diff --git a/services/commtest/tests/lib/tools.rs b/services/commtest/tests/lib/tools.rs
new file mode 100644
--- /dev/null
+++ b/services/commtest/tests/lib/tools.rs
@@ -0,0 +1,19 @@
+use bytesize::ByteSize;
+
+#[allow(dead_code)]
+pub fn generate_nbytes(number_of_bytes: usize, predefined_byte_value: Option<u8>) -> Vec<u8> {
+  let byte_value = predefined_byte_value.unwrap_or(b'A');
+  return vec![byte_value; number_of_bytes];
+}
+
+#[derive(
+  Debug, derive_more::Display, derive_more::From, derive_more::Error,
+)]
+pub enum Error {
+  #[display(...)]
+  Proto(std::io::Error),
+  #[display(...)]
+  Tonic(tonic::transport::Error),
+  #[display(...)]
+  TonicStatus(tonic::Status),
+}