1 import unittest 2 from test import test_support as support 3 4 import io # C implementation. 5 import _pyio as pyio # Python implementation. 6 7 # Simple test to ensure that optimizations in the IO library deliver the 8 # expected results. For best testing, run this under a debug-build Python too 9 # (to exercise asserts in the C code). 10 11 lengths = list(range(1, 257)) + [512, 1000, 1024, 2048, 4096, 8192, 10000, 12 16384, 32768, 65536, 1000000] 13 14 class BufferSizeTest(unittest.TestCase): 15 def try_one(self, s): 16 # Write s + "\n" + s to file, then open it and ensure that successive 17 # .readline()s deliver what we wrote. 18 19 # Ensure we can open TESTFN for writing. 20 support.unlink(support.TESTFN) 21 22 # Since C doesn't guarantee we can write/read arbitrary bytes in text 23 # files, use binary mode. 24 f = self.open(support.TESTFN, "wb") 25 try: 26 # write once with \n and once without 27 f.write(s) 28 f.write(b"\n") 29 f.write(s) 30 f.close() 31 f = open(support.TESTFN, "rb") 32 line = f.readline() 33 self.assertEqual(line, s + b"\n") 34 line = f.readline() 35 self.assertEqual(line, s) 36 line = f.readline() 37 self.assertTrue(not line) # Must be at EOF 38 f.close() 39 finally: 40 support.unlink(support.TESTFN) 41 42 def drive_one(self, pattern): 43 for length in lengths: 44 # Repeat string 'pattern' as often as needed to reach total length 45 # 'length'. Then call try_one with that string, a string one larger 46 # than that, and a string one smaller than that. Try this with all 47 # small sizes and various powers of 2, so we exercise all likely 48 # stdio buffer sizes, and "off by one" errors on both sides. 49 q, r = divmod(length, len(pattern)) 50 teststring = pattern * q + pattern[:r] 51 self.assertEqual(len(teststring), length) 52 self.try_one(teststring) 53 self.try_one(teststring + b"x") 54 self.try_one(teststring[:-1]) 55 56 def test_primepat(self): 57 # A pattern with prime length, to avoid simple relationships with 58 # stdio buffer sizes. 59 self.drive_one(b"1234567890\00\01\02\03\04\05\06") 60 61 def test_nullpat(self): 62 self.drive_one(bytes(1000)) 63 64 65 class CBufferSizeTest(BufferSizeTest): 66 open = io.open 67 68 class PyBufferSizeTest(BufferSizeTest): 69 open = staticmethod(pyio.open) 70 71 class BuiltinBufferSizeTest(BufferSizeTest): 72 open = open 73 74 75 def test_main(): 76 support.run_unittest(CBufferSizeTest, PyBufferSizeTest, BuiltinBufferSizeTest) 77 78 if __name__ == "__main__": 79 test_main() 80
