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4d9d2563f5
Some applications (e.g. traditional Unix diff, version control
systems) neither know nor care about the encodings of the files they
are comparing. They are textual, but to the diff utility they are just
bytes. This worked fine under Python 2, because all of the hardcoded
strings in difflib.py are ASCII, so could safely be combined with
old-style u'' strings. But it stopped working in 3.x.
The solution is to use surrogate escapes for a lossless
bytes->str->bytes roundtrip. That means {unified,context}_diff() can
continue to just handle strings without worrying about bytes. Callers
who have to deal with bytes will need to change to using diff_bytes().
Use case: Mercurial's test runner uses difflib to compare current hg
output with known good output. But Mercurial's output is just bytes,
since it can contain:
* file contents (arbitrary unknown encoding)
* filenames (arbitrary unknown encoding)
* usernames and commit messages (usually UTF-8, but not guaranteed
because old versions of Mercurial did not enforce it)
* user messages (locale encoding)
Since the output of any given hg command can include text in multiple
encodings, it is hopeless to try to treat it as decodable Unicode
text. It's just bytes, all the way down.
This is an elaboration of a patch by Terry Reedy.
479 lines
18 KiB
Python
479 lines
18 KiB
Python
import difflib
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from test.support import run_unittest, findfile
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import unittest
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import doctest
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import sys
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class TestWithAscii(unittest.TestCase):
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def test_one_insert(self):
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sm = difflib.SequenceMatcher(None, 'b' * 100, 'a' + 'b' * 100)
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self.assertAlmostEqual(sm.ratio(), 0.995, places=3)
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self.assertEqual(list(sm.get_opcodes()),
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[ ('insert', 0, 0, 0, 1),
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('equal', 0, 100, 1, 101)])
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self.assertEqual(sm.bpopular, set())
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sm = difflib.SequenceMatcher(None, 'b' * 100, 'b' * 50 + 'a' + 'b' * 50)
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self.assertAlmostEqual(sm.ratio(), 0.995, places=3)
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self.assertEqual(list(sm.get_opcodes()),
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[ ('equal', 0, 50, 0, 50),
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('insert', 50, 50, 50, 51),
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('equal', 50, 100, 51, 101)])
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self.assertEqual(sm.bpopular, set())
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def test_one_delete(self):
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sm = difflib.SequenceMatcher(None, 'a' * 40 + 'c' + 'b' * 40, 'a' * 40 + 'b' * 40)
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self.assertAlmostEqual(sm.ratio(), 0.994, places=3)
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self.assertEqual(list(sm.get_opcodes()),
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[ ('equal', 0, 40, 0, 40),
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('delete', 40, 41, 40, 40),
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('equal', 41, 81, 40, 80)])
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def test_bjunk(self):
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sm = difflib.SequenceMatcher(isjunk=lambda x: x == ' ',
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a='a' * 40 + 'b' * 40, b='a' * 44 + 'b' * 40)
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self.assertEqual(sm.bjunk, set())
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sm = difflib.SequenceMatcher(isjunk=lambda x: x == ' ',
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a='a' * 40 + 'b' * 40, b='a' * 44 + 'b' * 40 + ' ' * 20)
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self.assertEqual(sm.bjunk, {' '})
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sm = difflib.SequenceMatcher(isjunk=lambda x: x in [' ', 'b'],
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a='a' * 40 + 'b' * 40, b='a' * 44 + 'b' * 40 + ' ' * 20)
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self.assertEqual(sm.bjunk, {' ', 'b'})
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class TestAutojunk(unittest.TestCase):
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"""Tests for the autojunk parameter added in 2.7"""
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def test_one_insert_homogenous_sequence(self):
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# By default autojunk=True and the heuristic kicks in for a sequence
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# of length 200+
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seq1 = 'b' * 200
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seq2 = 'a' + 'b' * 200
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sm = difflib.SequenceMatcher(None, seq1, seq2)
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self.assertAlmostEqual(sm.ratio(), 0, places=3)
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self.assertEqual(sm.bpopular, {'b'})
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# Now turn the heuristic off
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sm = difflib.SequenceMatcher(None, seq1, seq2, autojunk=False)
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self.assertAlmostEqual(sm.ratio(), 0.9975, places=3)
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self.assertEqual(sm.bpopular, set())
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class TestSFbugs(unittest.TestCase):
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def test_ratio_for_null_seqn(self):
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# Check clearing of SF bug 763023
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s = difflib.SequenceMatcher(None, [], [])
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self.assertEqual(s.ratio(), 1)
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self.assertEqual(s.quick_ratio(), 1)
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self.assertEqual(s.real_quick_ratio(), 1)
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def test_comparing_empty_lists(self):
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# Check fix for bug #979794
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group_gen = difflib.SequenceMatcher(None, [], []).get_grouped_opcodes()
