GEOPY-2421: Add custom error for topography grid selected without data

simpeg_drivers/options.py

@@ -17,7 +17,6 @@
 
 import numpy as np
 from geoapps_utils.base import Options
-from geoapps_utils.utils.importing import GeoAppsError
 from geoh5py.data import (
     BooleanData,
     DataAssociationEnum,
@@ -92,6 +91,16 @@ def at_least_one(cls, data):
             raise ValueError("Must provide either topography or active model.")
         return data
 
+    @model_validator(mode="before")
+    @classmethod
+    def topo_grid_must_have_elevation_channel(cls, data):
+        if isinstance(data.get("topography_object", None), Grid2D):
+            if data.get("topography", None) is None:
+                raise ValueError(
+                    "Grid2D topography must be accompanied by a valid elevation channel."
+                )
+        return data
+
     @model_serializer(mode="wrap")
     def serialize_model(self, handler) -> dict[str, Any]:
         result = handler(self)

tests/validations_test.py

@@ -11,6 +11,7 @@
 import pytest
 from geoapps_utils.utils.importing import GeoAppsError
 from geoh5py import Workspace
+from geoh5py.objects import Grid2D
 
 from simpeg_drivers.options import CoreOptions
 
@@ -23,3 +24,25 @@ def test_topo_or_active_validation(tmp_path):
         }
     with pytest.raises(GeoAppsError, match="active_cells: Value error, Must"):
         CoreOptions.build(data)
+
+
+def test_topo_grid_missing_elevation(tmp_path):
+    with Workspace(tmp_path / "test.geoh5") as workspace:
+        grid = Grid2D.create(
+            workspace,
+            name="grid",
+            u_cell_size=10,
+            v_cell_size=10,
+            u_count=10,
+            v_count=10,
+            origin=[0, 0, 0],
+        )
+
+        data = {
+            "geoh5": workspace,
+            "inversion_type": "mvi",
+            "topography_object": grid,
+            "topography": None,
+        }
+    with pytest.raises(GeoAppsError, match="active_cells: Value error, Grid2D"):
+        CoreOptions.build(data)