diff --git a/packages/cultnet-ts/test/rudp-send-failure.test.ts b/packages/cultnet-ts/test/rudp-send-failure.test.ts
index 803b1e15..3078dbf7 100644
--- a/packages/cultnet-ts/test/rudp-send-failure.test.ts
+++ b/packages/cultnet-ts/test/rudp-send-failure.test.ts
@@ -281,8 +281,8 @@ test("an operation call the network refuses rejects with a timeout and does not
           serviceId: "service",
           operation: "operation",
           payloadSchema: "payload",
-          payloadEncoding: "messagepack",
-          payload: new Uint8Array(),
+          payloadEncoding: "messagepack-base64",
+          payload: "gaZzY2hlbWE=",
           diagnostics: [],
           sourceRuntimeId: "caller",
         },
@@ -402,8 +402,8 @@ test("an operation server ignores a send failure reported after the generation t
     serviceId: "service",
     operation: "operation",
     payloadSchema: "payload",
-    payloadEncoding: "messagepack",
-    payload: new Uint8Array(),
+    payloadEncoding: "messagepack-base64",
+    payload: "gaZzY2hlbWE=",
     diagnostics: [],
     sourceRuntimeId: "caller",
   } satisfies CultNetOperationRequestMessage, "cultnet.schema.v0")), { reliable: true, ordered: true, nowMs: Date.now() });