Speed up next() by disabling snapshot updating then.
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index 5542a5b..7a2bdb2 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -1,6 +1,7 @@
"""Unit tests for io.py."""
import sys
+import time
import unittest
from itertools import chain
from test import test_support
@@ -549,6 +550,63 @@
rlines.append((pos, line))
self.assertEquals(rlines, wlines)
+ def testTelling(self):
+ f = io.open(test_support.TESTFN, "w+", encoding="utf8")
+ p0 = f.tell()
+ f.write(u"\xff\n")
+ p1 = f.tell()
+ f.write(u"\xff\n")
+ p2 = f.tell()
+ f.seek(0)
+ self.assertEquals(f.tell(), p0)
+ self.assertEquals(f.readline(), u"\xff\n")
+ self.assertEquals(f.tell(), p1)
+ self.assertEquals(f.readline(), u"\xff\n")
+ self.assertEquals(f.tell(), p2)
+ f.seek(0)
+ for line in f:
+ self.assertEquals(line, u"\xff\n")
+ self.assertRaises(IOError, f.tell)
+ self.assertEquals(f.tell(), p2)
+ f.close()
+
+ def timingTest(self):
+ timer = time.time
+ enc = "utf8"
+ line = u"\0\x0f\xff\u0fff\uffff\U000fffff\U0010ffff"*3 + "\n"
+ nlines = 10000
+ nchars = len(line)
+ nbytes = len(line.encode(enc))
+ for chunk_size in (32, 64, 128, 256):
+ f = io.open(test_support.TESTFN, "w+", encoding=enc)
+ f._CHUNK_SIZE = chunk_size
+ t0 = timer()
+ for i in range(nlines):
+ f.write(line)
+ f.flush()
+ t1 = timer()
+ f.seek(0)
+ for line in f:
+ pass
+ t2 = timer()
+ f.seek(0)
+ while f.readline():
+ pass
+ t3 = timer()
+ f.seek(0)
+ while f.readline():
+ f.tell()
+ t4 = timer()
+ f.close()
+ if test_support.verbose:
+ print("\nTiming test: %d lines of %d characters (%d bytes)" %
+ (nlines, nchars, nbytes))
+ print("File chunk size: %6s" % f._CHUNK_SIZE)
+ print("Writing: %6.3f seconds" % (t1-t0))
+ print("Reading using iteration: %6.3f seconds" % (t2-t1))
+ print("Reading using readline(): %6.3f seconds" % (t3-t2))
+ print("Using readline()+tell(): %6.3f seconds" % (t4-t3))
+
# XXX Tests for open()