PyBufferSizeTest(BufferSizeTest, unittest.TestCase): open = staticmethod(pyio.open) if __name__ == "__main__": unittest.main()