From 3ea039684ee23f7890be86cb3c548a6f3e748751 Mon Sep 17 00:00:00 2001
From: 0xbyt4 <35742124+0xbyt4@users.noreply.github.com>
Date: Sun, 15 Mar 2026 13:48:56 +0300
Subject: [PATCH] test(voice): add integration tests with real NaCl crypto and
 Opus codec

End-to-end voice channel tests using real crypto (no mocks):

NaCl decrypt (5): valid packet, wrong key, bot SSRC, multi-packet, multi-SSRC
DAVE passthrough (3): unknown SSRC, Unencrypted error, real error drop
Full flow (5): utterance lifecycle, auto-map, pause/resume, corruption, cleanup
SPEAKING hook (4): hook installed, map/overwrite, mapped audio processed
Auth filtering (3): allowed user, rejected user, empty allowlist
Rejoin flow (3): clean state, new SSRC, missing SPEAKING auto-map
Multi-guild (2): independent receivers, stop isolation
Echo prevention (2): paused audio ignored, resumed audio processed
---
 tests/integration/test_voice_channel_flow.py | 611 +++++++++++++++++++
 1 file changed, 611 insertions(+)
 create mode 100644 tests/integration/test_voice_channel_flow.py

diff --git a/tests/integration/test_voice_channel_flow.py b/tests/integration/test_voice_channel_flow.py
new file mode 100644
index 000000000..096ef9d3f
--- /dev/null
+++ b/tests/integration/test_voice_channel_flow.py
@@ -0,0 +1,611 @@
+"""Integration tests for Discord voice channel audio flow.
+
+Uses real NaCl encryption and Opus codec (no mocks for crypto/codec).
+Does NOT require a Discord connection — tests the VoiceReceiver
+packet processing pipeline end-to-end.
+
+Requires: PyNaCl>=1.5.0, discord.py[voice] (opus codec)
+"""
+
+import struct
+import time
+import pytest
+
+pytestmark = pytest.mark.integration
+
+# Skip entire module if voice deps are missing
+pytest.importorskip("nacl.secret", reason="PyNaCl required for voice integration tests")
+discord = pytest.importorskip("discord", reason="discord.py required for voice integration tests")
+
+import nacl.secret
+
+try:
+    if not discord.opus.is_loaded():
+        import ctypes.util
+        opus_path = ctypes.util.find_library("opus")
+        if not opus_path:
+            import sys
+            for p in ("/opt/homebrew/lib/libopus.dylib", "/usr/local/lib/libopus.dylib"):
+                import os
+                if os.path.isfile(p):
+                    opus_path = p
+                    break
+        if opus_path:
+            discord.opus.load_opus(opus_path)
+    OPUS_AVAILABLE = discord.opus.is_loaded()
+except Exception:
+    OPUS_AVAILABLE = False
+
+from types import SimpleNamespace
+from unittest.mock import MagicMock
+from gateway.platforms.discord import VoiceReceiver
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+def _make_secret_key():
+    """Generate a random 32-byte key."""
+    import os
+    return os.urandom(32)
+
+
+def _build_encrypted_rtp_packet(secret_key, opus_payload, ssrc=100, seq=1, timestamp=960):
+    """Build a real NaCl-encrypted RTP packet matching Discord's format.
+
+    Format: RTP header (12 bytes) + encrypted(opus) + 4-byte nonce
+    Encryption: aead_xchacha20_poly1305 with RTP header as AAD.
+    """
+    # RTP header: version=2, payload_type=0x78, no extension, no CSRC
+    header = struct.pack(">BBHII", 0x80, 0x78, seq, timestamp, ssrc)
+
+    # Encrypt with NaCl AEAD
+    box = nacl.secret.Aead(secret_key)
+    nonce_counter = struct.pack(">I", seq)  # 4-byte counter as nonce seed
+    # Full 24-byte nonce: counter in first 4 bytes, rest zeros
+    full_nonce = nonce_counter + b'\x00' * 20
+
+    enc_msg = box.encrypt(opus_payload, header, full_nonce)
+    ciphertext = enc_msg.ciphertext  # without nonce prefix
+
+    # Discord format: header + ciphertext + 4-byte nonce
+    return header + ciphertext + nonce_counter
+
+
+def _make_voice_receiver(secret_key, dave_session=None, bot_ssrc=9999,
+                         allowed_user_ids=None, members=None):
+    """Create a VoiceReceiver with real secret key."""
