Merge bitcoin/bitcoin#32033: test: Check datadir cleanup after assumeutxo was successful

52482cb test: Check datadir cleanup after assumeutxo was successful (Fabian Jahr)

Pull request description:

  I noticed that the proper datadir cleanup after a successful restart of an assumutxo node does not seem to be covered in our tests. This is added here.

ACKs for top commit:
  l0rinc:
    utACK 52482cb
  mabu44:
    Re-ACK 52482cb
  Prabhat1308:
    re-ACK [`52482cb`](bitcoin/bitcoin@52482cb)
  TheCharlatan:
    Re-ACK 52482cb

Tree-SHA512: cc941afeba250050eaccf5112255d961253fec9b2683545454a0d2fbe4d542178394b301d169a9dd79edbf6b5d478d95282727dbb0aca96ee79d4cd1ff80f19b

Author: hebasto

test/functional/feature_assumeutxo.py

@@ -9,6 +9,7 @@
 The assumeutxo value generated and used here is committed to in
 `CRegTestParams::m_assumeutxo_data` in `src/kernel/chainparams.cpp`.
 """
+import contextlib
 from shutil import rmtree
 
 from dataclasses import dataclass
@@ -349,6 +350,22 @@ def assert_only_network_limited_service(self, node):
         assert 'NETWORK' not in node_services
         assert 'NETWORK_LIMITED' in node_services
 
+    @contextlib.contextmanager
+    def assert_disk_cleanup(self, node, assumeutxo_used):
+        """
+        Ensure an assumeutxo node is cleaning up the background chainstate
+        """
+        msg = []
+        if assumeutxo_used:
+            # Check that the snapshot actually existed before restart
+            assert (node.datadir_path / node.chain / "chainstate_snapshot").exists()
+            msg = ["cleaning up unneeded background chainstate"]
+
+        with node.assert_debug_log(msg):
+            yield
+
+        assert not (node.datadir_path / node.chain / "chainstate_snapshot").exists()
+
     def run_test(self):
         """
         Bring up two (disconnected) nodes, mine some new blocks on the first,
@@ -656,7 +673,8 @@ def check_tx_counts(final: bool) -> None:
         for i in (0, 1):
             n = self.nodes[i]
             self.log.info(f"Restarting node {i} to ensure (Check|Load)BlockIndex passes")
-            self.restart_node(i, extra_args=self.extra_args[i])
+            with self.assert_disk_cleanup(n, i == 1):
+                self.restart_node(i, extra_args=self.extra_args[i])
 
             assert_equal(n.getblockchaininfo()["blocks"], FINAL_HEIGHT)
 
@@ -733,7 +751,8 @@ def check_tx_counts(final: bool) -> None:
         for i in (0, 2):
             n = self.nodes[i]
             self.log.info(f"Restarting node {i} to ensure (Check|Load)BlockIndex passes")
-            self.restart_node(i, extra_args=self.extra_args[i])
+            with self.assert_disk_cleanup(n, i == 2):
+                self.restart_node(i, extra_args=self.extra_args[i])
 
             assert_equal(n.getblockchaininfo()["blocks"], FINAL_HEIGHT)