--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-diff-antipatience.t	Sat Mar 03 12:39:15 2018 -0800
@@ -0,0 +1,91 @@
+#testcases bdiff xdiff
+
+#if xdiff
+#require xdiff
+  $ cat >> $HGRCPATH <<EOF
+  > [experimental]
+  > xdiff = true
+  > EOF
+#endif
+
+Test case that makes use of the weakness of patience diff algorithm
+
+  $ hg init
+  >>> open('a', 'wb').write(b'\n'.join(list(b'a' + b'x' * 10 + b'u' + b'x' * 30 + b'a\n')))
+  $ hg commit -m 1 -A a
+  >>> open('a', 'wb').write(b'\n'.join(list(b'b' + b'x' * 30 + b'u' + b'x' * 10 + b'b\n')))
+#if xdiff
+  $ hg diff
+  diff -r f0aeecb49805 a
+  --- a/a	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/a	Thu Jan 01 00:00:00 1970 +0000
+  @@ -1,4 +1,4 @@
+  -a
+  +b
+   x
+   x
+   x
+  @@ -9,7 +9,6 @@
+   x
+   x
+   x
+  -u
+   x
+   x
+   x
+  @@ -30,6 +29,7 @@
+   x
+   x
+   x
+  +u
+   x
+   x
+   x
+  @@ -40,5 +40,5 @@
+   x
+   x
+   x
+  -a
+  +b
+   
+#else
+  $ hg diff
+  diff -r f0aeecb49805 a
+  --- a/a	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/a	Thu Jan 01 00:00:00 1970 +0000
+  @@ -1,15 +1,4 @@
+  -a
+  -x
+  -x
+  -x
+  -x
+  -x
+  -x
+  -x
+  -x
+  -x
+  -x
+  -u
+  +b
+   x
+   x
+   x
+  @@ -40,5 +29,16 @@
+   x
+   x
+   x
+  -a
+  +u
+  +x
+  +x
+  +x
+  +x
+  +x
+  +x
+  +x
+  +x
+  +x
+  +x
+  +b
+   
+#endif