tests: finish updating test-bdiff to unittest (part 4 of 4)

tests/test-bdiff.py

@@ -1,140 +1,141 b''
 from __future__ import absolute_import, print_function
 import collections
 import struct
 import unittest
 
 import silenttestrunner
 
 from mercurial import (
     bdiff,
     mpatch,
 )
 
 class diffreplace(
     collections.namedtuple('diffreplace', 'start end from_ to')):
     def __repr__(self):
         return 'diffreplace(%r, %r, %r, %r)' % self
 
 class BdiffTests(unittest.TestCase):
 
     def assert_bdiff_applies(self, a, b):
         d = bdiff.bdiff(a, b)
         c = a
         if d:
             c = mpatch.patches(a, [d])
         self.assertEqual(
             c, b, ("bad diff+patch result from\n  %r to\n  "
                    "%r: \nbdiff: %r\npatched: %r" % (a, b, d, c[:200])))
 
     def assert_bdiff(self, a, b):
         self.assert_bdiff_applies(a, b)
         self.assert_bdiff_applies(b, a)
 
     def test_bdiff_basic(self):
         cases = [
             ("a\nc\n\n\n\n", "a\nb\n\n\n"),
             ("a\nb\nc\n", "a\nc\n"),
             ("", ""),
             ("a\nb\nc", "a\nb\nc"),
             ("a\nb\nc\nd\n", "a\nd\n"),
             ("a\nb\nc\nd\n", "a\nc\ne\n"),
             ("a\nb\nc\n", "a\nc\n"),
             ("a\n", "c\na\nb\n"),
             ("a\n", ""),
             ("a\n", "b\nc\n"),
             ("a\n", "c\na\n"),
             ("", "adjfkjdjksdhfksj"),
             ("", "ab"),
             ("", "abc"),
             ("a", "a"),
             ("ab", "ab"),
             ("abc", "abc"),
             ("a\n", "a\n"),
             ("a\nb", "a\nb"),
         ]
         for a, b in cases:
             self.assert_bdiff(a, b)
 
     def showdiff(self, a, b):
         bin = bdiff.bdiff(a, b)
         pos = 0
         q = 0
         actions = []
         while pos < len(bin):
             p1, p2, l = struct.unpack(">lll", bin[pos:pos + 12])
             pos += 12
             if p1:
                 actions.append(a[q:p1])
             actions.append(diffreplace(p1, p2, a[p1:p2], bin[pos:pos + l]))
             pos += l
             q = p2
         if q < len(a):
             actions.append(a[q:])
         return actions
 
     def test_issue1295(self):
         cases = [
             ("x\n\nx\n\nx\n\nx\n\nz\n", "x\n\nx\n\ny\n\nx\n\nx\n\nz\n",
              ['x\n\nx\n\n', diffreplace(6, 6, '', 'y\n\n'), 'x\n\nx\n\nz\n']),
             ("x\n\nx\n\nx\n\nx\n\nz\n", "x\n\nx\n\ny\n\nx\n\ny\n\nx\n\nz\n",
              ['x\n\nx\n\n',
               diffreplace(6, 6, '', 'y\n\n'),
               'x\n\n',
               diffreplace(9, 9, '', 'y\n\n'),
               'x\n\nz\n']),
             # we should pick up abbbc. rather than bc.de as the longest match
             ("a\nb\nb\nb\nc\n.\nd\ne\n.\nf\n",
              "a\nb\nb\na\nb\nb\nb\nc\n.\nb\nc\n.\nd\ne\nf\n",
              ['a\nb\nb\n',
               diffreplace(6, 6, '', 'a\nb\nb\nb\nc\n.\n'),
               'b\nc\n.\nd\ne\n',
               diffreplace(16, 18, '.\n', ''),
               'f\n']),
         ]
         for old, new, want in cases:
             self.assertEqual(self.showdiff(old, new), want)
 
     def test_fixws(self):
         cases = [
             (" \ta\r b\t\n", "ab\n", 1),
             (" \ta\r b\t\n", " a b\n", 0),
             ("", "", 1),
             ("", "", 0),
         ]
         for a, b, allws in cases:
             c = bdiff.fixws(a, allws)
             self.assertEqual(
                 c, b, 'fixws(%r) want %r got %r (allws=%r)' % (a, b, c, allws))
 
-def showdiff(a, b):
-    print('showdiff(\n  %r,\n  %r):' % (a, b))
-    bin = bdiff.bdiff(a, b)
-    pos = 0
-    q = 0
-    while pos < len(bin):
-        p1, p2, l = struct.unpack(">lll", bin[pos:pos + 12])
-        pos += 12
-        if p1:
-            print('', repr(a[q:p1]))
-        print('', p1, p2, repr(a[p1:p2]), '->', repr(bin[pos:pos + l]))
-        pos += l
-        q = p2
-    if q < len(a):
-        print('', repr(a[q:]))
+    def test_nice_diff_for_trivial_change(self):
+        self.assertEqual(self.showdiff(
+            ''.join('<%s\n-\n' % i for i in range(5)),
+            ''.join('>%s\n-\n' % i for i in range(5))),
+                         [diffreplace(0, 3, '<0\n', '>0\n'),
+                          '-\n',
+                          diffreplace(5, 8, '<1\n', '>1\n'),
+                          '-\n',
+                          diffreplace(10, 13, '<2\n', '>2\n'),
+                          '-\n',
+                          diffreplace(15, 18, '<3\n', '>3\n'),
+                          '-\n',
+                          diffreplace(20, 23, '<4\n', '>4\n'),
+                          '-\n'])
 
-print("Nice diff for a trivial change:")
-showdiff(
-    ''.join('<%s\n-\n' % i for i in range(5)),
-    ''.join('>%s\n-\n' % i for i in range(5)))
+    def test_prefer_appending(self):
+        # 1 line to 3 lines
+        self.assertEqual(self.showdiff('a\n', 'a\n' * 3),
+                         ['a\n', diffreplace(2, 2, '', 'a\na\n')])
+        # 1 line to 5 lines
+        self.assertEqual(self.showdiff('a\n', 'a\n' * 5),
+                         ['a\n', diffreplace(2, 2, '', 'a\na\na\na\n')])
 
-print("Diff 1 to 3 lines - preference for appending:")
-showdiff('a\n', 'a\n' * 3)
-print("Diff 1 to 5 lines - preference for appending:")
-showdiff('a\n', 'a\n' * 5)
-print("Diff 3 to 1 lines - preference for removing trailing lines:")
-showdiff('a\n' * 3, 'a\n')
-print("Diff 5 to 1 lines - preference for removing trailing lines:")
-showdiff('a\n' * 5, 'a\n')
+    def test_prefer_removing_trailing(self):
+        # 3 lines to 1 line
+        self.assertEqual(self.showdiff('a\n' * 3, 'a\n'),
+                         ['a\n', diffreplace(2, 6, 'a\na\n', '')])
+        # 5 lines to 1 line
+        self.assertEqual(self.showdiff('a\n' * 5, 'a\n'),
+                         ['a\n', diffreplace(2, 10, 'a\na\na\na\n', '')])
 
 if __name__ == '__main__':
     silenttestrunner.main(__name__)