--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-single-head-obsolescence-topic-B2.t	Thu Mar 12 02:08:39 2020 +0100
@@ -0,0 +1,115 @@
+
+=========================================
+Testing single head enforcement: Case A-2
+=========================================
+
+A repository is set to only accept a single head per name (typically named
+branch). However, obsolete changesets can make this enforcement more
+complicated, because they can be kept visible by other changeset on other
+branch.
+
+This case is part of a series of tests checking this behavior.
+
+Category B: Involving obsolescence with topic
+TestCase 2: A branch is split in two, effectively creating two heads
+
+.. old-state:
+..
+.. * 2 changeset changeset on topic X
+.. * 2 changeset changeset on topic Y on top of them.
+..
+.. new-state:
+..
+.. * 2 changeset changeset on topic Y at the same location
+.. * 1 changeset changeset on topic X unchanged
+.. * 1 changeset changeset on topic X superceeding the other ones
+..
+.. expected-result:
+..
+.. * two heads detected
+..
+.. graph-summary:
+..
+..   D ●      (topic-Y)
+..     |
+..   C ●      (topic-Y)
+..     |
+..   B ø⇠◔ B' (topic-X)
+..     | |
+..   A ● |    (topic-X)
+..     |/
+..     ●
+
+  $ . $TESTDIR/testlib/topic_setup.sh
+  $ . $TESTDIR/testlib/push-checkheads-util.sh
+
+Test setup
+----------
+
+  $ mkdir B2
+  $ cd B2
+  $ setuprepos single-head
+  creating basic server and client repo
+  updating to branch default
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ cd client
+  $ hg topic -r . topic-X
+  switching to topic topic-X
+  changed topic on 1 changesets to "topic-X"
+  $ hg strip --config extensions.strip= --hidden 'hidden()' --no-backup # clean old A0
+  $ mkcommit B0
+  $ hg branch Z
+  marked working directory as branch Z
+  $ hg topic topic-Y
+  $ mkcommit C0
+  active topic 'topic-Y' grew its first changeset
+  (see 'hg help topics' for more information)
+  $ mkcommit D0
+  $ hg push --new-branch
+  pushing to $TESTTMP/B2/server
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 4 changesets with 3 changes to 4 files (+1 heads)
+  1 new obsolescence markers
+  obsoleted 1 changesets
+  $ hg up 0
+  0 files updated, 0 files merged, 4 files removed, 0 files unresolved
+  $ hg topic topic-X
+  marked working directory as topic: topic-X
+  $ mkcommit B1
+  $ hg debugobsolete `getid "desc(B0)" ` `getid "desc(B1)"`
+  1 new obsolescence markers
+  obsoleted 1 changesets
+  2 new orphan changesets
+  $ hg log -G --hidden
+  @  5a4735b75167 [default:topic-X] (draft): B1
+  |
+  | *  02490b2dd1c5 [Z:topic-Y] (draft): D0
+  | |
+  | *  447ad8382abc [Z:topic-Y] (draft): C0
+  | |
+  | x  1c1f62b56685 [default:topic-X] (draft): B0
+  | |
+  | o  5a47a98cd8e5 [default:topic-X] (draft): A0
+  |/
+  o  1e4be0697311 [default] (public): root
+  
+
+Actual testing
+--------------
+
+(force push to make sure we get the changeset on the remote)
+
+  $ hg push -r 'desc("B1")' --force
+  pushing to $TESTTMP/B2/server
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  transaction abort!
+  rollback completed
+  abort: rejecting multiple heads on branch "default:topic-X"
+  (2 heads: 5a47a98cd8e5 5a4735b75167)
+  [255]