diff --git a/src/tests/Makefile.am b/src/tests/Makefile.am
index 012ea4b..df126f0 100644
--- a/src/tests/Makefile.am
+++ b/src/tests/Makefile.am
@@ -10,6 +10,7 @@ displaytests = \
 	e2e-success.test \
 	e2e-failure.test \
 	emulation-back-tab.test \
+	unicode-combine-fallback-assert.test \
 	unicode-later-combining.test
 
 check_PROGRAMS = ocb-aes encrypt-decrypt
diff --git a/src/tests/unicode-combine-fallback-assert.test b/src/tests/unicode-combine-fallback-assert.test
new file mode 100755
index 0000000..5ed19c4
--- /dev/null
+++ b/src/tests/unicode-combine-fallback-assert.test
@@ -0,0 +1,41 @@
+#!/bin/sh
+
+#
+# This test is for Github issue 667
+# https://github.com/mobile-shell/mosh/issues/667
+# where mosh will assert when a combining character is printed on a
+# just-cleared cell.
+#
+# It just sends the offending output to mosh and expects it to not die.
+
+fail()
+{
+    printf "$@" 2>&1
+    exit 99
+}
+
+
+
+PATH=$PATH:.:$srcdir
+# Top-level wrapper.
+if [ $# -eq 0 ]; then
+    e2e-test $0 baseline
+    exit
+fi
+
+# OK, we have arguments, we're one of the test hooks.
+if [ $# -ne 1 ]; then
+    fail "bad arguments %s\n" "$@"
+fi
+
+baseline()
+{
+    printf '0\033[1J\xcc\xb4'
+}
+
+case $1 in
+    baseline)
+	baseline;;
+    *)
+	fail "unknown test argument %s\n" $1;;
+esac