new file mode 100644
--- /dev/null
+++ b/tests/test-merge-subrepos.t
@@ -0,0 +1,25 @@
+  $ hg init
+
+  $ echo a > a
+  $ hg ci -qAm 'add a'
+
+  $ hg init subrepo
+  $ echo 'subrepo = http://example.net/libfoo' > .hgsub
+  $ hg ci -qAm 'added subrepo'
+
+  $ hg up -qC 0
+  $ echo ax > a
+  $ hg ci -m 'changed a'
+  created new head
+
+  $ hg up -qC 1
+  $ cd subrepo
+  $ echo b > b
+  $ hg add b
+  $ cd ..
+
+Should fail, since there are added files to subrepo:
+
+  $ hg merge
+  abort: outstanding uncommitted changes in subrepository 'subrepo'
+  [255]