Add vector change detection foundation

backend/tests/test_sprint18_change_detection.py

@@ -0,0 +1,163 @@
+from __future__ import annotations
+
+from datetime import datetime, timezone
+from uuid import uuid4
+
+from fastapi.testclient import TestClient
+from geoalchemy2.shape import from_shape
+from shapely.geometry import box
+
+from app.db.session import get_db
+from app.main import app
+from app.models import Dataset, Job, VectorFeature
+from app.schemas.analysis import ChangeDetectionSummary
+from app.services.change_detection_service import ChangeDetectionService
+
+
+class FakeQuery:
+    def __init__(self, rows):
+        self.rows = list(rows)
+
+    def filter(self, *criteria):
+        for criterion in criteria:
+            left = getattr(criterion, "left", None)
+            right = getattr(criterion, "right", None)
+            operator = getattr(criterion, "operator", None)
+            name = getattr(left, "name", None)
+            value = getattr(right, "value", right)
+            if name and operator and operator.__name__ == "eq":
+                self.rows = [row for row in self.rows if getattr(row, name) == value]
+        return self
+
+    def all(self):
+        return list(self.rows)
+
+
+class FakeSession:
+    def __init__(self, objects=None, query_rows=None) -> None:
+        self.objects = objects or {}
+        self.query_rows = query_rows or {}
+        self.added = []
+        self.commits = 0
+        self.refreshes = []
+
+    def get(self, model, item_id):
+        return self.objects.get((model, item_id))
+
+    def query(self, model):
+        return FakeQuery(self.query_rows.get(model, []))
+
+    def add(self, item) -> None:
+        self.added.append(item)
+        if getattr(item, "id", None) is not None:
+            self.objects[(item.__class__, item.id)] = item
+
+    def commit(self) -> None:
+        self.commits += 1
+
+    def refresh(self, item) -> None:
+        self.refreshes.append(item)
+
+
+def _dataset(dataset_id, project_id, name):
+    return Dataset(
+        id=dataset_id,
+        project_id=project_id,
+        name=name,
+        dataset_type="vector",
+        source="manual",
+        dataset_role="source",
+    )
+
+
+def _feature(dataset_id, source_feature_id, geometry):
+    return VectorFeature(
+        id=uuid4(),
+        dataset_id=dataset_id,
+        source_feature_id=source_feature_id,
+        geometry=from_shape(geometry, srid=4326),
+        properties_json={"source_feature_id": source_feature_id},
+    )
+
+
+def test_change_detection_compares_persisted_vector_features() -> None:
+    project_id = uuid4()
+    source_dataset_id = uuid4()
+    target_dataset_id = uuid4()
+    source_dataset = _dataset(source_dataset_id, project_id, "before.geojson")
+    target_dataset = _dataset(target_dataset_id, project_id, "after.geojson")
+    rows = [
+        _feature(source_dataset_id, "source-unchanged", box(0, 0, 1, 1)),
+        _feature(source_dataset_id, "source-removed", box(10, 10, 11, 11)),
+        _feature(target_dataset_id, "target-unchanged", box(0, 0, 1, 1)),
+        _feature(target_dataset_id, "target-added", box(20, 20, 21, 21)),
+    ]
+    db = FakeSession(
+        objects={(Dataset, source_dataset_id): source_dataset, (Dataset, target_dataset_id): target_dataset},
+        query_rows={VectorFeature: rows},
+    )
+
+    result = ChangeDetectionService.compare_vector_datasets(
+        db=db,
+        project_id=project_id,
+        source_dataset_id=source_dataset_id,
+        target_dataset_id=target_dataset_id,
+        iou_threshold=0.8,
+    )
+
+    change_types = [feature["properties"]["change_type"] for feature in result.geojson["features"]]
+    assert result.source_feature_count == 2
+    assert result.target_feature_count == 2
+    assert result.added_count == 1
+    assert result.removed_count == 1
+    assert result.unchanged_count == 1
+    assert sorted(change_types) == ["added", "removed", "unchanged"]
+    assert result.warnings == []
+
+
+def test_change_detection_endpoint_returns_canonical_envelope(monkeypatch) -> None:
+    project_id = uuid4()
+    source_dataset_id = uuid4()
+    target_dataset_id = uuid4()
+    source_dataset = _dataset(source_dataset_id, project_id, "before.geojson")
+    target_dataset = _dataset(target_dataset_id, project_id, "after.geojson")
+    db = FakeSession(objects={(Dataset, source_dataset_id): source_dataset, (Dataset, target_dataset_id): target_dataset})
+    summary = ChangeDetectionSummary(
+        source_dataset_id=source_dataset_id,
+        target_dataset_id=target_dataset_id,
+        source_feature_count=1,
+        target_feature_count=1,
+        added_count=0,
+        removed_count=0,
+        unchanged_count=1,
+        iou_threshold=0.8,
+        warnings=[],
+        generated_at=datetime.now(timezone.utc),
+        geojson={"type": "FeatureCollection", "features": []},
+    )
+
+    monkeypatch.setattr(
+        "app.api.routes.analysis.ChangeDetectionService.compare_vector_datasets",
+        lambda **_kwargs: summary,
+    )
+    app.dependency_overrides[get_db] = lambda: db
+    try:
+        response = TestClient(app).post(
+            "/api/v1/analysis/change-detection",
+            json={
+                "source_dataset_id": str(source_dataset_id),
+                "target_dataset_id": str(target_dataset_id),
+                "iou_threshold": 0.8,
+                "include_unchanged": True,
+            },
+        )
+    finally:
+        app.dependency_overrides.pop(get_db, None)
+
+    assert response.status_code == 200
+    payload = response.json()
+    assert set(payload) == {"data"}
+    assert payload["data"]["job_type"] == "analysis.change-detection"
+    assert payload["data"]["status"] == "success"
+    assert payload["data"]["result_json"]["unchanged_count"] == 1
+    assert any(isinstance(item, Job) for item in db.added)