test: Updates needed after bitcoin-core/libmultiprocess#240

diff --git a/test/functional/interface_ipc.py b/test/functional/interface_ipc.py
index f90f72b0..1e279e00 100755
--- a/test/functional/interface_ipc.py
+++ b/test/functional/interface_ipc.py
@@ -4,8 +4,6 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test the IPC (multiprocess) interface."""
 import asyncio
-import http.client
-import re
 
 from contextlib import ExitStack
 from test_framework.test_framework import BitcoinTestFramework
@@ -86,9 +84,9 @@ class IPCInterfaceTest(BitcoinTestFramework):
 
     def run_unclean_disconnect_test(self):
         """Test behavior when disconnecting during an IPC call that later
-        returns a non-null interface pointer. Currently this behavior causes a
-        crash as reported https://github.com/bitcoin/bitcoin/issues/34250, but a
-        followup will change this behavior."""
+        returns a non-null interface pointer. This used to cause a crash as
+        reported https://github.com/bitcoin/bitcoin/issues/34250, but now just
+        results in a cancellation log message"""
         node = self.nodes[0]
         self.log.info("Running disconnect during BlockTemplate.waitNext")
         timeout = self.rpc_timeout * 1000.0
@@ -110,28 +108,22 @@ class IPCInterfaceTest(BitcoinTestFramework):
             with node.assert_debug_log(expected_msgs=["BlockTemplate.waitNext", "IPC server post request"], timeout=2):
                 promise = template.waitNext(ctx, waitoptions)
                 await asyncio.sleep(0.1)
-            disconnected_log_check.enter_context(node.assert_debug_log(expected_msgs=["IPC server: socket disconnected"], timeout=2))
+            disconnected_log_check.enter_context(node.assert_debug_log(expected_msgs=["IPC server: socket disconnected", "canceled while executing"], timeout=2))
             del promise
 
         asyncio.run(capnp.run(async_routine()))
 
         # Wait for socket disconnected log message, then generate a block to
-        # cause the waitNext() call to return a new template. This will cause a
-        # crash and disconnect with error output.
-        disconnected_log_check.close()
-        try:
+        # cause the waitNext() call to return a new template. Look for a
+        # canceled IPC log message after waitNext returns.
+        with node.assert_debug_log(expected_msgs=["interrupted (canceled)"], timeout=2):
+            disconnected_log_check.close()
             self.generate(node, 1)
-        except (http.client.RemoteDisconnected, BrokenPipeError, ConnectionResetError):
-            pass
-        node.wait_until_stopped(expected_ret_code=(-11, -6, 1, 66), expected_stderr=re.compile(""))
-        self.start_node(0)
 
     def run_thread_busy_test(self):
         """Test behavior when sending multiple calls to the same server thread
         which used to cause a crash as reported
-        https://github.com/bitcoin/bitcoin/issues/33923 and currently causes a
-        thread busy error. A future change will make this just queue the calls
-        for execution and not trigger any error"""
+        https://github.com/bitcoin/bitcoin/issues/33923."""
         node = self.nodes[0]
         self.log.info("Running thread busy test")
         timeout = self.rpc_timeout * 1000.0
@@ -151,27 +143,26 @@ class IPCInterfaceTest(BitcoinTestFramework):
             waitoptions.feeThreshold = 1
 
             # Make multiple waitNext calls where the first will start to
-            # execute, the second will be posted waiting to execute, and the
-            # third will fail to execute because the execution thread is busy.
+            # execute, and the second and third will be posted waiting to
+            # execute. Previously, the third call would fail calling
+            # mp::Waiter::post() because the waiting function slot is occupied,
+            # but now posts are queued.
             with node.assert_debug_log(expected_msgs=["BlockTemplate.waitNext", "IPC server post request"], timeout=2):
                 promise1 = template.waitNext(ctx, waitoptions)
                 await asyncio.sleep(0.1)
             with node.assert_debug_log(expected_msgs=["BlockTemplate.waitNext", "IPC server post request"], timeout=2):
                 promise2 = template.waitNext(ctx, waitoptions)
                 await asyncio.sleep(0.1)
-            try:
-                await template.waitNext(ctx, waitoptions)
-            except capnp.lib.capnp.KjException as e:
-                assert_equal(e.description, "remote exception: std::exception: thread busy")
-                assert_equal(e.type, "FAILED")
-            else:
-                raise AssertionError("Expected thread busy exception")
+            with node.assert_debug_log(expected_msgs=["BlockTemplate.waitNext", "IPC server post request"], timeout=2):
+                promise3 = template.waitNext(ctx, waitoptions)
+                await asyncio.sleep(0.1)
 
             # Generate a new block to make the active waitNext calls return, then clean up.
             with node.assert_debug_log(expected_msgs=["IPC server send response"], timeout=2):
                 self.generate(node, 1, sync_fun=self.no_op)
             await ((await promise1).result).destroy(ctx)
             await ((await promise2).result).destroy(ctx)
+            await ((await promise3).result).destroy(ctx)
             await template.destroy(ctx)
 
         asyncio.run(capnp.run(async_routine()))
diff --git a/test/functional/interface_ipc_mining.py b/test/functional/interface_ipc_mining.py
index 2221d462..72919b0c 100755
--- a/test/functional/interface_ipc_mining.py
+++ b/test/functional/interface_ipc_mining.py
@@ -6,7 +6,7 @@
 import asyncio
 from contextlib import AsyncExitStack
 from io import BytesIO
-import re
+import platform
 from test_framework.blocktools import NULL_OUTPOINT
 from test_framework.messages import (
     MAX_BLOCK_WEIGHT,
@@ -245,17 +245,15 @@ class IPCMiningTest(BitcoinTestFramework):
                 await mining.createNewBlock(ctx, opts)
                 raise AssertionError("createNewBlock unexpectedly succeeded")
             except capnp.lib.capnp.KjException as e:
-                if e.type == "DISCONNECTED":
-                    # The remote exception isn't caught currently and leads to a
-                    # std::terminate call. Just detect and restart in this case.
-                    # This bug is fixed with
-                    # https://github.com/bitcoin-core/libmultiprocess/pull/218
-                    assert_equal(e.description, "Peer disconnected.")
-                    self.nodes[0].wait_until_stopped(expected_ret_code=(-11, -6, 1, 66), expected_stderr=re.compile(""))
-                    self.start_node(0)
+                if e.description == "remote exception: unknown non-KJ exception of type: kj::Exception":
+                    # macOS + REDUCE_EXPORTS bug: Cap'n Proto fails to recognize
+                    # its own exception type and returns a generic error instead.
+                    # https://github.com/bitcoin/bitcoin/pull/34422#discussion_r2863852691
+                    # Assert this only occurs on Darwin until fixed.
+                    assert_equal(platform.system(), "Darwin")
                 else:
                     assert_equal(e.description, "remote exception: std::exception: block_reserved_weight (0) must be at least 2000 weight units")
-                    assert_equal(e.type, "FAILED")
+                assert_equal(e.type, "FAILED")
 
         asyncio.run(capnp.run(async_routine()))