diff --git a/authfs/tools/test.sh b/authfs/tools/test.sh
new file mode 100755
index 0000000..9ed3a99
--- /dev/null
+++ b/authfs/tools/test.sh
@@ -0,0 +1,42 @@
+#!/bin/bash
+
+# Run with -u to enter new namespace.
+if [[ $1 == "-u" ]]; then
+  exec unshare -m -U -r $0
+fi
+
+trap "umount /tmp/mnt" EXIT;
+mkdir -p /tmp/mnt
+
+echo "Mounting authfs in background ..."
+strace -o authfs.strace target/debug/authfs \
+  /tmp/mnt \
+  --local-verified-file 2:testdata/input.4m:testdata/input.4m.merkle_dump:testdata/input.4m.fsv_sig \
+  --local-verified-file 3:testdata/input.4k1:testdata/input.4k1.merkle_dump:testdata/input.4k1.fsv_sig \
+  --local-verified-file 4:testdata/input.4k:testdata/input.4k.merkle_dump:testdata/input.4k.fsv_sig \
+  --local-unverified-file 5:testdata/input.4k \
+  &
+sleep 0.1
+
+echo "Accessing files in authfs ..."
+echo
+md5sum /tmp/mnt/2 testdata/input.4m
+echo
+md5sum /tmp/mnt/3 testdata/input.4k1
+echo
+md5sum /tmp/mnt/4 /tmp/mnt/5 testdata/input.4k
+echo
+dd if=/tmp/mnt/2 bs=1000 skip=100 count=50 status=none |md5sum
+dd if=testdata/input.4m bs=1000 skip=100 count=50 status=none |md5sum
+echo
+tac /tmp/mnt/4 |md5sum
+tac /tmp/mnt/5 |md5sum
+tac testdata/input.4k |md5sum
+echo
+test -f /tmp/mnt/2 || echo 'FAIL: an expected file is missing'
+test -f /tmp/mnt/0 && echo 'FAIL: unexpected file presents'
+test -f /tmp/mnt/1 && echo 'FAIL: unexpected file presents, 1 is root dir'
+test -f /tmp/mnt/100 && echo 'FAIL: unexpected file presents'
+test -f /tmp/mnt/foo && echo 'FAIL: unexpected file presents'
+test -f /tmp/mnt/dir/3 && echo 'FAIL: unexpected file presents'
+echo "Done!"