diff --git a/services/commtest/src/tools.rs b/services/commtest/src/tools.rs
new file mode 100644
--- /dev/null
+++ b/services/commtest/src/tools.rs
@@ -0,0 +1,7 @@
+pub fn generate_nbytes(n: usize, c: Option<u8>) -> Vec<u8> {
+  let c : u8 = match c {
+    Some(c) => c,
+    None => b'A',
+  };
+  return vec![c; n];
+}