[PATCH BlueZ v2 3/3] test: Cover A2DP disconnection during SetConfiguration

[Luiz Augusto von Dentz <luiz.dentz@gmail.com>]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Add test_a2dp_disconnect_during_setconf, where the source disconnects
while the sink endpoint has not replied to SetConfiguration yet, and
the late reply, either accepting or rejecting, must be ignored and the
stream configured again on reconnection.

Assisted-by: Claude:claude-opus-5-5
---
 doc/functional-a2dp.rst      | 37 +++++++++++++++++++++++
 test/functional/test_a2dp.py | 58 ++++++++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+)

diff --git a/doc/functional-a2dp.rst b/doc/functional-a2dp.rst
index 03b18a7201c2..f38a458bb7c2 100644
--- a/doc/functional-a2dp.rst
+++ b/doc/functional-a2dp.rst
@@ -97,3 +97,40 @@ test_a2dp_transport_acquire
 
 :Notes: Acquiring on the source side starts the stream, so the
 	peripheral does not have to acquire its own transport.
+
+test_a2dp_disconnect_during_setconf[accept|reject]
+--------------------------------------------------
+
+:Setup: As above, except the peripheral registers its A2DP Sink
+	endpoint manually with ``Auto Accept: no``, so that `bluetoothd`
+	is left waiting for the reply to
+	``org.bluez.MediaEndpoint1.SetConfiguration``.
+
+:Steps:
+	1. Pair and trust as above.
+	2. Central: ``connect <peripheral bdaddr>``.
+	3. Peripheral: wait for the ``Accept (yes/no):`` prompt, without
+	   answering it.
+	4. Central: ``disconnect <peripheral bdaddr>``.
+	5. Peripheral: answer the pending prompt with ``yes``
+	   (``accept``) or ``no`` (``reject``).
+	6. Central: ``connect <peripheral bdaddr>`` again, and the
+	   peripheral answers ``yes`` to the new prompt.
+
+:Expected:
+	1. ``Pairing successful`` and ``trust succeeded`` on both hosts.
+	2. The peripheral receives ``Endpoint: SetConfiguration``.
+	3. The prompt is shown.
+	4. ``Disconnection successful`` on the central, and the transport
+	   created on the peripheral for the pending configuration is
+	   removed (``[DEL] Transport``).
+	5. The late reply is ignored.
+	6. ``Connection successful``, and a transport appears on both
+	   hosts.
+
+:Notes: Regression test for a crash of `bluetoothd` on the peripheral:
+	the setup of the pending configuration outlived the AVDTP session
+	and the late reply dereferenced a NULL session in
+	``auto_config()``. A late ``yes`` used to also leave the stale
+	transport registered, failing the next connection with
+	``Resource temporarily unavailable``.
diff --git a/test/functional/test_a2dp.py b/test/functional/test_a2dp.py
index 1ab712cd0da1..12348ea05ae2 100644
--- a/test/functional/test_a2dp.py
+++ b/test/functional/test_a2dp.py
@@ -142,3 +142,61 @@ def test_a2dp_transport_acquire(a2dp_hosts):
     source.expect(r"Acquire successful: fd \d+ MTU \d+:\d+")
 
     source.expect(f"Transport {transport} State: active")
+
+
+def start_bluetoothctl_manual_sink(host):
+    """
+    Start bluetoothctl registering an A2DP Sink endpoint that does not
+    auto accept, so that SetConfiguration is left pending until the
+    Accept prompt is answered.
+    """
+    exe = find_exe("client", "bluetoothctl")
+    ctl = host.pexpect.spawn([exe])
+
+    ctl.send("power on\n")
+    ctl.expect("Changing power on succeeded")
+
+    ctl.send(f"endpoint.register {A2DP_SINK_UUID} 0x00\n")
+    ctl.expect(r"Auto Accept \(yes/no\):")
+    ctl.send("no\n")
+    ctl.expect(r"Max Transports \(auto/value\):")
+    ctl.send("a\n")
+    ctl.expect("Endpoint /local/endpoint/ep0 registered")
+    return ctl
+
+
+@pytest.mark.parametrize("reply", ["accept", "reject"])
+@a2dp_host_config
+def test_a2dp_disconnect_during_setconf(hosts, reply):
+    host0, host1 = hosts
+
+    source = start_bluetoothctl(host0, "a2dp-source-sbc.bt")
+    sink = start_bluetoothctl_manual_sink(host1)
+
+    pair(host0, source, host1, sink)
+
+    # Leave SetConfiguration pending on the sink
+    source.send(f"connect {host1.bdaddr}\n")
+    sink.expect("Endpoint: SetConfiguration")
+    _, m = sink.expect(TRANSPORT_RE)
+    transport = m[0].decode("utf-8")
+    sink.expect(r"Accept \(yes/no\):")
+
+    source.send(f"disconnect {host1.bdaddr}\n")
+    source.expect("Disconnection successful")
+
+    # The pending configuration is cleared on disconnection
+    # [DEL] is colored, so match around the escape sequences
+    sink.expect(rf"DEL\S*\] Transport {transport}")
+
+    # Late reply must be ignored
+    sink.send("yes\n" if reply == "accept" else "no\n")
+
+    # bluetoothd is still alive and the stream can be configured again
+    source.send(f"connect {host1.bdaddr}\n")
+    sink.expect("Endpoint: SetConfiguration")
+    sink.expect(TRANSPORT_RE)
+    sink.expect(r"Accept \(yes/no\):")
+    sink.send("yes\n")
+    source.expect("Connection successful")
+    source.expect(TRANSPORT_RE)
-- 
2.55.0