negative cases for dem download

tests/test_dem.py

@@ -1,3 +1,5 @@
+import pytest
+
 from pathlib import Path
 from unittest import mock
 
@@ -19,3 +21,26 @@ def test_download_dem_for_srg(monkeypatch):
             [str(Path.cwd() / 'elevation.dem'), str(Path.cwd() / 'elevation.dem.rsc'), 3, 1, 0, 2],
             work_dir=Path.cwd(),
         )
+
+
+def test_download_dem_from_bounds(monkeypatch):
+    with monkeypatch.context() as m:
+        mock_ensure_egm_model_available = mock.Mock()
+        m.setattr(dem, 'ensure_egm_model_available', mock_ensure_egm_model_available)
+        mock_call_stanford_module = mock.Mock()
+        m.setattr(utils, 'call_stanford_module', mock_call_stanford_module)
+        dem.download_dem_from_bounds([1.0, 0.0, -1.0, 1.0], Path.cwd())
+        mock_ensure_egm_model_available.assert_called_once()
+        mock_call_stanford_module.assert_called_once_with(
+            'DEM/createDEMcop.py',
+            [str(Path.cwd() / 'elevation.dem'), str(Path.cwd() / 'elevation.dem.rsc'), 1.0, 0.0, -1.0, 1.0],
+            work_dir=Path.cwd(),
+        )
+        bad_bboxs = [
+            [0.0, 1.0, -1.0, 1.0],
+            [1.0, 1.0, -1.0, 1.0],
+            [1.0, 0.0, 1.0, -1.0]
+        ]
+        for bbox in bad_bboxs:
+            with pytest.raises(ValueError, match=r'Improper bounding box formatting*'):
+                dem.download_dem_from_bounds(bbox, Path.cwd())