diff --git a/tests/test-exchange-obsmarkers-case-B6.t b/tests/test-exchange-obsmarkers-case-B6.t
new file mode 100644
--- /dev/null
+++ b/tests/test-exchange-obsmarkers-case-B6.t
@@ -0,0 +1,117 @@
+============================================
+Testing obsolescence markers push: Cases B.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 B: pruning case
+TestCase 6: Pruned changeset with precursors not in pushed set
+
+B.6 Pruned changeset with precursors not in pushed set
+======================================================
+
+.. {{{
+..   B ø⇠⊗ B'
+..     | |
+..   A ○ |
+..     |/
+..     ● O
+.. }}}
+..
+.. Marker exist from:
+..
+..  * `B ø⇠⊗ B'`
+..  * B' prune
+..
+.. Command run:
+..
+..  * hg push -r O
+..
+.. Expected exchange:
+..
+..  * `B ø⇠⊗ B'`
+..  * B' prune
+
+Setup
+-----
+
+  $ . $TESTDIR/testlib/exchange-obsmarker-util.sh
+
+Initial
+
+  $ setuprepos B.6
+  creating test repo for test case B.6
+  - pulldest
+  - main
+  - pushdest
+  cd into `main` and proceed with env setup
+  $ cd main
+  $ mkcommit A
+  $ mkcommit B0
+  $ hg up --quiet 0
+  $ mkcommit B1
+  created new head
+  $ hg debugobsolete `getid 'desc(B0)'` `getid 'desc(B1)'`
+  $ hg prune -qd '0 0' .
+  $ hg log -G --hidden
+  x  f6298a8ac3a4 (draft): B1
+  |
+  | x  962ecf6b1afc (draft): B0
+  | |
+  | o  f5bc6836db60 (draft): A
+  |/
+  @  a9bdc8b26820 (public): O
+  
+  $ inspect_obsmarkers
+  obsstore content
+  ================
+  962ecf6b1afc94e15c7e48fdfb76ef8abd11372b f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  $ cd ..
+  $ cd ..
+
+Actual Test
+-------------------------------------
+
+  $ dotest B.6 O
+  ## Running testcase B.6
+  # testing echange of "O" (a9bdc8b26820)
+  ## initial state
+  # obstore: main
+  962ecf6b1afc94e15c7e48fdfb76ef8abd11372b f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pushdest
+  # obstore: pulldest
+  ## pushing "O" from main to pushdest
+  pushing to pushdest
+  searching for changes
+  no changes found
+  remote: 2 new obsolescence markers
+  ## post push state
+  # obstore: main
+  962ecf6b1afc94e15c7e48fdfb76ef8abd11372b f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pushdest
+  962ecf6b1afc94e15c7e48fdfb76ef8abd11372b f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pulldest
+  ## pulling "a9bdc8b26820" from main into pulldest
+  pulling from main
+  no changes found
+  2 new obsolescence markers
+  ## post pull state
+  # obstore: main
+  962ecf6b1afc94e15c7e48fdfb76ef8abd11372b f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pushdest
+  962ecf6b1afc94e15c7e48fdfb76ef8abd11372b f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  # obstore: pulldest
+  962ecf6b1afc94e15c7e48fdfb76ef8abd11372b f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  f6298a8ac3a4b78bbeae5f1d3dc5bc3c3812f0f3 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+