pybamm-team#4120 improved error message (pybamm-team#4208)

* pybamm-team#4120 improved error message

* style: pre-commit fixes

* updated test

* Update tests/unit/test_parameters/test_parameter_values.py

Co-authored-by: Eric G. Kratz <kratman@users.noreply.github.com>

* Update pybamm/parameters/parameter_values.py

Co-authored-by: Robert Timms <43040151+rtimms@users.noreply.github.com>

* Update pybamm/parameters/parameter_values.py

Co-authored-by: Eric G. Kratz <kratman@users.noreply.github.com>

---------

Co-authored-by: Ubham16 <you@example.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Arjun Verma <arjunverma.oc@gmail.com>
Co-authored-by: Eric G. Kratz <kratman@users.noreply.github.com>
Co-authored-by: Robert Timms <43040151+rtimms@users.noreply.github.com>

pybamm/parameters/parameter_values.py

@@ -65,7 +65,10 @@ def __init__(self, values, chemistry=None):
                 values.pop("chemistry", None)
                 self.update(values, check_already_exists=False)
             else:
-                raise ValueError("Invalid Parameter Value")
+                valid_sets = "\n".join(pybamm.parameter_sets.keys())
+                raise ValueError(
+                    f"'{values}' is not a valid parameter set. Parameter set must be one of:\n{valid_sets}"
+                )
 
         # Initialise empty _processed_symbols dict (for caching)
         self._processed_symbols = {}

tests/unit/test_parameters/test_parameter_values.py

@@ -43,7 +43,7 @@ def test_init(self):
             pybamm.ParameterValues(None, chemistry="lithium-ion")
 
         # junk param values rejected
-        with self.assertRaisesRegex(ValueError, "Invalid Parameter Value"):
+        with self.assertRaisesRegex(ValueError, "'Junk' is not a valid parameter set."):
             pybamm.ParameterValues("Junk")
 
     def test_repr(self):