fix parsing of peculiar multisig scripts, add tests on unknown scripts

btcpy/structs/script.py

@@ -699,14 +699,29 @@ class MultisigScript(ScriptPubKey):
 
     template = '<>+ OP_CHECKMULTISIG'
 
+    @classmethod
+    def verify(cls, bytes_):
+        from .crypto import PublicKey
+        parser = ScriptParser(bytes_)
+        if not bytes_:
+            raise WrongScriptTypeException('Empty script')
+        try:
+            m, *pubkeys, n = [data for data in parser.match(cls.template)]
+        except UnexpectedOperationFound as exc:
+            raise WrongScriptTypeException(str(exc))
+
+        if len(pubkeys) == 0 or len(pubkeys) != int(n):
+            raise WrongScriptTypeException('Non-matching N and number of pubkeys')
+
+        return [int(m), *[PublicKey(pubkey.data) for pubkey in pubkeys], int(n)]
+
     def __init__(self, *args):
         """
         :param args: if one arg is provided that is interpreted as a precompiled script which needs
         verification to see if it belongs to this type. Once verification is done, `m`, a list of pubkeys
         and `n` are extracted and saved.
         If more than one arg is provided, we assume that the parameters are `m, pubkey1, ..., pubkeyn, n`.
         """
-        from .crypto import PublicKey
 
         if len(args) == 0:
             raise TypeError('Wrong number of params for MultisigScript __init__: {}'.format(len(args)))
@@ -715,9 +730,6 @@ def __init__(self, *args):
             script = args[0]
             super().__init__(script.body)
             m, *pubkeys, n = self.verify(script.body)
-            m = int(m)
-            pubkeys = [PublicKey(pk.data) for pk in pubkeys]
-            n = int(n)
         else:
             m, *pubkeys, n = args
 

tests/data/unknownscripts.json

@@ -0,0 +1,17 @@
+["5152ae",
+ "6a",
+ "6a4b",
+ "6368",
+ "4bb175",
+ "4bb275",
+ "4bac",
+ "004b",
+ "a94b87",
+ "76a94b88ac",
+ "6a",
+ "ac",
+ "00",
+ "b175",
+ "b275",
+ "a987",
+ "76a988ac"]

tests/unit.py

@@ -36,6 +36,7 @@ def get_data(filename):
 
 transactions = get_data('rawtxs')
 scripts = get_data('scripts')
+unknownscripts = get_data('unknownscripts')
 keys = get_data('xkeys')
 segwit_valid_addresses = get_data('segwit_addr_valid')
 segwit_invalid_addresses = get_data('segwit_addr_invalid')
@@ -51,6 +52,14 @@ def get_data(filename):
 priv_pub_hash_addr_p2pkh_segwit = get_data('priv_pub_hash_addr_p2pkh_segwit')
 
 
+class TestUnknownScript(unittest.TestCase):
+
+    def test(self):
+        for script in unknownscripts:
+            result = ScriptBuilder.identify(unhexlify(script))
+            self.assertTrue(isinstance(result, UnknownScript))
+
+
 class TestPrivPubHashAddrP2pkhSegwit(unittest.TestCase):
 
     def test(self):