mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-08-31 05:58:33 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 7

Issue 2986: Add autojunk paramater to SequenceMatcher to turn off heuristic. Patch by Terry Reedy, Eli Bendersky, and Simon Cross

Browse source
This commit is contained in:
Terry Reedy 2010-11-25 06:12:34 +00:00
parent bd86301070
commit 99f9637de8
4 changed files with 95 additions and 39 deletions
Download patch file Download diff file Expand all files Collapse all files

45
Lib/test/test_difflib.py
View file

@ -4,8 +4,47 @@ import unittest
import doctest
import sys
class TestSFbugs(unittest.TestCase):
class TestWithAscii(unittest.TestCase):
def test_one_insert(self):
sm = difflib.SequenceMatcher(None, 'b' * 100, 'a' + 'b' * 100)
self.assertAlmostEqual(sm.ratio(), 0.995, places=3)
self.assertEqual(list(sm.get_opcodes()),
[ ('insert', 0, 0, 0, 1),
('equal', 0, 100, 1, 101)])
sm = difflib.SequenceMatcher(None, 'b' * 100, 'b' * 50 + 'a' + 'b' * 50)
self.assertAlmostEqual(sm.ratio(), 0.995, places=3)
self.assertEqual(list(sm.get_opcodes()),
[ ('equal', 0, 50, 0, 50),
('insert', 50, 50, 50, 51),
('equal', 50, 100, 51, 101)])
def test_one_delete(self):
sm = difflib.SequenceMatcher(None, 'a' * 40 + 'c' + 'b' * 40, 'a' * 40 + 'b' * 40)
self.assertAlmostEqual(sm.ratio(), 0.994, places=3)
self.assertEqual(list(sm.get_opcodes()),
[ ('equal', 0, 40, 0, 40),
('delete', 40, 41, 40, 40),
('equal', 41, 81, 40, 80)])
class TestAutojunk(unittest.TestCase):
"""Tests for the autojunk parameter added in 2.7"""
def test_one_insert_homogenous_sequence(self):
# By default autojunk=True and the heuristic kicks in for a sequence
# of length 200+
seq1 = 'b' * 200
seq2 = 'a' + 'b' * 200
sm = difflib.SequenceMatcher(None, seq1, seq2)
self.assertAlmostEqual(sm.ratio(), 0, places=3)
# Now turn the heuristic off
sm = difflib.SequenceMatcher(None, seq1, seq2, autojunk=False)
self.assertAlmostEqual(sm.ratio(), 0.9975, places=3)
class TestSFbugs(unittest.TestCase):
def test_ratio_for_null_seqn(self):
# Check clearing of SF bug 763023
s = difflib.SequenceMatcher(None, [], [])
@ -184,7 +223,9 @@ class TestOutputFormat(unittest.TestCase):
def test_main():
difflib.HtmlDiff._default_prefix = 0
Doctests = doctest.DocTestSuite(difflib)
run_unittest(TestSFpatches, TestSFbugs, TestOutputFormat, Doctests)
run_unittest(
TestWithAscii, TestAutojunk, TestSFpatches, TestSFbugs,
TestOutputFormat, Doctests)
if __name__ == '__main__':
test_main()