test: run mempool_compatibility.py even with wallet disabled

test/functional/mempool_compatibility.py

@@ -16,15 +16,15 @@ Only v0.15.2 is required by this test. The rest is used in other backwards compa
 import os
 
 from test_framework.test_framework import BitcoinTestFramework
+from test_framework.wallet import MiniWallet
 
 
 class MempoolCompatibilityTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 2
-        self.wallet_names = [None, self.default_wallet_name]
+        self.wallet_names = [None]
 
     def skip_test_if_missing_module(self):
-        self.skip_if_no_wallet()
         self.skip_if_no_previous_releases()
 
     def setup_network(self):
@@ -38,8 +38,15 @@ class MempoolCompatibilityTest(BitcoinTestFramework):
     def run_test(self):
         self.log.info("Test that mempool.dat is compatible between versions")
 
-        old_node = self.nodes[0]
-        new_node = self.nodes[1]
+        old_node, new_node = self.nodes
+        new_wallet = MiniWallet(new_node)
+        new_wallet.generate(1)
+        new_node.generate(100)
+        # Sync the nodes to ensure old_node has the block that contains the coinbase that new_wallet will spend.
+        # Otherwise, because coinbases are only valid in a block and not as loose txns, if the nodes aren't synced
+        # unbroadcasted_tx won't pass old_node's `MemPoolAccept::PreChecks`.
+        self.connect_nodes(0, 1)
+        self.sync_blocks()
         recipient = old_node.getnewaddress()
         self.stop_node(1)
 
@@ -58,7 +65,7 @@ class MempoolCompatibilityTest(BitcoinTestFramework):
         assert old_tx_hash in new_node.getrawmempool()
 
         self.log.info("Add unbroadcasted tx to mempool on new node and shutdown")
-        unbroadcasted_tx_hash = new_node.sendtoaddress(recipient, 0.0001)
+        unbroadcasted_tx_hash = new_wallet.send_self_transfer(from_node=new_node)['txid']
         assert unbroadcasted_tx_hash in new_node.getrawmempool()
         mempool = new_node.getrawmempool(True)
         assert mempool[unbroadcasted_tx_hash]['unbroadcast']