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self.assertRaises(StopIteration, next, group_gen)
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diff_gen = difflib.unified_diff([], [])
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self.assertRaises(StopIteration, next, diff_gen)
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def test_matching_blocks_cache(self):
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# Issue #21635
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s = difflib.SequenceMatcher(None, "abxcd", "abcd")
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first = s.get_matching_blocks()
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second = s.get_matching_blocks()
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self.assertEqual(second[0].size, 2)
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self.assertEqual(second[1].size, 2)
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self.assertEqual(second[2].size, 0)
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def test_added_tab_hint(self):
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# Check fix for bug #1488943
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diff = list(difflib.Differ().compare(["\tI am a buggy"],["\t\tI am a bug"]))
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self.assertEqual("- \tI am a buggy", diff[0])
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self.assertEqual("? --\n", diff[1])
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self.assertEqual("+ \t\tI am a bug", diff[2])
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self.assertEqual("? +\n", diff[3])
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patch914575_from1 = """
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1. Beautiful is beTTer than ugly.
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2. Explicit is better than implicit.
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3. Simple is better than complex.
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4. Complex is better than complicated.
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"""
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patch914575_to1 = """
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1. Beautiful is better than ugly.
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3. Simple is better than complex.
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4. Complicated is better than complex.
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5. Flat is better than nested.
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"""
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patch914575_nonascii_from1 = """
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1. Beautiful is beTTer than ugly.
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2. Explicit is better than ımplıcıt.
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3. Simple is better than complex.
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4. Complex is better than complicated.
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"""
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patch914575_nonascii_to1 = """
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1. Beautiful is better than ügly.
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3. Sımple is better than complex.
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4. Complicated is better than cömplex.
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5. Flat is better than nested.
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"""
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patch914575_from2 = """
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\t\tLine 1: preceeded by from:[tt] to:[ssss]
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\t\tLine 2: preceeded by from:[sstt] to:[sssst]
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\t \tLine 3: preceeded by from:[sstst] to:[ssssss]
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Line 4: \thas from:[sst] to:[sss] after :
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Line 5: has from:[t] to:[ss] at end\t
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"""
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patch914575_to2 = """
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Line 1: preceeded by from:[tt] to:[ssss]
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\tLine 2: preceeded by from:[sstt] to:[sssst]
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Line 3: preceeded by from:[sstst] to:[ssssss]
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Line 4: has from:[sst] to:[sss] after :
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Line 5: has from:[t] to:[ss] at end
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"""
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patch914575_from3 = """line 0
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1234567890123456789012345689012345
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line 1
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line 2
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line 3
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line 4 changed
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line 5 changed
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line 6 changed
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line 7
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line 8 subtracted
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line 9
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1234567890123456789012345689012345
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short line
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just fits in!!
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just fits in two lines yup!!
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the end"""
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patch914575_to3 = """line 0
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1234567890123456789012345689012345
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line 1
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line 2 added
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line 3
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line 4 chanGEd
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line 5a chanGed
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line 6a changEd
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line 7
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line 8
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line 9
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1234567890
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another long line that needs to be wrapped
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just fitS in!!
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just fits in two lineS yup!!