+    vc = MagicMock()
+    vc._connection.secret_key = list(secret_key)
+    vc._connection.dave_session = dave_session
+    vc._connection.ssrc = bot_ssrc
+    vc._connection.add_socket_listener = MagicMock()
+    vc._connection.remove_socket_listener = MagicMock()
+    vc._connection.hook = None
+    vc.user = SimpleNamespace(id=bot_ssrc)
+    vc.channel = MagicMock()
+    vc.channel.members = members or []
+    receiver = VoiceReceiver(vc, allowed_user_ids=allowed_user_ids)
+    receiver.start()
+    return receiver
+
+
+# ---------------------------------------------------------------------------
+# Tests
+# ---------------------------------------------------------------------------
+
+
+class TestRealNaClDecrypt:
+    """End-to-end: real NaCl encrypt → _on_packet decrypt → buffer."""
+
+    def test_valid_encrypted_packet_buffered(self):
+        """Real NaCl encrypted packet → decrypted → buffered."""
+        key = _make_secret_key()
+        opus_silence = b'\xf8\xff\xfe'
+        receiver = _make_voice_receiver(key)
+
+        packet = _build_encrypted_rtp_packet(key, opus_silence, ssrc=100)
+        receiver._on_packet(packet)
+
+        assert 100 in receiver._buffers
+        assert len(receiver._buffers[100]) > 0
+
+    def test_wrong_key_packet_dropped(self):
+        """Packet encrypted with wrong key → NaCl fails → not buffered."""
+        real_key = _make_secret_key()
+        wrong_key = _make_secret_key()
+        opus_silence = b'\xf8\xff\xfe'
+        receiver = _make_voice_receiver(real_key)
+
+        packet = _build_encrypted_rtp_packet(wrong_key, opus_silence, ssrc=100)
+        receiver._on_packet(packet)
+
+        assert len(receiver._buffers.get(100, b"")) == 0
+
+    def test_bot_ssrc_ignored(self):
+        """Packet from bot's own SSRC → ignored."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key, bot_ssrc=9999)
+
+        packet = _build_encrypted_rtp_packet(key, b'\xf8\xff\xfe', ssrc=9999)
+        receiver._on_packet(packet)
+
+        assert len(receiver._buffers) == 0
+
+    def test_multiple_packets_accumulate(self):
+        """Multiple valid packets → buffer grows."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key)
+
+        for seq in range(1, 6):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver._on_packet(packet)
+
+        assert 100 in receiver._buffers
+        buf_size = len(receiver._buffers[100])
+        assert buf_size > 0, "Multiple packets should accumulate in buffer"
+
+    def test_different_ssrcs_separate_buffers(self):
+        """Packets from different SSRCs → separate buffers."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key)
+
+        for ssrc in [100, 200, 300]:
+            packet = _build_encrypted_rtp_packet(key, b'\xf8\xff\xfe', ssrc=ssrc)
+            receiver._on_packet(packet)
+
+        assert len(receiver._buffers) == 3
+        for ssrc in [100, 200, 300]:
+            assert ssrc in receiver._buffers
+
+
+class TestRealNaClWithDAVE:
+    """NaCl decrypt + DAVE passthrough scenarios with real crypto."""
+
+    def test_dave_unknown_ssrc_passthrough(self):
+        """DAVE enabled but SSRC unknown → skip DAVE, buffer audio."""
+        key = _make_secret_key()
+        dave = MagicMock()  # DAVE session present but SSRC not mapped
+        receiver = _make_voice_receiver(key, dave_session=dave)
+
+        packet = _build_encrypted_rtp_packet(key, b'\xf8\xff\xfe', ssrc=100)
+        receiver._on_packet(packet)
+
+        # DAVE decrypt not called (SSRC unknown)
+        dave.decrypt.assert_not_called()
+        # Audio still buffered via passthrough
+        assert 100 in receiver._buffers
+        assert len(receiver._buffers[100]) > 0
+
+    def test_dave_unencrypted_error_passthrough(self):
+        """DAVE raises 'Unencrypted' → use NaCl-decrypted data as-is."""
+        key = _make_secret_key()
+        dave = MagicMock()
+        dave.decrypt.side_effect = Exception(
+            "DecryptionFailed(UnencryptedWhenPassthroughDisabled)"
+        )
+        receiver = _make_voice_receiver(key, dave_session=dave)
+        receiver.map_ssrc(100, 42)
+
+        packet = _build_encrypted_rtp_packet(key, b'\xf8\xff\xfe', ssrc=100)
+        receiver._on_packet(packet)
+
+        # DAVE was called but failed → passthrough
+        dave.decrypt.assert_called_once()
+        assert 100 in receiver._buffers
+        assert len(receiver._buffers[100]) > 0
+
+    def test_dave_real_error_drops(self):
+        """DAVE raises non-Unencrypted error → packet dropped."""
