Use decoupled way for backend client

tests/test_backend_adapters.py

@@ -0,0 +1,150 @@
+import aiohttp
+import pytest
+
+from app.backend_adapters import (
+    HistoryDisabledBackendAdapter,
+    HttpBackendAdapter,
+    NullBackendAdapter,
+    build_backend_adapter,
+)
+
+
+@pytest.mark.asyncio
+async def test_build_backend_adapter_without_url_returns_null_adapter():
+    adapter = build_backend_adapter(
+        backend_url=None,
+        backend_mode="auto",
+        history_enabled=True,
+        timeout_sec=3,
+    )
+    assert isinstance(adapter, NullBackendAdapter)
+
+    assert await adapter.fetch_assistant_config("assistant_1") is None
+    assert (
+        await adapter.create_call_record(
+            user_id=1,
+            assistant_id="assistant_1",
+            source="debug",
+        )
+        is None
+    )
+    assert (
+        await adapter.add_transcript(
+            call_id="call_1",
+            turn_index=0,
+            speaker="human",
+            content="hi",
+            start_ms=0,
+            end_ms=100,
+            confidence=0.9,
+            duration_ms=100,
+        )
+        is False
+    )
+    assert (
+        await adapter.finalize_call_record(
+            call_id="call_1",
+            status="connected",
+            duration_seconds=2,
+        )
+        is False
+    )
+    assert await adapter.search_knowledge_context(kb_id="kb_1", query="hello", n_results=3) == []
+    assert await adapter.fetch_tool_resource("tool_1") is None
+
+
+@pytest.mark.asyncio
+async def test_http_backend_adapter_create_call_record_posts_expected_payload(monkeypatch):
+    captured = {}
+
+    class _FakeResponse:
+        def __init__(self, status=200, payload=None):
+            self.status = status
+            self._payload = payload if payload is not None else {}
+
+        async def __aenter__(self):
+            return self
+
+        async def __aexit__(self, exc_type, exc, tb):
+            return None
+
+        async def json(self):
+            return self._payload
+
+        def raise_for_status(self):
+            if self.status >= 400:
+                raise RuntimeError("http_error")
+
+    class _FakeClientSession:
+        def __init__(self, timeout=None):
+            captured["timeout"] = timeout
+
+        async def __aenter__(self):
+            return self
+
+        async def __aexit__(self, exc_type, exc, tb):
+            return None
+
+        def post(self, url, json=None):
+            captured["url"] = url
+            captured["json"] = json
+            return _FakeResponse(status=200, payload={"id": "call_123"})
+
+    monkeypatch.setattr("app.backend_adapters.aiohttp.ClientSession", _FakeClientSession)
+
+    adapter = build_backend_adapter(
+        backend_url="http://localhost:8100",
+        backend_mode="auto",
+        history_enabled=True,
+        timeout_sec=7,
+    )
+    assert isinstance(adapter, HttpBackendAdapter)
+
+    call_id = await adapter.create_call_record(
+        user_id=99,
+        assistant_id="assistant_9",
+        source="debug",
+    )
+
+    assert call_id == "call_123"
+    assert captured["url"] == "http://localhost:8100/api/history"
+    assert captured["json"] == {
+        "user_id": 99,
+        "assistant_id": "assistant_9",
+        "source": "debug",
+        "status": "connected",
+    }
+    assert isinstance(captured["timeout"], aiohttp.ClientTimeout)
+    assert captured["timeout"].total == 7
+
+
+@pytest.mark.asyncio
+async def test_backend_mode_disabled_forces_null_even_with_url():
+    adapter = build_backend_adapter(
+        backend_url="http://localhost:8100",
+        backend_mode="disabled",
+        history_enabled=True,
+        timeout_sec=7,
+    )
+    assert isinstance(adapter, NullBackendAdapter)
+
+
+@pytest.mark.asyncio
+async def test_history_disabled_wraps_backend_adapter():
+    adapter = build_backend_adapter(
+        backend_url="http://localhost:8100",
+        backend_mode="auto",
+        history_enabled=False,
+        timeout_sec=7,
+    )
+    assert isinstance(adapter, HistoryDisabledBackendAdapter)
+    assert await adapter.create_call_record(user_id=1, assistant_id="a1", source="debug") is None
+    assert await adapter.add_transcript(
+        call_id="c1",
+        turn_index=0,
+        speaker="human",
+        content="hi",
+        start_ms=0,
+        end_ms=10,
+        duration_ms=10,
+    ) is False