Add traffic telemetry export

backend/tests/test_e2e.py

@@ -64,3 +64,64 @@ async def test_api_analytics():
         data = res.json()
         assert "total_requests" in data
         assert "savings" in data
+
+
+@pytest.mark.asyncio
+async def test_api_traffic_export_json_contains_audit_fields():
+    transport = ASGITransport(app=app)
+    async with AsyncClient(transport=transport, base_url="http://test") as client:
+        generate_res = await client.post(
+            "/api/generate",
+            json={"prompt": "Write a Python function for a traffic export"},
+        )
+        assert generate_res.status_code == 200
+
+        export_res = await client.get("/api/traffic/export?format=json")
+
+    assert export_res.status_code == 200
+    assert export_res.headers["content-type"].startswith("application/json")
+    assert "attachment" in export_res.headers["content-disposition"]
+    records = export_res.json()
+    assert records
+    assert {
+        "timestamp",
+        "request_id",
+        "prompt_preview",
+        "task_type",
+        "complexity",
+        "selected_model",
+        "input_tokens",
+        "output_tokens",
+        "total_tokens",
+        "cost_saved",
+        "total_latency_ms",
+    }.issubset(records[0])
+
+
+@pytest.mark.asyncio
+async def test_api_traffic_export_csv_returns_downloadable_rows():
+    transport = ASGITransport(app=app)
+    async with AsyncClient(transport=transport, base_url="http://test") as client:
+        generate_res = await client.post(
+            "/api/generate",
+            json={"prompt": "Summarize this traffic record"},
+        )
+        assert generate_res.status_code == 200
+
+        export_res = await client.get("/api/traffic/export?format=csv")
+
+    assert export_res.status_code == 200
+    assert export_res.headers["content-type"].startswith("text/csv")
+    assert "traffic-export.csv" in export_res.headers["content-disposition"]
+    lines = export_res.text.splitlines()
+    assert lines[0].startswith("timestamp,request_id,prompt_preview,")
+    assert len(lines) >= 2
+
+
+@pytest.mark.asyncio
+async def test_api_traffic_export_rejects_unknown_format():
+    transport = ASGITransport(app=app)
+    async with AsyncClient(transport=transport, base_url="http://test") as client:
+        export_res = await client.get("/api/traffic/export?format=xml")
+
+    assert export_res.status_code == 422