Add GTL price-traffic chart diagnostic

tests/unit/test_sr_levels_router.py

@@ -3,7 +3,6 @@
 from datetime import datetime
 from unittest.mock import AsyncMock, patch
 
-import pytest
 from fastapi import FastAPI
 from fastapi.testclient import TestClient
 
@@ -29,10 +28,12 @@ class _FakeLevel:
 
 
 class _FakeOHLCV:
-    """Mimics an OHLCVRecord with a close attribute."""
+    """Mimics an OHLCVRecord with price attributes."""
 
-    def __init__(self, close: float):
+    def __init__(self, close: float, high: float | None = None, low: float | None = None):
         self.close = close
+        self.high = high if high is not None else close + 1.0
+        self.low = low if low is not None else close - 1.0
 
 
 def _make_app() -> FastAPI:
@@ -62,6 +63,71 @@ SAMPLE_LEVELS = [
 SAMPLE_OHLCV = [_FakeOHLCV(100.0)]
 
 
+class TestGateTargetLadderRouter:
+    @patch("app.routers.sr_levels.detect_gate_target_ladder")
+    @patch("app.routers.sr_levels.query_ohlcv", new_callable=AsyncMock)
+    def test_returns_transient_price_traffic_proposals(self, mock_ohlcv, mock_detect):
+        mock_ohlcv.return_value = [
+            _FakeOHLCV(100.0, high=101.0, low=99.0),
+            _FakeOHLCV(102.0, high=103.0, low=100.0),
+        ]
+        mock_detect.return_value = [
+            {
+                "price_level": 105.0,
+                "type": "resistance",
+                "strength": 80,
+                "detection_method": "merged",
+                "sources": ["pivot_point", "range_grid"],
+                "rejection_count": 7,
+            },
+            {
+                "price_level": 95.0,
+                "type": "support",
+                "strength": 60,
+                "detection_method": "range_grid",
+                "sources": ["range_grid"],
+                "rejection_count": 4,
+            },
+        ]
+
+        response = TestClient(_make_app()).get("/api/v1/gate-target-ladder/aapl")
+
+        assert response.status_code == 200
+        data = response.json()["data"]
+        assert data["symbol"] == "AAPL"
+        assert data["lookback_bars"] == 2
+        assert [level["price_level"] for level in data["levels"]] == [95.0, 105.0]
+        assert data["levels"][1] == {
+            "price_level": 105.0,
+            "type": "resistance",
+            "strength": 80,
+            "detection_method": "merged",
+            "sources": ["pivot_point", "range_grid"],
+            "traffic_count": 7,
+        }
+        mock_detect.assert_called_once_with(
+            [101.0, 103.0],
+            [99.0, 100.0],
+            [100.0, 102.0],
+        )
+
+    @patch("app.routers.sr_levels.detect_gate_target_ladder")
+    @patch("app.routers.sr_levels.query_ohlcv", new_callable=AsyncMock)
+    def test_empty_history_returns_empty_ladder(self, mock_ohlcv, mock_detect):
+        mock_ohlcv.return_value = []
+
+        response = TestClient(_make_app()).get("/api/v1/gate-target-ladder/AAPL")
+
+        assert response.status_code == 200
+        assert response.json()["data"] == {
+            "symbol": "AAPL",
+            "levels": [],
+            "count": 0,
+            "lookback_bars": 0,
+        }
+        mock_detect.assert_not_called()
+
+
 class TestSRLevelsRouterZones:
     """Tests for max_zones parameter and zone inclusion in response."""
 
@@ -207,7 +273,7 @@ class TestSRLevelsRouterVisibleLevels:
             ), f"visible level price {price} not within any zone bounds"
 
         # visible_levels must be a subset of levels (by id)
-        level_ids = {l["id"] for l in data["levels"]}
+        level_ids = {level["id"] for level in data["levels"]}
         for lvl in visible:
             assert lvl["id"] in level_ids