Merge #20385: test: run mempool_spend_coinbase.py even with wallet disabled

21f2433601 test: run mempool_spend_coinbase.py even with wallet disabled (Michael Dietz)

Pull request description:

  Run the mempool spend coinbase test even when the wallet was not compiled, as proposed in #20078.

ACKs for top commit:
  laanwj:
    ACK 21f2433601

Tree-SHA512: 301582c04376371cfa8f1ebb2418a4341b42ddcd9ad4f48b58bcf888d867a97bdc409972856b67a8339ac5e60124aefee82a049b4f7fc6bca7a18d7e92e090be

test/functional/test_framework/wallet.py

@@ -40,9 +40,20 @@ class MiniWallet:
             self._utxos.append({'txid': cb_tx['txid'], 'vout': 0, 'value': cb_tx['vout'][0]['value']})
         return blocks
 
-    def get_utxo(self):
-        """Return the last utxo. Can be used to get the change output immediately after a send_self_transfer"""
-        return self._utxos.pop()
+    def get_utxo(self, *, txid=''):
+        """
+        Returns a utxo and marks it as spent (pops it from the internal list)
+
+        Args:
+        txid (string), optional: get the first utxo we find from a specific transaction
+
+        Note: Can be used to get the change output immediately after a send_self_transfer
+        """
+        index = -1  # by default the last utxo
+        if txid:
+            utxo = next(filter(lambda utxo: txid == utxo['txid'], self._utxos))
+            index = self._utxos.index(utxo)
+        return self._utxos.pop(index)
 
     def send_self_transfer(self, *, fee_rate=Decimal("0.003"), from_node, utxo_to_spend=None):
         """Create and send a tx with the specified fee_rate. Fee may be exact or at most one satoshi higher than needed."""