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the end"""
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class TestSFpatches(unittest.TestCase):
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def test_html_diff(self):
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# Check SF patch 914575 for generating HTML differences
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f1a = ((patch914575_from1 + '123\n'*10)*3)
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t1a = (patch914575_to1 + '123\n'*10)*3
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f1b = '456\n'*10 + f1a
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t1b = '456\n'*10 + t1a
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f1a = f1a.splitlines()
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t1a = t1a.splitlines()
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f1b = f1b.splitlines()
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t1b = t1b.splitlines()
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f2 = patch914575_from2.splitlines()
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t2 = patch914575_to2.splitlines()
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f3 = patch914575_from3
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t3 = patch914575_to3
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i = difflib.HtmlDiff()
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j = difflib.HtmlDiff(tabsize=2)
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k = difflib.HtmlDiff(wrapcolumn=14)
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full = i.make_file(f1a,t1a,'from','to',context=False,numlines=5)
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tables = '\n'.join(
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[
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'<h2>Context (first diff within numlines=5(default))</h2>',
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i.make_table(f1a,t1a,'from','to',context=True),
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'<h2>Context (first diff after numlines=5(default))</h2>',
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i.make_table(f1b,t1b,'from','to',context=True),
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'<h2>Context (numlines=6)</h2>',
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i.make_table(f1a,t1a,'from','to',context=True,numlines=6),
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'<h2>Context (numlines=0)</h2>',
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i.make_table(f1a,t1a,'from','to',context=True,numlines=0),
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'<h2>Same Context</h2>',
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i.make_table(f1a,f1a,'from','to',context=True),
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'<h2>Same Full</h2>',
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i.make_table(f1a,f1a,'from','to',context=False),
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'<h2>Empty Context</h2>',
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i.make_table([],[],'from','to',context=True),
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'<h2>Empty Full</h2>',
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i.make_table([],[],'from','to',context=False),
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'<h2>tabsize=2</h2>',
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j.make_table(f2,t2),
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'<h2>tabsize=default</h2>',
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i.make_table(f2,t2),
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'<h2>Context (wrapcolumn=14,numlines=0)</h2>',
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k.make_table(f3.splitlines(),t3.splitlines(),context=True,numlines=0),
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'<h2>wrapcolumn=14,splitlines()</h2>',
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k.make_table(f3.splitlines(),t3.splitlines()),
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'<h2>wrapcolumn=14,splitlines(True)</h2>',
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k.make_table(f3.splitlines(True),t3.splitlines(True)),
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])
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actual = full.replace('</body>','\n%s\n</body>' % tables)
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# temporarily uncomment next two lines to baseline this test
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#with open('test_difflib_expect.html','w') as fp:
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# fp.write(actual)
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with open(findfile('test_difflib_expect.html')) as fp:
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self.assertEqual(actual, fp.read())
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def test_recursion_limit(self):
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# Check if the problem described in patch #1413711 exists.
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limit = sys.getrecursionlimit()
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old = [(i%2 and "K:%d" or "V:A:%d") % i for i in range(limit*2)]
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new = [(i%2 and "K:%d" or "V:B:%d") % i for i in range(limit*2)]
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difflib.SequenceMatcher(None, old, new).get_opcodes()
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def test_make_file_default_charset(self):
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html_diff = difflib.HtmlDiff()
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output = html_diff.make_file(patch914575_from1.splitlines(),
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patch914575_to1.splitlines())
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self.assertIn('content="text/html; charset=utf-8"', output)
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def test_make_file_iso88591_charset(self):
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html_diff = difflib.HtmlDiff()
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output = html_diff.make_file(patch914575_from1.splitlines(),
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patch914575_to1.splitlines(),
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charset='iso-8859-1')
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self.assertIn('content="text/html; charset=iso-8859-1"', output)
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def test_make_file_usascii_charset_with_nonascii_input(self):
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html_diff = difflib.HtmlDiff()
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output = html_diff.make_file(patch914575_nonascii_from1.splitlines(),
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patch914575_nonascii_to1.splitlines(),
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charset='us-ascii')
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self.assertIn('content="text/html; charset=us-ascii"', output)
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self.assertIn('ımplıcıt', output)
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class TestOutputFormat(unittest.TestCase):
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def test_tab_delimiter(self):
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args = ['one', 'two', 'Original', 'Current',
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'2005-01-26 23:30:50', '2010-04-02 10:20:52']
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ud = difflib.unified_diff(*args, lineterm='')
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self.assertEqual(list(ud)[0:2], [
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"--- Original\t2005-01-26 23:30:50",
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"+++ Current\t2010-04-02 10:20:52"])
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cd = difflib.context_diff(*args, lineterm='')
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self.assertEqual(list(cd)[0:2], [
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"*** Original\t2005-01-26 23:30:50",
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"--- Current\t2010-04-02 10:20:52"])
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def test_no_trailing_tab_on_empty_filedate(self):
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args = ['one', 'two', 'Original', 'Current']
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ud = difflib.unified_diff(*args, lineterm='')
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self.assertEqual(list(ud)[0:2], ["--- Original", "+++ Current"])
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cd = difflib.context_diff(*args, lineterm='')
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self.assertEqual(list(cd)[0:2], ["*** Original", "--- Current"])
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def test_range_format_unified(self):
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# Per the diff spec at http://www.unix.org/single_unix_specification/
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spec = '''\
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Each <range> field shall be of the form:
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%1d", <beginning line number> if the range contains exactly one line,
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and:
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"%1d,%1d", <beginning line number>, <number of lines> otherwise.
