test: run mempool_spend_coinbase.py even with wallet disabled

test/functional/mempool_spend_coinbase.py

@@ -13,44 +13,48 @@ but less mature coinbase spends are NOT.
 """
 
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.blocktools import create_raw_transaction
 from test_framework.util import assert_equal, assert_raises_rpc_error
+from test_framework.wallet import MiniWallet
 
 
 class MempoolSpendCoinbaseTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 1
-
-    def skip_test_if_missing_module(self):
-        self.skip_if_no_wallet()
+        self.setup_clean_chain = True
 
     def run_test(self):
+        wallet = MiniWallet(self.nodes[0])
+
+        wallet.generate(200)
         chain_height = self.nodes[0].getblockcount()
         assert_equal(chain_height, 200)
-        node0_address = self.nodes[0].getnewaddress()
 
         # Coinbase at height chain_height-100+1 ok in mempool, should
         # get mined. Coinbase at height chain_height-100+2 is
-        # is too immature to spend.
+        # too immature to spend.
         b = [self.nodes[0].getblockhash(n) for n in range(101, 103)]
         coinbase_txids = [self.nodes[0].getblock(h)['tx'][0] for h in b]
-        spends_raw = [create_raw_transaction(self.nodes[0], txid, node0_address, amount=49.99) for txid in coinbase_txids]
+        utxo_101 = wallet.get_utxo(txid=coinbase_txids[0])
+        utxo_102 = wallet.get_utxo(txid=coinbase_txids[1])
 
-        spend_101_id = self.nodes[0].sendrawtransaction(spends_raw[0])
+        spend_101_id = wallet.send_self_transfer(from_node=self.nodes[0], utxo_to_spend=utxo_101)["txid"]
 
         # coinbase at height 102 should be too immature to spend
-        assert_raises_rpc_error(-26,"bad-txns-premature-spend-of-coinbase", self.nodes[0].sendrawtransaction, spends_raw[1])
+        assert_raises_rpc_error(-26,
+                                "bad-txns-premature-spend-of-coinbase",
+                                lambda: wallet.send_self_transfer(from_node=self.nodes[0], utxo_to_spend=utxo_102))
 
         # mempool should have just spend_101:
-        assert_equal(self.nodes[0].getrawmempool(), [ spend_101_id ])
+        assert_equal(self.nodes[0].getrawmempool(), [spend_101_id])
 
         # mine a block, spend_101 should get confirmed
         self.nodes[0].generate(1)
         assert_equal(set(self.nodes[0].getrawmempool()), set())
 
         # ... and now height 102 can be spent:
-        spend_102_id = self.nodes[0].sendrawtransaction(spends_raw[1])
-        assert_equal(self.nodes[0].getrawmempool(), [ spend_102_id ])
+        spend_102_id = wallet.send_self_transfer(from_node=self.nodes[0], utxo_to_spend=utxo_102)["txid"]
+        assert_equal(self.nodes[0].getrawmempool(), [spend_102_id])
+
 
 if __name__ == '__main__':
     MempoolSpendCoinbaseTest().main()

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."""