I finally got around to looking at vodozemac. I'm not impressed. At least it took more than 30 seconds this time.
diff --git a/src/olm/shared_secret.rs b/src/olm/shared_secret.rs
index ebad928..e0edfc6 100644
--- a/src/olm/shared_secret.rs
+++ b/src/olm/shared_secret.rs
@@ -154,4 +154,101 @@ mod test {