PwParser: Fix case when settings are not provided

The `is_ionically_converged` check in the `PwParser` considers the
`FIXED_COORDS` setting when making sure the structure is ionically converged,
but did not consider the case when the `settings` are not provided as an input.
This would cause the parsing to fail in this case.

Here we use the typical approach to set the `settings` variable to an empty
dictionary in case the `settings` input is not provided.

The tests are also updated to not set the `settings` input by default in the
`generate_inputs` fixture for the `pw.x` parser tests.

Co-authored-by: Aliaksandr Yakutovich <yakutovicha@gmail.com>
Co-authored-by: Marnik Bercx <mbercx@gmail.com>

src/aiida_quantumespresso/parsers/pw.py

@@ -274,6 +274,8 @@ def is_ionically_converged(self, trajectory, except_final_scf=False):
 
         if 'settings' in self.node.inputs:
             settings = _uppercase_dict(self.node.inputs.settings.get_dict(), dict_name='settings')
+        else:
+            settings = {}
 
         fixed_coords = settings.get('FIXED_COORDS', None)
 

tests/parsers/test_pw.py

@@ -19,13 +19,16 @@ def _generate_inputs(calculation_type='scf', parameters=None, settings=None, met
         kpoints.set_cell_from_structure(structure)
         kpoints.set_kpoints_mesh_from_density(0.15)
 
-        return AttributeDict({
+        inputs = {
             'structure': generate_structure(),
             'kpoints': kpoints,
             'parameters': orm.Dict(parameters),
-            'settings': orm.Dict(settings),
             'metadata': metadata or {}
-        })
+        }
+        if settings:
+            inputs['settings'] = orm.Dict(settings)
+
+        return AttributeDict(inputs)
 
     return _generate_inputs