pytest: test failure if we crash after fundchannel_complete but before sendpsbt.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

tests/plugins/stop_sendpsbt.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+"""
+This plugin is used to shutdown a node before processing the sendpsbt command
+"""
+from pyln.client import Plugin
+import os
+import signal
+
+plugin = Plugin()
+
+
+@plugin.hook("rpc_command")
+def on_rpc_command(plugin, rpc_command, **kwargs):
+    request = rpc_command
+    if request["method"] == "sendpsbt":
+        os.kill(os.getppid(), signal.SIGKILL)
+
+    return {"result": "continue"}
+
+
+plugin.run()

tests/test_opening.py

@@ -2847,3 +2847,22 @@ def test_opening_crash(bitcoind, node_factory):
     l1.start()
 
     bitcoind.generate_block(1, wait_for_mempool=txid)
+
+
+@pytest.mark.xfail(strict=True)
+@pytest.mark.openchannel('v1')
+def test_sendpsbt_crash(bitcoind, node_factory):
+    """Stop sendpsbt, check it eventually opens"""
+    plugin_path = Path(__file__).parent / "plugins" / "stop_sendpsbt.py"
+    l1, l2 = node_factory.get_nodes(2, opts=[{"plugin": plugin_path, 'may_fail': True}, {}])
+
+    l1.fundwallet(3_000_000)
+    l1.connect(l2)
+
+    # signpsbt kills l1.
+    with pytest.raises(RpcError, match=r'Connection to RPC server lost.'):
+        l1.rpc.fundchannel(l2.info['id'], "2000000sat")
+
+    del l1.daemon.opts['plugin']
+    l1.start()
+    bitcoind.generate_block(1, wait_for_mempool=1)