--- a/tests/test-update-branches.t	Tue Apr 16 15:16:33 2013 +0200
+++ b/tests/test-update-branches.t	Tue Apr 16 15:33:18 2013 +0200
@@ -164,3 +164,63 @@
   parent=1
   M foo
 
+Test obsolescence behavior
+---------------------------------------------------------------------
+
+successors should be taken in account when checking head destination
+
+  $ cat << EOF >> $HGRCPATH
+  > [extensions]
+  > obs=$TESTTMP/obs.py
+  > [ui]
+  > logtemplate={rev}:{node|short} {desc|firstline}
+  > EOF
+  $ cat > $TESTTMP/obs.py << EOF
+  > import mercurial.obsolete
+  > mercurial.obsolete._enabled = True
+  > EOF
+
+Test no-argument update to a successor of an obsoleted changeset
+
+  $ hg log -G
+  o  5:ff252e8273df 5
+  |
+  o  4:d047485b3896 4
+  |
+  | o  3:6efa171f091b 3
+  | |
+  | | o  2:bd10386d478c 2
+  | |/
+  | @  1:0786582aa4b1 1
+  |/
+  o  0:60829823a42a 0
+  
+  $ hg status
+  M foo
+
+We add simple obsolescence marker between 3 and 4 (indirect successors)
+
+  $ hg id --debug -i -r 3
+  6efa171f091b00a3c35edc15d48c52a498929953
+  $ hg id --debug -i -r 4
+  d047485b3896813b2a624e86201983520f003206
+  $ hg debugobsolete 6efa171f091b00a3c35edc15d48c52a498929953 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+  $ hg debugobsolete aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa d047485b3896813b2a624e86201983520f003206
+
+Test that 5 is detected as a valid destination from 3
+  $ hg up --quiet --hidden 3
+  $ hg up 5
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+
+Test that 5 is detected as a valid destination from 1
+  $ hg up --quiet 0          # we should be able to update to 3 directly
+  $ hg up --quiet --hidden 3 # but not implemented yet.
+  $ hg up 5
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+
+Test that 5 is not detected as a valid destination from 2
+  $ hg up --quiet 0
+  $ hg up --quiet 2
+  $ hg up 5
+  abort: crosses branches (merge branches or use --clean to discard changes)
+  [255]