Complete temporal detection safety gate

backend/tests/test_sprint8_detection_foundation.py

@@ -105,6 +105,25 @@ def test_non_raster_dataset_request_is_rejected() -> None:
     assert getattr(exc_info.value, "code", None) == "INVALID_DATASET_TYPE"
 
 
+def test_historical_raster_marked_unsupported_is_rejected_before_run_creation() -> None:
+    db, project_id, dataset_id = _project_and_dataset()
+    source = db.get(Dataset, dataset_id)
+    source.source_name = "digitaal_vlaanderen_orthophoto"
+    source.source_metadata = {"product_key": "2020", "supports_detection": False}
+
+    with pytest.raises(Exception) as exc_info:
+        DetectionService.run_detection(
+            db=db,
+            project_id=project_id,
+            dataset_id=dataset_id,
+            model_id="yolo-placeholder",
+            confidence_threshold=0.5,
+        )
+
+    assert getattr(exc_info.value, "code", None) == "DETECTION_SOURCE_TEMPORALLY_UNSUPPORTED"
+    assert db.added == []
+
+
 def test_fixture_detector_persists_detections_only_with_explicit_fixture_mode() -> None:
     db, project_id, dataset_id = _project_and_dataset()