Use separate watchonly wallet for multisig in feature_nulldummy.py

Create and import the multisig into a separate watchonly wallet so that
feature_nulldummy.py works with descriptor wallets.

blocktools.create_raw_transaction is also updated to use multiple nodes
and wallets and to use PSBT so that this test passes.

Author: achow101

test/functional/feature_nulldummy.py

@@ -51,10 +51,18 @@ def skip_test_if_missing_module(self):
         self.skip_if_no_wallet()
 
     def run_test(self):
-        self.address = self.nodes[0].getnewaddress()
-        self.ms_address = self.nodes[0].addmultisigaddress(1, [self.address])['address']
-        self.wit_address = self.nodes[0].getnewaddress(address_type='p2sh-segwit')
-        self.wit_ms_address = self.nodes[0].addmultisigaddress(1, [self.address], '', 'p2sh-segwit')['address']
+        self.nodes[0].createwallet(wallet_name='wmulti', disable_private_keys=True)
+        wmulti = self.nodes[0].get_wallet_rpc('wmulti')
+        w0 = self.nodes[0].get_wallet_rpc(self.default_wallet_name)
+        self.address = w0.getnewaddress()
+        self.pubkey = w0.getaddressinfo(self.address)['pubkey']
+        self.ms_address = wmulti.addmultisigaddress(1, [self.pubkey])['address']
+        self.wit_address = w0.getnewaddress(address_type='p2sh-segwit')
+        self.wit_ms_address = wmulti.addmultisigaddress(1, [self.pubkey], '', 'p2sh-segwit')['address']
+        if not self.options.descriptors:
+            # Legacy wallets need to import these so that they are watched by the wallet. This is unnecssary (and does not need to be tested) for descriptor wallets
+            wmulti.importaddress(self.ms_address)
+            wmulti.importaddress(self.wit_ms_address)
 
         self.coinbase_blocks = self.nodes[0].generate(2)  # Block 2
         coinbase_txid = []

test/functional/test_framework/blocktools.py

@@ -162,9 +162,8 @@ def create_tx_with_script(prevtx, n, script_sig=b"", *, amount, script_pub_key=C
 
 def create_transaction(node, txid, to_address, *, amount):
     """ Return signed transaction spending the first output of the
-        input txid. Note that the node must be able to sign for the
-        output that is being spent, and the node must not be running
-        multiple wallets.
+        input txid. Note that the node must have a wallet that can
+        sign for the output that is being spent.
     """
     raw_tx = create_raw_transaction(node, txid, to_address, amount=amount)
     tx = CTransaction()
@@ -173,14 +172,18 @@ def create_transaction(node, txid, to_address, *, amount):
 
 def create_raw_transaction(node, txid, to_address, *, amount):
     """ Return raw signed transaction spending the first output of the
-        input txid. Note that the node must be able to sign for the
-        output that is being spent, and the node must not be running
-        multiple wallets.
+        input txid. Note that the node must have a wallet that can sign
+        for the output that is being spent.
     """
-    rawtx = node.createrawtransaction(inputs=[{"txid": txid, "vout": 0}], outputs={to_address: amount})
-    signresult = node.signrawtransactionwithwallet(rawtx)
-    assert_equal(signresult["complete"], True)
-    return signresult['hex']
+    psbt = node.createpsbt(inputs=[{"txid": txid, "vout": 0}], outputs={to_address: amount})
+    for _ in range(2):
+        for w in node.listwallets():
+            wrpc = node.get_wallet_rpc(w)
+            signed_psbt = wrpc.walletprocesspsbt(psbt)
+            psbt = signed_psbt['psbt']
+    final_psbt = node.finalizepsbt(psbt)
+    assert_equal(final_psbt["complete"], True)
+    return final_psbt['hex']
 
 def get_legacy_sigopcount_block(block, accurate=True):
     count = 0