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If a range is empty, its beginning line number shall be the number of
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the line just before the range, or 0 if the empty range starts the file.
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'''
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fmt = difflib._format_range_unified
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self.assertEqual(fmt(3,3), '3,0')
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self.assertEqual(fmt(3,4), '4')
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self.assertEqual(fmt(3,5), '4,2')
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self.assertEqual(fmt(3,6), '4,3')
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self.assertEqual(fmt(0,0), '0,0')
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def test_range_format_context(self):
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# Per the diff spec at http://www.unix.org/single_unix_specification/
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spec = '''\
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The range of lines in file1 shall be written in the following format
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if the range contains two or more lines:
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"*** %d,%d ****\n", <beginning line number>, <ending line number>
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and the following format otherwise:
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"*** %d ****\n", <ending line number>
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The ending line number of an empty range shall be the number of the preceding line,
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or 0 if the range is at the start of the file.
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Next, the range of lines in file2 shall be written in the following format
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if the range contains two or more lines:
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"--- %d,%d ----\n", <beginning line number>, <ending line number>
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and the following format otherwise:
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"--- %d ----\n", <ending line number>
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'''
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fmt = difflib._format_range_context
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self.assertEqual(fmt(3,3), '3')
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self.assertEqual(fmt(3,4), '4')
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self.assertEqual(fmt(3,5), '4,5')
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self.assertEqual(fmt(3,6), '4,6')
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self.assertEqual(fmt(0,0), '0')
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class TestBytes(unittest.TestCase):
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# don't really care about the content of the output, just the fact
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# that it's bytes and we don't crash
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def check(self, diff):
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diff = list(diff) # trigger exceptions first
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for line in diff:
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self.assertIsInstance(
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line, bytes,
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"all lines of diff should be bytes, but got: %r" % line)
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def test_byte_content(self):
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# if we receive byte strings, we return byte strings
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a = [b'hello', b'andr\xe9'] # iso-8859-1 bytes
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b = [b'hello', b'andr\xc3\xa9'] # utf-8 bytes
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unified = difflib.unified_diff
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context = difflib.context_diff
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check = self.check
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check(difflib.diff_bytes(unified, a, a))
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check(difflib.diff_bytes(unified, a, b))
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# now with filenames (content and filenames are all bytes!)
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check(difflib.diff_bytes(unified, a, a, b'a', b'a'))
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check(difflib.diff_bytes(unified, a, b, b'a', b'b'))
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# and with filenames and dates
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check(difflib.diff_bytes(unified, a, a, b'a', b'a', b'2005', b'2013'))
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check(difflib.diff_bytes(unified, a, b, b'a', b'b', b'2005', b'2013'))
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# same all over again, with context diff
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check(difflib.diff_bytes(context, a, a))
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check(difflib.diff_bytes(context, a, b))
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check(difflib.diff_bytes(context, a, a, b'a', b'a'))
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check(difflib.diff_bytes(context, a, b, b'a', b'b'))
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check(difflib.diff_bytes(context, a, a, b'a', b'a', b'2005', b'2013'))
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check(difflib.diff_bytes(context, a, b, b'a', b'b', b'2005', b'2013'))
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def test_byte_filenames(self):
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# somebody renamed a file from ISO-8859-2 to UTF-8
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fna = b'\xb3odz.txt' # "łodz.txt"
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fnb = b'\xc5\x82odz.txt'
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# they transcoded the content at the same time
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a = [b'\xa3odz is a city in Poland.']
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b = [b'\xc5\x81odz is a city in Poland.']
