[extensions-web] diffutils: Fix some more, add test cases

[Jasper St. Pierre <jstpierre src gnome org>]

commit cc7630d7cc654d0e009426fbc0aa6157eec4f636
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Sun Aug 19 17:02:30 2012 -0400

    diffutils: Fix some more, add test cases
    
    We can't blindly be making changes like this unless we're sure we're
    improving and not regressing. Add test cases, to be expanded later.

 sweettooth/review/difftests.py |   50 ++++++++++++++++++++++++++++++++++++++++
 sweettooth/review/diffutils.py |   25 ++++++++-----------
 sweettooth/review/tests.py     |    2 +
 3 files changed, 63 insertions(+), 14 deletions(-)
---
diff --git a/sweettooth/review/difftests.py b/sweettooth/review/difftests.py
new file mode 100644
index 0000000..da8fac1
--- /dev/null
+++ b/sweettooth/review/difftests.py
@@ -0,0 +1,50 @@
+
+from unittest import TestCase
+from diffutils import get_chunks, new_chunk, new_line
+
+def strip_regions(chunks):
+    for chunk in chunks:
+        for L in chunk['lines']:
+            L['oldregion'] = None
+            L['newregion'] = None
+
+class DiffTest(TestCase):
+    def assertDiff(self, a, b, expected, test_regions=False):
+        resulted = list(get_chunks(a, b))
+        if not test_regions:
+            strip_regions(resulted)
+
+        self.assertEqual(resulted, expected)
+
+    def testFakeUnchanged(self):
+        a = ["a"]
+        b = ["a"]
+        self.assertDiff(a, b, [])
+
+    def testFakeDeleted(self):
+        a = ["a"]
+        b = None
+        self.assertDiff(a, b, [new_chunk(tag='delete', lines=[new_line(0, 0)])])
+
+    def testFakeInserted(self):
+        a = None
+        b = ["a"]
+        self.assertDiff(a, b, [new_chunk(tag='insert', lines=[new_line(0, 0)])])
+
+    def testBasicInsert(self):
+        a = ["a"]
+        b = ["a", "b"]
+        self.assertDiff(a, b, [new_chunk(tag='equal', lines=[new_line(0, 0)]),
+                               new_chunk(tag='insert', lines=[new_line(None, 1)])])
+
+    def testBasicDelete(self):
+        a = ["a", "b"]
+        b = ["a"]
+        self.assertDiff(a, b, [new_chunk(tag='equal', lines=[new_line(0, 0)]),
+                               new_chunk(tag='delete', lines=[new_line(1, None)])])
+
+    def testBasicReplace(self):
+        a = ["a", "b"]
+        b = ["a", "c"]
+        self.assertDiff(a, b, [new_chunk(tag='equal', lines=[new_line(0, 0)]),
+                               new_chunk(tag='replace', lines=[new_line(1, 1)])])
diff --git a/sweettooth/review/diffutils.py b/sweettooth/review/diffutils.py
index 08635b5..a56a4b1 100644
--- a/sweettooth/review/diffutils.py
+++ b/sweettooth/review/diffutils.py
@@ -708,10 +708,7 @@ def new_chunk(lines, collapsable=False, tag='equal'):
     }
 
 def get_fake_chunk(numlines, tag):
-    linenums = xrange(numlines)
-    lines = [dict(oldlinenum=n+1, newlinenum=n+1,
-                  oldindex=n, newindex=n,
-                  oldregion=[], newregion=[]) for n in linenums]
+    lines = [new_line(oldindex=n, newindex=n) for n in xrange(numlines)]
     return new_chunk(lines, tag=tag)
 
 def get_linenum(idx):
@@ -720,18 +717,18 @@ def get_linenum(idx):
     else:
         return None
 
+def new_line(oldindex, newindex, oldregion=None, newregion=None):
+    oldlinenum, newlinenum = get_linenum(oldindex), get_linenum(newindex)
+    return dict(oldlinenum=oldlinenum, newlinenum=newlinenum,
+                oldindex=oldindex, newindex=newindex,
+                oldregion=oldregion, newregion=newregion)
+
 def diff_line(old, new):
     oldindex, oldline = old
     newindex, newline = new
 
     oldregion, newregion = get_line_changed_regions(oldline, newline)
-    oldlinenum, newlinenum = get_linenum(oldindex), get_linenum(newindex)
-
-    result = dict(oldlinenum=oldlinenum, newlinenum=newlinenum,
-                  oldindex=oldindex, newindex=newindex,
-                  oldregion=oldregion, newregion=newregion)
-
-    return result
+    return new_line(oldindex, newindex, oldregion, newregion)
 
 def get_chunks(a, b):
     if a == b:
@@ -760,10 +757,10 @@ def get_chunks(a, b):
     for tag, i1, i2, j1, j2 in differ.get_opcodes():
         numlines = max(i2-i1, j2-j1)
 
-        oldlines = izip_longest(xrange(i1, i2), a[i1:j2])
-        newlines = izip_longest(xrange(j1, j2), b[j1:j2])
+        oldlines = zip(xrange(i1, i2), a[i1:i2])
+        newlines = zip(xrange(j1, j2), b[j1:j2])
 
-        lines = [diff_line(old, new) for old, new in zip(oldlines, newlines)]
+        lines = [diff_line(old, new) for old, new in izip_longest(oldlines, newlines, fillvalue=(None, None))]
 
         if tag == 'equal' and numlines > collapse_threshold:
             last_range_start = numlines - context_num_lines
diff --git a/sweettooth/review/tests.py b/sweettooth/review/tests.py
index ef25a89..01f2cb5 100644
--- a/sweettooth/review/tests.py
+++ b/sweettooth/review/tests.py
@@ -7,6 +7,8 @@ from review.views import get_old_version, should_auto_approve
 
 from testutils import BasicUserTestCase
 
+from difftests import DiffTests
+
 class DiffViewTest(BasicUserTestCase, TestCase):
     def test_get_zipfiles(self):
         metadata = {"uuid": "test-metadata mecheye net",