diff --git a/serdect/tests/bincode.rs b/serdect/tests/bincode.rs
index e4a39ccea..9b5035051 100644
--- a/serdect/tests/bincode.rs
+++ b/serdect/tests/bincode.rs
@@ -7,10 +7,11 @@ use proptest::{array::*, collection::vec, prelude::*};
 use serdect::{array, slice};
 
 /// Example input to be serialized.
-const EXAMPLE_BYTES: [u8; 16] = hex!("000102030405060708090A0B0C0D0E0F");
+/// Last byte is `0xFF` to test that no packing is performed for values under 128.
+const EXAMPLE_BYTES: [u8; 16] = hex!("000102030405060708090A0B0C0D0EFF");
 
 /// bincode serialization of [`EXAMPLE_BYTES`] as a slice.
-const BINCODE_SLICE: [u8; 24] = hex!("1000000000000000000102030405060708090A0B0C0D0E0F");
+const BINCODE_SLICE: [u8; 24] = hex!("1000000000000000000102030405060708090A0B0C0D0EFF");
 
 /// bincode serialization of [`EXAMPLE_BYTES`] as an array.
 const BINCODE_ARRAY: [u8; 16] = EXAMPLE_BYTES;
diff --git a/serdect/tests/cbor.rs b/serdect/tests/cbor.rs
index a4173c69e..ea2d71ad7 100644
--- a/serdect/tests/cbor.rs
+++ b/serdect/tests/cbor.rs
@@ -9,15 +9,16 @@ use serde::Serialize;
 use serdect::{array, slice};
 
 /// Example input to be serialized.
-const EXAMPLE_BYTES: [u8; 16] = hex!("000102030405060708090A0B0C0D0E0F");
+/// Last byte is `0xFF` to test that no packing is performed for values under 128.
+const EXAMPLE_BYTES: [u8; 16] = hex!("000102030405060708090A0B0C0D0EFF");
 
 /// CBOR serialization of [`EXAMPLE_BYTES`] as a slice.
 /// (first three bits, `0b010` denote a byte string, and the last five, `0b10000` denote the length)
-const CBOR_SLICE: [u8; 17] = hex!("50000102030405060708090A0B0C0D0E0F");
+const CBOR_SLICE: [u8; 17] = hex!("50000102030405060708090A0B0C0D0EFF");
 
 /// CBOR serialization of [`EXAMPLE_BYTES`] as an array.
 /// (first three bits, `0b100` denote an array, and the last five, `0b10000` denote the length)
-const CBOR_ARRAY: [u8; 17] = hex!("90000102030405060708090A0B0C0D0E0F");
+const CBOR_ARRAY: [u8; 17] = hex!("90000102030405060708090A0B0C0D0EFF");
 
 #[test]
 fn deserialize_slice() {