diff --git a/selftest/lock_test/lock_test.sh b/selftest/lock_test/lock_test.sh
new file mode 100755
index 0000000..9e4f44a
--- /dev/null
+++ b/selftest/lock_test/lock_test.sh
@@ -0,0 +1,55 @@
+#!/bin/sh
+
+owndir="$(dirname -- "$0")"
+
+echo 'creating files'
+dir="$(mktemp -d)"
+n1="long name"
+f1="$dir/$n1"
+touch "$f1"
+n2="shorter"
+f2="$dir/$n2"
+touch "$f2"
+sync
+
+echo 'launch a program that locks a given file, it will create $dir/lock_test'
+python3 $owndir/lock_test_help.py "$dir" "$n1" &
+
+echo 'wait until this lock_test lock file was created by program'
+while [ ! -f "$dir/lock_test" ]; do
+  sleep .1
+done
+sync
+
+echo 'expecting the lock file to reflect "long name"'
+echo "launched first, locked by: '$(cat "$dir/lock_test")'"
+
+echo 'launching second program, should find the lock intact and wait'
+python3 $owndir/lock_test_help.py "$dir" "$n2" &
+while [ ! -f "$f2.ready" ]; do
+  sleep .1
+done
+sleep 1
+sync
+echo "launched second, locked by: '$(cat "$dir/lock_test")'"
+
+echo 'drop the first lock, $f1 removal signals the first process to stop locking'
+rm "$f1"
+
+echo 'wait for first program to carry out the lock release'
+while [ ! -f "$f1.done" ]; do
+  sleep .1
+done
+
+echo 'now expecting second program to lock'
+echo "waited, locked by: '$(cat "$dir/lock_test")'"
+
+echo 'release the second program also'
+rm "$f2"
+while [ ! -f "$f2.done" ]; do
+  sleep .1
+done
+
+echo 'expecting the lock to be gone'
+echo "waited more, locked by: '$(cat "$dir/lock_test")'"
+rm -rf "$dir"