showcase wild cancel is fixed

deltachat-rpc-client/tests/test_wild_cancel.py

@@ -0,0 +1,59 @@
+"""Shows the IO restart spawned by `sync_transports()` cancelling the
+`receive_imf()` that is still processing the sync message,
+losing the `configured_addr` update and its `TransportsModified` event.
+"""
+
+from queue import Empty
+
+from deltachat_rpc_client import AttrDict, EventType
+
+EVENT_TIMEOUT = 10
+
+
+def next_event(account, timeout=EVENT_TIMEOUT):
+    try:
+        return AttrDict(account._rpc.get_queue(account.id).get(timeout=timeout))
+    except Empty:
+        return None
+
+
+def drain_events(account, quiet=1):
+    while next_event(account, quiet) is not None:
+        pass
+
+
+def wait_for_transports_modified(account):
+    """Return True on TRANSPORTS_MODIFIED, False once IO restarted without it.
+
+    Stopping IO awaits the inbox loop, so a completed restart means
+    the message is not being processed anymore and no event is coming.
+    """
+    while True:
+        event = next_event(account)
+        if event is None:
+            return False
+        if event.kind == EventType.TRANSPORTS_MODIFIED:
+            return True
+        # ": starting IO" also excludes the "restarting IO" that precedes it
+        if event.kind == EventType.INFO and event.msg.endswith(": starting IO"):
+            return False
+
+
+def test_wild_cancel_loses_primary_transport(acfactory):
+    ac1 = acfactory.get_online_account()
+    ac1_clone = ac1.clone()
+    ac1_clone.bring_online()
+
+    ac1.add_transport_from_qr(acfactory.get_account_qr())
+    [transport1, transport2] = ac1.list_transports()
+    assert wait_for_transports_modified(ac1_clone)
+    assert ac1_clone.get_config("configured_addr") == transport1["addr"]
+    drain_events(ac1_clone)
+
+    new_addr = transport2["addr"]
+    ac1.set_config("configured_addr", new_addr)
+    assert wait_for_transports_modified(ac1_clone)
+    second = wait_for_transports_modified(ac1_clone)
+    configured_addr = ac1_clone.get_config("configured_addr")
+    assert second, f"no second TRANSPORTS_MODIFIED, configured_addr={configured_addr!r}, expected {new_addr!r}"
+    assert configured_addr == new_addr