raise error when select on bad patch coord

d-chambers · d-chambers · commit c5c32c3cafc7 · 2025-09-26T17:06:34.000+01:00
diff --git a/dascore/proc/coords.py b/dascore/proc/coords.py
@@ -10,7 +10,12 @@
 
 from dascore.constants import PatchType, select_values_description
 from dascore.core.coords import BaseCoord
-from dascore.exceptions import CoordError, ParameterError, PatchError
+from dascore.exceptions import (
+    CoordError,
+    ParameterError,
+    PatchCoordinateError,
+    PatchError,
+)
 from dascore.utils.docs import compose_docstring
 from dascore.utils.misc import get_parent_code_name, iterate
 from dascore.utils.patch import patch_function
@@ -497,6 +502,15 @@ def select(
       See [`Patch.order`](`dascore.Patch.order`).
 
     """
+    # Check for and raise on invalid kwargs.
+    if invalid_coords := set(kwargs) - set(patch.coords.coord_map):
+        invalid_list = sorted(invalid_coords)
+        valid_list = sorted(patch.coords.coord_map)
+        msg = (
+            f"Coordinate(s) {invalid_list} not found in patch coordinates: {valid_list}"
+        )
+        raise PatchCoordinateError(msg)
+
     new_coords, data = patch.coords.select(
         **kwargs,
         array=patch.data,
diff --git a/tests/test_proc/test_proc_coords.py b/tests/test_proc/test_proc_coords.py
@@ -14,6 +14,7 @@
     CoordError,
     ParameterError,
     PatchBroadcastError,
+    PatchCoordinateError,
     PatchError,
 )
 from dascore.units import get_quantity
@@ -321,6 +322,33 @@ def test_patch_non_coord(self, random_patch):
         new = patch.select(face_angle=(face_angle.min(), face_angle.max()))
         assert new == patch
 
+    def test_select_nonexistent_coordinate_raises_error(self, random_patch):
+        """
+        Test that selecting on a non-existing coordinate
+        raises PatchCoordinateError.
+        """
+        # Try to select on a coordinate that doesn't exist
+        with pytest.raises(PatchCoordinateError, match="nonexistent_coord"):
+            random_patch.select(nonexistent_coord=(0, 10))
+
+    def test_select_multiple_nonexistent_coordinates_raises_error(self, random_patch):
+        """
+        Test that selecting on multiple non-existing coordinates raises
+        PatchCoordinateError.
+        """
+        # Try to select on multiple coordinates that don't exist
+        with pytest.raises(PatchCoordinateError, match="coord1.*coord2"):
+            random_patch.select(bad_coord1=(0, 10), bad_coord2=(5, 15))
+
+    def test_select_mix_valid_invalid_coordinates_raises_error(self, random_patch):
+        """
+        Test that mixing valid and invalid coordinates raises
+        PatchCoordinateError.
+        """
+        # Try to select on a mix of valid and invalid coordinates
+        with pytest.raises(PatchCoordinateError, match="invalid_coord"):
+            random_patch.select(time=(0, 1), invalid_coord=(0, 10))
+
 
 class TestOrder:
     """Tests for ordering Patches."""
