Add Twilio call queue service with channel allocation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_twilio_service.py

@@ -0,0 +1,67 @@
+import sys
+sys.path.insert(0, "/Users/lukemacneil/ai-podcast")
+
+from backend.services.twilio_service import TwilioService
+
+
+def test_queue_starts_empty():
+    svc = TwilioService()
+    assert svc.get_queue() == []
+
+
+def test_add_caller_to_queue():
+    svc = TwilioService()
+    svc.add_to_queue("CA123", "+15125550142")
+    q = svc.get_queue()
+    assert len(q) == 1
+    assert q[0]["call_sid"] == "CA123"
+    assert q[0]["phone"] == "+15125550142"
+    assert "wait_time" in q[0]
+
+
+def test_remove_caller_from_queue():
+    svc = TwilioService()
+    svc.add_to_queue("CA123", "+15125550142")
+    svc.remove_from_queue("CA123")
+    assert svc.get_queue() == []
+
+
+def test_allocate_channel():
+    svc = TwilioService()
+    ch1 = svc.allocate_channel()
+    ch2 = svc.allocate_channel()
+    assert ch1 == 3
+    assert ch2 == 4
+    svc.release_channel(ch1)
+    ch3 = svc.allocate_channel()
+    assert ch3 == 3
+
+
+def test_take_call():
+    svc = TwilioService()
+    svc.add_to_queue("CA123", "+15125550142")
+    result = svc.take_call("CA123")
+    assert result["call_sid"] == "CA123"
+    assert result["channel"] >= 3
+    assert svc.get_queue() == []
+    assert svc.active_calls["CA123"]["channel"] == result["channel"]
+
+
+def test_hangup_real_caller():
+    svc = TwilioService()
+    svc.add_to_queue("CA123", "+15125550142")
+    svc.take_call("CA123")
+    ch = svc.active_calls["CA123"]["channel"]
+    svc.hangup("CA123")
+    assert "CA123" not in svc.active_calls
+    assert ch not in svc._allocated_channels
+
+
+def test_caller_counter_increments():
+    svc = TwilioService()
+    svc.add_to_queue("CA1", "+15125550001")
+    svc.add_to_queue("CA2", "+15125550002")
+    r1 = svc.take_call("CA1")
+    r2 = svc.take_call("CA2")
+    assert r1["name"] == "Caller #1"
+    assert r2["name"] == "Caller #2"