Merge #712: fix len check in blech32 decode() in test framework

522a147 Add blech32 roundtrip test for python implementation (Gregory Sanders)
32564b0 fix len check in blech32 decode() in test framework (Dmitry Petukhov)

Pull request description:

  I used the code from test/functional/test_framework/liquid_addr.py with the same length check adjustments in python-elementstx to decode Liquid's blech32 addresses, and it seems to be working fine.

Tree-SHA512: 4ac4589e0cdbeb7397a4f3c9000b8fdb91516ca257b757cddbfb6df2d75df4587ddcee37b8f9f1d0364d5e78515ea2e1f4270eecca42ea9a59b8f28578d7ab1c

Author: instagibbs

test/functional/feature_confidential_transactions.py

@@ -28,6 +28,11 @@
 import os
 import re
 
+from test_framework.liquid_addr import (
+    encode,
+    decode,
+)
+
 class CTTest (BitcoinTestFramework):
 
     def set_test_params(self):
@@ -104,6 +109,15 @@ def run_test(self):
         print("Testing wallet secret recovery")
         self.test_wallet_recovery()
 
+        print("Test blech32 python roundtrip")
+        # blech/bech are aliased, both are blech32
+        for addrtype in ["bech32", "blech32"]:
+            addr_to_rt = self.nodes[0].getnewaddress("", addrtype)
+            hrp = addr_to_rt[:2]
+            assert_equal(hrp, "el")
+            (witver, witprog) = decode(hrp, addr_to_rt)
+            assert_equal(encode(hrp, witver, witprog), addr_to_rt)
+
         # Test that "blech32" gives a blinded segwit address.
         blech32_addr = self.nodes[0].getnewaddress("", "blech32")
         blech32_addr_info = self.nodes[0].getaddressinfo(blech32_addr)

test/functional/test_framework/liquid_addr.py

@@ -84,16 +84,19 @@ def convertbits(data, frombits, tobits, pad=True):
 
 
 def decode(hrp, addr):
-    """Decode a segwit address."""
+    """Decode a segwit confidential address.
+    Its payload is longer than the payload for unconfidential address
+    by 33 bytes (the length of blinding pubkey)"""
+
     hrpgot, data = blech32_decode(addr)
     if hrpgot != hrp:
         return (None, None)
     decoded = convertbits(data[1:], 5, 8, False)
-    if decoded is None or len(decoded) < 2 or len(decoded) > 40:
+    if decoded is None or len(decoded) < 2 or len(decoded) > 40+33:
         return (None, None)
     if data[0] > 16:
         return (None, None)
-    if data[0] == 0 and len(decoded) != 20 and len(decoded) != 32:
+    if data[0] == 0 and len(decoded) != 20+33 and len(decoded) != 32+33:
         return (None, None)
     return (data[0], decoded)