Refactor codebase following Clean Code principles and add 229 tests

- Extract helpers to reduce function sizes (listing_tasks, app.py, query.py, listing_fetcher)
  - Replace nonlocal mutations with _PipelineState dataclass in listing_tasks
  - Fix bugs: isinstance→equality check in repository, verify_exp for OIDC tokens
  - Consolidate duplicate filter methods in listing_repository
  - Move hardcoded config to env vars with backward-compatible defaults
  - Simplify CLI decorator to auto-build QueryParameters
  - Add deprecation docstring to data_access.py
  - Test count: 158 → 387 (all passing)

crawler/tests/integration/test_api.py

@@ -1,5 +1,6 @@
 """Integration tests for API endpoints."""
-from unittest.mock import AsyncMock, patch
+import json
+from unittest.mock import AsyncMock, MagicMock, patch
 import pytest
 from httpx import AsyncClient
 
@@ -75,10 +76,12 @@ class TestListingGeoJsonEndpoint:
         self, async_client: AsyncClient
     ) -> None:
         """Test that listing_geojson accepts filter parameters."""
+        mock_result = MagicMock()
+        mock_result.data = {"type": "FeatureCollection", "features": []}
         with patch(
-            "api.app.export_immoweb",
+            "api.app.export_service.export_to_geojson",
             new_callable=AsyncMock,
-            return_value={"type": "FeatureCollection", "features": []},
+            return_value=mock_result,
         ):
             response = await async_client.get(
                 "/api/listing_geojson",
@@ -178,3 +181,135 @@ class TestTaskStatusEndpoint:
             )
             # Should return 401 or 403 without valid auth
             assert response.status_code in (401, 403)
+
+
+class TestStreamListingGeoJsonEndpoint:
+    """Tests for the /api/listing_geojson/stream endpoint."""
+
+    async def test_stream_returns_ndjson_with_metadata(
+        self, async_client: AsyncClient
+    ) -> None:
+        """Test that the stream endpoint returns valid NDJSON starting with a metadata message."""
+        fake_features = [
+            {"type": "Feature", "properties": {"id": 1}, "geometry": {"type": "Point", "coordinates": [0, 0]}},
+            {"type": "Feature", "properties": {"id": 2}, "geometry": {"type": "Point", "coordinates": [1, 1]}},
+        ]
+
+        with patch("api.app.get_cached_count", return_value=2), \
+             patch("api.app.get_cached_features", return_value=iter([fake_features])):
+            response = await async_client.get(
+                "/api/listing_geojson/stream",
+                params={"listing_type": "RENT", "batch_size": 50},
+            )
+            assert response.status_code == 200
+            assert response.headers["content-type"] == "application/x-ndjson"
+
+            lines = [line for line in response.text.strip().split("\n") if line]
+            assert len(lines) >= 2  # at least metadata + complete
+
+            metadata = json.loads(lines[0])
+            assert metadata["type"] == "metadata"
+            assert "batch_size" in metadata
+            assert "total_expected" in metadata
+
+            complete = json.loads(lines[-1])
+            assert complete["type"] == "complete"
+            assert "total" in complete
+
+    async def test_stream_cache_hit_path(
+        self, async_client: AsyncClient
+    ) -> None:
+        """Test that cache-hit path returns cached: True in metadata."""
+        fake_features = [
+            {"type": "Feature", "properties": {"id": 1}, "geometry": {"type": "Point", "coordinates": [0, 0]}},
+        ]
+
+        with patch("api.app.get_cached_count", return_value=1), \
+             patch("api.app.get_cached_features", return_value=iter([fake_features])):
+            response = await async_client.get(
+                "/api/listing_geojson/stream",
+                params={"listing_type": "RENT"},
+            )
+            assert response.status_code == 200
+            lines = [line for line in response.text.strip().split("\n") if line]
+            metadata = json.loads(lines[0])
+            assert metadata["cached"] is True
+            assert metadata["total_expected"] == 1
+
+            batch_msg = json.loads(lines[1])
+            assert batch_msg["type"] == "batch"
+            assert len(batch_msg["features"]) == 1
+
+    async def test_stream_cache_miss_path(
+        self, async_client: AsyncClient
+    ) -> None:
+        """Test that cache-miss path queries DB and returns cached: False."""
+        from datetime import datetime
+
+        fake_rows = [
+            {
+                "id": 100,
+                "price": 2000.0,
+                "number_of_bedrooms": 2,
+                "square_meters": 50.0,
+                "longitude": -0.1,
+                "latitude": 51.5,
+                "photo_thumbnail": None,
+                "last_seen": datetime(2024, 1, 1),
+                "agency": "Test Agency",
+                "price_history_json": "[]",
+                "available_from": None,
+            },
+        ]
+
+        mock_repo = MagicMock()
+        mock_repo.count_listings.return_value = 1
+        mock_repo.stream_listings_optimized.return_value = iter(fake_rows)
+
+        with patch("api.app.get_cached_count", return_value=None), \
+             patch("api.app.ListingRepository", return_value=mock_repo), \
+             patch("api.app.cache_features_batch"):
+            response = await async_client.get(
+                "/api/listing_geojson/stream",
+                params={"listing_type": "RENT"},
+            )
+            assert response.status_code == 200
+            lines = [line for line in response.text.strip().split("\n") if line]
+
+            metadata = json.loads(lines[0])
+            assert metadata["cached"] is False
+            assert metadata["total_expected"] == 1
+
+            batch_msg = json.loads(lines[1])
+            assert batch_msg["type"] == "batch"
+            assert len(batch_msg["features"]) == 1
+            assert batch_msg["features"][0]["type"] == "Feature"
+            assert batch_msg["features"][0]["properties"]["total_price"] == 2000.0
+
+            complete = json.loads(lines[-1])
+            assert complete["type"] == "complete"
+            assert complete["total"] == 1
+
+    async def test_stream_with_limit(
+        self, async_client: AsyncClient
+    ) -> None:
+        """Test that the limit parameter caps the number of streamed features."""
+        fake_features = [
+            {"type": "Feature", "properties": {"id": i}, "geometry": {"type": "Point", "coordinates": [0, 0]}}
+            for i in range(5)
+        ]
+
+        with patch("api.app.get_cached_count", return_value=5), \
+             patch("api.app.get_cached_features", return_value=iter([fake_features])):
+            response = await async_client.get(
+                "/api/listing_geojson/stream",
+                params={"listing_type": "RENT", "limit": 3},
+            )
+            assert response.status_code == 200
+            lines = [line for line in response.text.strip().split("\n") if line]
+            metadata = json.loads(lines[0])
+            assert metadata["total_expected"] == 3
+
+            complete = json.loads(lines[-1])
+            assert complete["type"] == "complete"
+            assert complete["total"] == 3