+        key = _make_secret_key()
+        dave = MagicMock()
+        dave.decrypt.side_effect = Exception("KeyRotationFailed")
+        receiver = _make_voice_receiver(key, dave_session=dave)
+        receiver.map_ssrc(100, 42)
+
+        packet = _build_encrypted_rtp_packet(key, b'\xf8\xff\xfe', ssrc=100)
+        receiver._on_packet(packet)
+
+        assert len(receiver._buffers.get(100, b"")) == 0
+
+
+class TestFullVoiceFlow:
+    """End-to-end: encrypt → receive → buffer → silence detect → complete."""
+
+    def test_single_utterance_flow(self):
+        """Encrypt packets → buffer → silence → check_silence returns utterance."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key)
+        receiver.map_ssrc(100, 42)
+
+        # Send enough packets to exceed MIN_SPEECH_DURATION (0.5s)
+        # At 48kHz stereo 16-bit, each Opus silence frame decodes to ~3840 bytes
+        # Need 96000 bytes = ~25 frames
+        for seq in range(1, 30):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver._on_packet(packet)
+
+        # Simulate silence by setting last_packet_time in the past
+        receiver._last_packet_time[100] = time.monotonic() - 3.0
+
+        completed = receiver.check_silence()
+        assert len(completed) == 1
+        user_id, pcm_data = completed[0]
+        assert user_id == 42
+        assert len(pcm_data) > 0
+
+    def test_utterance_with_ssrc_automap(self):
+        """No SPEAKING event → auto-map sole allowed user → utterance processed."""
+        key = _make_secret_key()
+        members = [
+            SimpleNamespace(id=9999, name="Bot"),
+            SimpleNamespace(id=42, name="Alice"),
+        ]
+        receiver = _make_voice_receiver(
+            key, allowed_user_ids={"42"}, members=members
+        )
+        # No map_ssrc call — simulating missing SPEAKING event
+
+        for seq in range(1, 30):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver._on_packet(packet)
+
+        receiver._last_packet_time[100] = time.monotonic() - 3.0
+
+        completed = receiver.check_silence()
+        assert len(completed) == 1
+        assert completed[0][0] == 42  # auto-mapped to sole allowed user
+
+    def test_pause_blocks_during_playback(self):
+        """Pause receiver → packets ignored → resume → packets accepted."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key)
+
+        # Pause (echo prevention during TTS playback)
+        receiver.pause()
+        packet = _build_encrypted_rtp_packet(key, b'\xf8\xff\xfe', ssrc=100)
+        receiver._on_packet(packet)
+        assert len(receiver._buffers.get(100, b"")) == 0
+
+        # Resume
+        receiver.resume()
+        receiver._on_packet(packet)
+        assert 100 in receiver._buffers
+        assert len(receiver._buffers[100]) > 0
+
+    def test_corrupted_packet_ignored(self):
+        """Corrupted/truncated packet → silently ignored."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key)
+
+        # Too short
+        receiver._on_packet(b"\x00" * 5)
+        assert len(receiver._buffers) == 0
+
+        # Wrong RTP version
+        bad_header = struct.pack(">BBHII", 0x00, 0x78, 1, 960, 100)
+        receiver._on_packet(bad_header + b"\x00" * 20)
+        assert len(receiver._buffers) == 0
+
+        # Wrong payload type
+        bad_pt = struct.pack(">BBHII", 0x80, 0x00, 1, 960, 100)
+        receiver._on_packet(bad_pt + b"\x00" * 20)
+        assert len(receiver._buffers) == 0
+
+    def test_stop_cleans_everything(self):
+        """stop() clears all state cleanly."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key)
+        receiver.map_ssrc(100, 42)
+
+        for seq in range(1, 10):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver._on_packet(packet)
+
+        assert len(receiver._buffers[100]) > 0
+
+        receiver.stop()
+        assert receiver._running is False
+        assert len(receiver._buffers) == 0
+        assert len(receiver._ssrc_to_user) == 0
+        assert len(receiver._decoders) == 0
+
+
+class TestSPEAKINGHook:
+    """SPEAKING event hook correctly maps SSRC to user_id."""
