Add test for new StdAck From impl

Author: chipshort

packages/std/src/stdack.rs

@@ -166,4 +166,13 @@ mod tests {
         let ack2 = StdAck::error("kaputt");
         assert_eq!(ack2.to_binary(), br#"{"error":"kaputt"}"#);
     }
+
+    #[test]
+    fn stdack_to_option_binary_works() {
+        let ack1 = StdAck::success(b"\x01");
+        assert_eq!(Option::<Binary>::from(ack1.clone()), Some(ack1.to_binary()));
+
+        let ack2 = StdAck::error("kaputt");
+        assert_eq!(Option::<Binary>::from(ack2.clone()), Some(ack2.to_binary()));
+    }
 }