Partially prevent ase_calculator from failing silently.

src/atomate2/forcefields/utils.py

@@ -42,8 +42,15 @@ def ase_calculator(calculator_meta: str | dict, **kwargs: Any) -> Calculator | N
     """
     calculator = None
 
-    if isinstance(calculator_meta, str) and calculator_meta in map(str, MLFF):
-        calculator_name = MLFF(calculator_meta.split("MLFF.")[-1])
+    if isinstance(calculator_meta, str):
+        valid_calculators = [name.split("MLFF.")[-1] for name in map(str, MLFF)]
+
+        if "MLFF." in calculator_meta:
+            calculator_name = MLFF(calculator_meta.split("MLFF.")[-1])
+        elif calculator_meta in valid_calculators:
+            calculator_name = MLFF(calculator_meta)
+        else:
+            raise ValueError(f"Could not create calculator from {calculator_meta}.")
 
         if calculator_name == MLFF.CHGNet:
             from chgnet.model.dynamics import CHGNetCalculator

tests/forcefields/test_utils.py

@@ -17,6 +17,18 @@ def test_ext_load(force_field: str):
     assert calc_from_decode.parameters == calc_from_preset.parameters == {}
 
 
+def test_raises_error():
+    with pytest.raises(ValueError, match="Could not create"):
+        ase_calculator("not_a_calculator")
+
+
+@pytest.mark.parametrize(("force_field"), ["CHGNet", "MACE"])
+def test_accepts_stubs(force_field: str):
+    calculator1 = ase_calculator("MACE")
+    calculator2 = ase_calculator(str(MLFF.MACE))
+    assert calculator1.name == calculator2.name
+
+
 def test_m3gnet_pot():
     import matgl
     from matgl.ext.ase import PESCalculator