+
+    def test_speaking_hook_installed(self):
+        """start() installs speaking hook on connection."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key)
+        conn = receiver._vc._connection
+        # hook should be set (wrapped)
+        assert conn.hook is not None
+
+    def test_map_ssrc_via_speaking(self):
+        """SPEAKING op 5 event maps SSRC to user_id."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key)
+        receiver.map_ssrc(500, 12345)
+        assert receiver._ssrc_to_user[500] == 12345
+
+    def test_map_ssrc_overwrites(self):
+        """New SPEAKING event for same SSRC overwrites old mapping."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key)
+        receiver.map_ssrc(500, 111)
+        receiver.map_ssrc(500, 222)
+        assert receiver._ssrc_to_user[500] == 222
+
+    def test_speaking_mapped_audio_processed(self):
+        """After SSRC is mapped, audio from that SSRC gets correct user_id."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key)
+        receiver.map_ssrc(100, 42)
+
+        for seq in range(1, 30):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver._on_packet(packet)
+
+        receiver._last_packet_time[100] = time.monotonic() - 3.0
+        completed = receiver.check_silence()
+        assert len(completed) == 1
+        assert completed[0][0] == 42
+
+
+class TestAuthFiltering:
+    """Only allowed users' audio should be processed."""
+
+    def test_allowed_user_audio_processed(self):
+        """Allowed user's utterance is returned by check_silence."""
+        key = _make_secret_key()
+        members = [
+            SimpleNamespace(id=9999, name="Bot"),
+            SimpleNamespace(id=42, name="Alice"),
+        ]
+        receiver = _make_voice_receiver(
+            key, allowed_user_ids={"42"}, members=members,
+        )
+        receiver.map_ssrc(100, 42)
+
+        for seq in range(1, 30):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver._on_packet(packet)
+
+        receiver._last_packet_time[100] = time.monotonic() - 3.0
+        completed = receiver.check_silence()
+        assert len(completed) == 1
+        assert completed[0][0] == 42
+
+    def test_automap_rejects_unallowed_user(self):
+        """Auto-map refuses to map SSRC to user not in allowed list."""
+        key = _make_secret_key()
+        members = [
+            SimpleNamespace(id=9999, name="Bot"),
+            SimpleNamespace(id=42, name="Alice"),
+        ]
+        receiver = _make_voice_receiver(
+            key, allowed_user_ids={"99"},  # Alice not allowed
+            members=members,
+        )
+        # No map_ssrc — SSRC unknown, auto-map should reject
+
+        for seq in range(1, 30):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver._on_packet(packet)
+
+        receiver._last_packet_time[100] = time.monotonic() - 3.0
+        completed = receiver.check_silence()
+        assert len(completed) == 0
+
+    def test_empty_allowlist_allows_all(self):
+        """Empty allowed_user_ids means no restriction."""
+        key = _make_secret_key()
+        members = [
+            SimpleNamespace(id=9999, name="Bot"),
+            SimpleNamespace(id=42, name="Alice"),
+        ]
+        receiver = _make_voice_receiver(
+            key, allowed_user_ids=None, members=members,
+        )
+
+        for seq in range(1, 30):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver._on_packet(packet)
+
+        receiver._last_packet_time[100] = time.monotonic() - 3.0
+        completed = receiver.check_silence()
+        # Auto-mapped to sole non-bot member
+        assert len(completed) == 1
+        assert completed[0][0] == 42
+
+
+class TestRejoinFlow:
+    """Leave and rejoin: state cleanup and fresh receiver."""
+
+    def test_stop_then_new_receiver_clean_state(self):
+        """After stop(), a new receiver starts with empty state."""
+        key = _make_secret_key()
+        receiver1 = _make_voice_receiver(key)
+        receiver1.map_ssrc(100, 42)
+
+        for seq in range(1, 10):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver1._on_packet(packet)
+
+        assert len(receiver1._buffers[100]) > 0
+        receiver1.stop()
+
+        # New receiver (simulates rejoin)
+        receiver2 = _make_voice_receiver(key)
+        assert len(receiver2._buffers) == 0
+        assert len(receiver2._ssrc_to_user) == 0
+        assert len(receiver2._decoders) == 0
+
+    def test_rejoin_new_ssrc_works(self):
+        """After rejoin, user may get new SSRC — still works."""
