test:Validate UTXO snapshot with coin_height > base_height & amount > money_supply

You can use this tool to decode the utxo snapshot https://github.com/jrakibi/utxo-live
Here’s an overview of how it’s done:
The serialization forma for a UTXO in the snapshot is as follows:
1. Transaction ID (txid) - 32 bytes
2. Output Index (outnum)- 4 bytes
3. VARINT (code) - A varible-length integer encoding the height and whether the transaction is a coinbase. The format of this VARINT is (height << 1) | coinbase_flag.
4. VARINT (amount_v) - A variable-length integer that represents a compressed format of the output amount (in satoshis).

For the test cases mentioned:
* b"\x84\x58" - This value corresponds to a VARINT representing the height and coinbase flag. Once we decode this code, we can extract the height and coinbase using height = code_decoded >> 1 and coinbase = code_decoded & 0x01. In our case, with code_decoded = 728, it results in height = 364 and coinbase = 0.
* b"\xCA\xD2\x8F\x5A" - This byte sequence represents a compressed amount value. The decompression function takes this value and translates it into a full amount in satoshis. In our case, the decompression of this amount translates to a number larger than the maximum allowed value of coins (21 million BTC)

test:Validate UTXO snapshot with coin_height > base_height & amount > money_supply

test:Validate UTXO snapshot with coin_height > base_height & amount > money_supply

1 files changed, 11 insertions, 8 deletions

diff --git a/test/functional/feature_assumeutxo.py b/test/functional/feature_assumeutxo.py
index 19cbbcffdb..2842d82d80 100755
--- a/test/functional/feature_assumeutxo.py
+++ b/test/functional/feature_assumeutxo.py
@@ -13,8 +13,6 @@ The assumeutxo value generated and used here is committed to in
 
 Interesting test cases could be loading an assumeutxo snapshot file with:
 
-- TODO: Valid hash but invalid snapshot file (bad coin height or
-      bad other serialization)
 - TODO: Valid snapshot file, but referencing a snapshot block that turns out to be
       invalid, or has an invalid parent
 - TODO: Valid snapshot file and snapshot block, but the block is not on the
@@ -98,18 +96,23 @@ class AssumeutxoTest(BitcoinTestFramework):
 
         self.log.info("  - snapshot file with alternated UTXO data")
         cases = [
-            [b"\xff" * 32, 0, "7d52155c9a9fdc4525b637ef6170568e5dad6fabd0b1fdbb9432010b8453095b"],  # wrong outpoint hash
-            [(1).to_bytes(4, "little"), 32, "9f4d897031ab8547665b4153317ae2fdbf0130c7840b66427ebc48b881cb80ad"],  # wrong outpoint index
-            [b"\x81", 36, "3da966ba9826fb6d2604260e01607b55ba44e1a5de298606b08704bc62570ea8"],  # wrong coin code VARINT((coinbase ? 1 : 0) | (height << 1))
-            [b"\x80", 36, "091e893b3ccb4334378709578025356c8bcb0a623f37c7c4e493133c988648e5"],  # another wrong coin code
+            # (content, offset, wrong_hash, custom_message)
+            [b"\xff" * 32, 0, "7d52155c9a9fdc4525b637ef6170568e5dad6fabd0b1fdbb9432010b8453095b", None],  # wrong outpoint hash
+            [(1).to_bytes(4, "little"), 32, "9f4d897031ab8547665b4153317ae2fdbf0130c7840b66427ebc48b881cb80ad", None],  # wrong outpoint index
+            [b"\x81", 36, "3da966ba9826fb6d2604260e01607b55ba44e1a5de298606b08704bc62570ea8", None],  # wrong coin code VARINT
+            [b"\x80", 36, "091e893b3ccb4334378709578025356c8bcb0a623f37c7c4e493133c988648e5", None],  # another wrong coin code
+            [b"\x84\x58", 36, None, "[snapshot] bad snapshot data after deserializing 0 coins"],  # wrong coin case with height 364 and coinbase 0
+            [b"\xCA\xD2\x8F\x5A", 41, None, "[snapshot] bad snapshot data after deserializing 0 coins - bad tx out value"],  # Amount exceeds MAX_MONEY
         ]
 
-        for content, offset, wrong_hash in cases:
+        for content, offset, wrong_hash, custom_message in cases:
             with open(bad_snapshot_path, "wb") as f:
                 f.write(valid_snapshot_contents[:(32 + 8 + offset)])
                 f.write(content)
                 f.write(valid_snapshot_contents[(32 + 8 + offset + len(content)):])
-            expected_error(log_msg=f"[snapshot] bad snapshot content hash: expected a4bf3407ccb2cc0145c49ebba8fa91199f8a3903daf0883875941497d2493c27, got {wrong_hash}")
+
+            log_msg = custom_message if custom_message is not None else f"[snapshot] bad snapshot content hash: expected a4bf3407ccb2cc0145c49ebba8fa91199f8a3903daf0883875941497d2493c27, got {wrong_hash}"
+            expected_error(log_msg=log_msg)
 
     def test_headers_not_synced(self, valid_snapshot_path):
         for node in self.nodes[1:]: