new file mode 100755
--- /dev/null
+++ b/tests/test-empty-group
@@ -0,0 +1,49 @@
+#!/bin/sh
+#
+# A B
+#
+# 3 4 3
+# |\/| |\
+# |/\| | \
+# 1 2 1 2
+# \ / \ /
+# 0 0
+#
+# if the result of the merge of 1 and 2
+# is the same in 3 and 4, no new manifest
+# will be created and the manifest group
+# will be empty during the pull
+#
+# (plus we test a failure where outgoing
+# wrongly reported the number of csets)
+#
+
+hg init a
+cd a
+touch init
+hg ci -A -m 0 -d "1000000 0"
+touch x y
+hg ci -A -m 1 -d "1000000 0"
+hg update 0
+touch x y
+hg ci -A -m 2 -d "1000000 0"
+hg merge 1
+hg ci -A -m m1 -d "1000000 0"
+#hg log
+#hg debugindex .hg/00manifest.i
+hg update -C 1
+hg merge 2
+hg ci -A -m m2 -d "1000000 0"
+#hg log
+#hg debugindex .hg/00manifest.i
+
+cd ..
+hg clone -r 3 a b
+hg clone -r 4 a c
+hg -R a outgoing b
+hg -R a outgoing c
+hg -R b outgoing c
+hg -R c outgoing b
+
+hg -R b pull a
+hg -R c pull a