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check = self.check
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unified = difflib.unified_diff
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context = difflib.context_diff
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check(difflib.diff_bytes(unified, a, b, fna, fnb))
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check(difflib.diff_bytes(context, a, b, fna, fnb))
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def assertDiff(expect, actual):
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# do not compare expect and equal as lists, because unittest
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# uses difflib to report difference between lists
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actual = list(actual)
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self.assertEqual(len(expect), len(actual))
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for e, a in zip(expect, actual):
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self.assertEqual(e, a)
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expect = [
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b'--- \xb3odz.txt',
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b'+++ \xc5\x82odz.txt',
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b'@@ -1 +1 @@',
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b'-\xa3odz is a city in Poland.',
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b'+\xc5\x81odz is a city in Poland.',
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]
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actual = difflib.diff_bytes(unified, a, b, fna, fnb, lineterm=b'')
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assertDiff(expect, actual)
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# with dates (plain ASCII)
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datea = b'2005-03-18'
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dateb = b'2005-03-19'
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check(difflib.diff_bytes(unified, a, b, fna, fnb, datea, dateb))
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check(difflib.diff_bytes(context, a, b, fna, fnb, datea, dateb))
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expect = [
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# note the mixed encodings here: this is deeply wrong by every
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# tenet of Unicode, but it doesn't crash, it's parseable by
|
||
# patch, and it's how UNIX(tm) diff behaves
|
||
b'--- \xb3odz.txt\t2005-03-18',
|
||
b'+++ \xc5\x82odz.txt\t2005-03-19',
|
||
b'@@ -1 +1 @@',
|
||
b'-\xa3odz is a city in Poland.',
|
||
b'+\xc5\x81odz is a city in Poland.',
|
||
]
|
||
actual = difflib.diff_bytes(unified, a, b, fna, fnb, datea, dateb,
|
||
lineterm=b'')
|
||
assertDiff(expect, actual)
|
||
|
||
def test_mixed_types_content(self):
|
||
# type of input content must be consistent: all str or all bytes
|
||
a = [b'hello']
|
||
b = ['hello']
|
||
|
||
unified = difflib.unified_diff
|
||
context = difflib.context_diff
|
||
|
||
expect = "lines to compare must be str, not bytes (b'hello')"
|
||
self._assert_type_error(expect, unified, a, b)
|
||
self._assert_type_error(expect, unified, b, a)
|
||
self._assert_type_error(expect, context, a, b)
|
||
self._assert_type_error(expect, context, b, a)
|
||
|
||
expect = "all arguments must be bytes, not str ('hello')"
|
||
self._assert_type_error(expect, difflib.diff_bytes, unified, a, b)
|
||
self._assert_type_error(expect, difflib.diff_bytes, unified, b, a)
|
||
self._assert_type_error(expect, difflib.diff_bytes, context, a, b)
|
||
self._assert_type_error(expect, difflib.diff_bytes, context, b, a)
|
||
|
||
def test_mixed_types_filenames(self):
|
||
# cannot pass filenames as bytes if content is str (this may not be
|
||
# the right behaviour, but at least the test demonstrates how
|
||
# things work)
|
||
a = ['hello\n']
|
||
b = ['ohell\n']
|
||
fna = b'ol\xe9.txt' # filename transcoded from ISO-8859-1
|
||
fnb = b'ol\xc3a9.txt' # to UTF-8
|
||
self._assert_type_error(
|
||
"all arguments must be str, not: b'ol\\xe9.txt'",
|
||
difflib.unified_diff, a, b, fna, fnb)
|
||
|
||
def test_mixed_types_dates(self):
|
||
# type of dates must be consistent with type of contents
|
||
a = [b'foo\n']
|
||
b = [b'bar\n']
|
||
datea = '1 fév'
|
||
dateb = '3 fév'
|
||
self._assert_type_error(
|
||
"all arguments must be bytes, not str ('1 fév')",
|
||
difflib.diff_bytes, difflib.unified_diff,
|
||
a, b, b'a', b'b', datea, dateb)
|
||
|
||
# if input is str, non-ASCII dates are fine
|
||
a = ['foo\n']
|
||
b = ['bar\n']
|
||
list(difflib.unified_diff(a, b, 'a', 'b', datea, dateb))
|
||
|
||
def _assert_type_error(self, msg, generator, *args):
|
||
with self.assertRaises(TypeError) as ctx:
|
||
list(generator(*args))
|
||
self.assertEqual(msg, str(ctx.exception))
|
||
|
||
|
||
def test_main():
|
||
difflib.HtmlDiff._default_prefix = 0
|
||
Doctests = doctest.DocTestSuite(difflib)
|
||
run_unittest(
|
||
TestWithAscii, TestAutojunk, TestSFpatches, TestSFbugs,
|
||
TestOutputFormat, TestBytes, Doctests)
|
||
|
||
if __name__ == '__main__':
|
||
test_main()
|