diff --git a/tests/test-exchange-obsmarkers-case-A6.t b/tests/test-exchange-obsmarkers-case-A6.t
new file mode 100644
--- /dev/null
+++ b/tests/test-exchange-obsmarkers-case-A6.t
@@ -0,0 +1,150 @@
+============================================
+Testing obsolescence markers push: Cases A.6
+============================================
+
+Mercurial pushes obsolescences markers relevant to the "pushed-set", the set of
+all changesets that requested to be "in sync" after the push (even if they are
+already on both side).
+
+This test belongs to a series of tests checking such set is properly computed
+and applied. This does not tests "obsmarkers" discovery capabilities.
+
+Category A: simple cases
+TestCase 6: new markers between changesets already known on both side
+Variants:
+# a: explicit push
+# b: bare push
+
+A.6  new markers between changesets already known on both side
+==============================================================
+
+.. {{{
+..   A ◕⇠● B
+..     |/
+..     ● O
+.. }}}
+..
+.. Marker exist from:
+..
+..  * `A◕⇠● B`
+..
+.. Command runs:
+..
+..  * hg push -r B
+..  * hg push
+..
+.. Expected exchange:
+..
+..  * `A◕⇠● B`
+
+Setup
+-----
+
+  $ . $TESTDIR/testlib/exchange-obsmarker-util.sh
+
+initial
+
+  $ setuprepos A.6
+  creating test repo for test case A.6
+  - pulldest
+  - main
+  - pushdest
+  cd into `main` and proceed with env setup
+  $ cd main
+  $ mkcommit A0
+  $ hg update -q 0
+  $ mkcommit A1
+  created new head
+
+make both changeset known in remote
+
+  $ hg push -qf ../pushdest
+  $ hg push -qf ../pulldest
+
+create a marker after this
+
+  $ hg debugobsolete `getid 'desc(A0)'` `getid 'desc(A1)'`
+  $ hg log -G --hidden
+  @  e5ea8f9c7314 (draft): A1
+  |
+  | x  28b51eb45704 (draft): A0
+  |/
+  o  a9bdc8b26820 (public): O
+  
+  $ inspect_obsmarkers
+  obsstore content
+  ================
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  $ cd ..
+  $ cd ..
+
+  $ cp -R A.6 A.6.a
+  $ cp -R A.6 A.6.b
+
+Actual Test (explicit push version)
+-----------------------------------
+
+  $ dotest A.6.a A1
+  ## Running testcase A.6.a
+  # testing echange of "A1" (e5ea8f9c7314)
+  ## initial state
+  # obstore: main
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pushdest
+  # obstore: pulldest
+  ## pushing "A1" from main to pushdest
+  pushing to pushdest
+  searching for changes
+  no changes found
+  remote: 1 new obsolescence markers
+  ## post push state
+  # obstore: main
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pushdest
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pulldest
+  ## pulling "e5ea8f9c7314" from main into pulldest
+  pulling from main
+  no changes found
+  1 new obsolescence markers
+  ## post pull state
+  # obstore: main
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pushdest
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pulldest
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+
+Actual Test (bare push version)
+-------------------------------
+
+  $ dotest A.6.b
+  ## Running testcase A.6.b
+  ## initial state
+  # obstore: main
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pushdest
+  # obstore: pulldest
+  ## pushing from main to pushdest
+  pushing to pushdest
+  searching for changes
+  no changes found
+  remote: 1 new obsolescence markers
+  ## post push state
+  # obstore: main
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pushdest
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pulldest
+  ## pulling from main into pulldest
+  pulling from main
+  searching for changes
+  no changes found
+  1 new obsolescence markers
+  ## post pull state
+  # obstore: main
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pushdest
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pulldest
+  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}