test: cover surviving mutants in libstackerdb + stacks-codec

libstackerdb/src/tests/mod.rs

@@ -23,6 +23,24 @@ use stacks_common::util::secp256k1::MessageSignature;
 
 use crate::*;
 
+#[test]
+fn test_stackerdb_chunk_data_consensus_codec_round_trip() {
+    let original = StackerDBChunkData {
+        slot_id: 0x0a0b0c0d,
+        slot_version: 0x11223344,
+        sig: MessageSignature([0xaa; 65]),
+        data: vec![0xde, 0xad, 0xbe, 0xef, 0x00, 0xff],
+    };
+    let bytes = original.serialize_to_vec();
+    // Empty / no-op serialize would leave bytes empty; the underflow check below traps that.
+    assert!(!bytes.is_empty(), "serialize must write bytes");
+    let decoded = StackerDBChunkData::consensus_deserialize(&mut &bytes[..]).unwrap();
+    assert_eq!(decoded.slot_id, original.slot_id);
+    assert_eq!(decoded.slot_version, original.slot_version);
+    assert_eq!(decoded.sig.0, original.sig.0);
+    assert_eq!(decoded.data, original.data);
+}
+
 #[test]
 fn test_stackerdb_slot_metadata_sign_verify() {
     let pk = StacksPrivateKey::random();
@@ -67,6 +85,27 @@ fn test_stackerdb_slot_metadata_sign_verify() {
     assert!(!bad_slot_metadata.verify(&addr).unwrap());
 }
 
+#[test]
+fn test_stackerdb_chunk_data_sign_verify() {
+    let pk = StacksPrivateKey::random();
+    let addr = StacksAddress::from_public_keys(
+        C32_ADDRESS_VERSION_MAINNET_SINGLESIG,
+        &AddressHashMode::SerializeP2PKH,
+        1,
+        &vec![StacksPublicKey::from_private(&pk)],
+    )
+    .unwrap();
+    let bad_addr = StacksAddress::new(0x01, Hash160([0x01; 20])).unwrap();
+
+    let mut chunk_data = StackerDBChunkData::new(7, 3, vec![0xab; 64]);
+    chunk_data.sign(&pk).unwrap();
+
+    // The chunk verifies against the address whose private key signed it.
+    assert!(chunk_data.verify(&addr).unwrap());
+    // The chunk does not verify against an unrelated address.
+    assert!(!chunk_data.verify(&bad_addr).unwrap());
+}
+
 #[test]
 fn test_stackerdb_paths() {
     let pk = StacksPrivateKey::from_hex(

stacks-codec/src/lib.rs

@@ -266,3 +266,54 @@ pub const PEER_ADDRESS_ENCODED_SIZE: u32 = 16;
 
 pub const HASH160_ENCODED_SIZE: u32 = 20;
 pub const MESSAGE_SIGNATURE_ENCODED_SIZE: u32 = 65;
+
+#[cfg(test)]
+mod tests {
+    use crate::*;
+
+    fn encode_vec_u32_len_prefix(len: u32, items: &[u32]) -> Vec<u8> {
+        let mut buf = Vec::with_capacity(4 + items.len() * 4);
+        buf.extend_from_slice(&len.to_be_bytes());
+        for x in items {
+            buf.extend_from_slice(&x.to_be_bytes());
+        }
+        buf
+    }
+
+    #[test]
+    fn read_next_at_most_enforces_length_bound() {
+        // len < max: succeeds with the decoded items.
+        let bytes = encode_vec_u32_len_prefix(3, &[10, 20, 30]);
+        let v: Vec<u32> = read_next_at_most(&mut &bytes[..], 5).unwrap();
+        assert_eq!(v, vec![10, 20, 30]);
+
+        // len == max: succeeds (the bound is inclusive: `len > max` is what rejects).
+        let bytes = encode_vec_u32_len_prefix(5, &[1, 2, 3, 4, 5]);
+        let v: Vec<u32> = read_next_at_most(&mut &bytes[..], 5).unwrap();
+        assert_eq!(v, vec![1, 2, 3, 4, 5]);
+
+        // len > max: errors with DeserializeError.
+        let bytes = encode_vec_u32_len_prefix(6, &[1, 2, 3, 4, 5, 6]);
+        let r: Result<Vec<u32>, Error> = read_next_at_most(&mut &bytes[..], 5);
+        assert!(
+            matches!(r, Err(Error::DeserializeError(_))),
+            "expected DeserializeError, got {r:?}"
+        );
+    }
+
+    #[test]
+    fn read_next_exact_enforces_exact_length() {
+        // len == num_items: succeeds.
+        let bytes = encode_vec_u32_len_prefix(5, &[1, 2, 3, 4, 5]);
+        let v: Vec<u32> = read_next_exact(&mut &bytes[..], 5).unwrap();
+        assert_eq!(v, vec![1, 2, 3, 4, 5]);
+
+        // len != num_items: errors.
+        let bytes = encode_vec_u32_len_prefix(3, &[10, 20, 30]);
+        let r: Result<Vec<u32>, Error> = read_next_exact(&mut &bytes[..], 5);
+        assert!(
+            matches!(r, Err(Error::DeserializeError(_))),
+            "expected DeserializeError, got {r:?}"
+        );
+    }
+}