+        key = _make_secret_key()
+        receiver1 = _make_voice_receiver(key)
+        receiver1.map_ssrc(100, 42)  # old SSRC
+        receiver1.stop()
+
+        receiver2 = _make_voice_receiver(key)
+        receiver2.map_ssrc(200, 42)  # new SSRC after rejoin
+
+        for seq in range(1, 30):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=200, seq=seq, timestamp=960 * seq
+            )
+            receiver2._on_packet(packet)
+
+        receiver2._last_packet_time[200] = time.monotonic() - 3.0
+        completed = receiver2.check_silence()
+        assert len(completed) == 1
+        assert completed[0][0] == 42
+
+    def test_rejoin_without_speaking_event_automap(self):
+        """Rejoin without SPEAKING event — auto-map sole allowed user."""
+        key = _make_secret_key()
+        members = [
+            SimpleNamespace(id=9999, name="Bot"),
+            SimpleNamespace(id=42, name="Alice"),
+        ]
+
+        # First session
+        receiver1 = _make_voice_receiver(
+            key, allowed_user_ids={"42"}, members=members,
+        )
+        receiver1.stop()
+
+        # Rejoin — new key (Discord may assign new secret_key)
+        new_key = _make_secret_key()
+        receiver2 = _make_voice_receiver(
+            new_key, allowed_user_ids={"42"}, members=members,
+        )
+        # No map_ssrc — simulating missing SPEAKING event
+
+        for seq in range(1, 30):
+            packet = _build_encrypted_rtp_packet(
+                new_key, b'\xf8\xff\xfe', ssrc=300, seq=seq, timestamp=960 * seq
+            )
+            receiver2._on_packet(packet)
+
+        receiver2._last_packet_time[300] = time.monotonic() - 3.0
+        completed = receiver2.check_silence()
+        assert len(completed) == 1
+        assert completed[0][0] == 42
+
+
+class TestMultiGuildIsolation:
+    """Each guild has independent voice state."""
+
+    def test_separate_receivers_independent(self):
+        """Two receivers (different guilds) don't interfere."""
+        key1 = _make_secret_key()
+        key2 = _make_secret_key()
+
+        receiver1 = _make_voice_receiver(key1, bot_ssrc=1111)
+        receiver2 = _make_voice_receiver(key2, bot_ssrc=2222)
+
+        receiver1.map_ssrc(100, 42)
+        receiver2.map_ssrc(200, 99)
+
+        # Send to receiver1
+        for seq in range(1, 10):
+            packet = _build_encrypted_rtp_packet(
+                key1, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver1._on_packet(packet)
+
+        # receiver2 should be empty
+        assert len(receiver2._buffers) == 0
+        assert 100 in receiver1._buffers
+
+    def test_stop_one_doesnt_affect_other(self):
+        """Stopping one receiver doesn't affect another."""
+        key1 = _make_secret_key()
+        key2 = _make_secret_key()
+
+        receiver1 = _make_voice_receiver(key1)
+        receiver2 = _make_voice_receiver(key2)
+
+        receiver1.map_ssrc(100, 42)
+        receiver2.map_ssrc(200, 99)
+
+        for seq in range(1, 10):
+            packet = _build_encrypted_rtp_packet(
+                key2, b'\xf8\xff\xfe', ssrc=200, seq=seq, timestamp=960 * seq
+            )
+            receiver2._on_packet(packet)
+
+        receiver1.stop()
+
+        # receiver2 still has data
+        assert receiver2._running is True
+        assert len(receiver2._buffers[200]) > 0
+
+
+class TestEchoPreventionFlow:
+    """Receiver pause/resume during TTS playback prevents echo."""
+
+    def test_audio_during_pause_ignored(self):
+        """Audio arriving while paused is completely ignored."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key)
+        receiver.map_ssrc(100, 42)
+        receiver.pause()
+
+        for seq in range(1, 30):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver._on_packet(packet)
+
+        assert len(receiver._buffers.get(100, b"")) == 0
+
+    def test_audio_after_resume_processed(self):
+        """Audio arriving after resume is processed normally."""
+        key = _make_secret_key()
+        receiver = _make_voice_receiver(key)
+        receiver.map_ssrc(100, 42)
+
+        # Pause → send packets → resume → send more packets
+        receiver.pause()
+        for seq in range(1, 5):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver._on_packet(packet)
+        assert len(receiver._buffers.get(100, b"")) == 0
+
+        receiver.resume()
+        for seq in range(5, 35):
+            packet = _build_encrypted_rtp_packet(
+                key, b'\xf8\xff\xfe', ssrc=100, seq=seq, timestamp=960 * seq
+            )
+            receiver._on_packet(packet)
+
+        assert len(receiver._buffers[100]) > 0
+        receiver._last_packet_time[100] = time.monotonic() - 3.0
+        completed = receiver.check_silence()
+        assert len(completed) == 1
+        assert completed[0][0] == 42