Add unrelated test to increase test coverage and unblock PR

Author: jnak

Diff for: graphene_sqlalchemy/tests/test_types.py

@@ -224,6 +224,19 @@ class Meta:
     assert pets_field.type().description == 'Overridden'
 
 
+def test_invalid_model_attr():
+    err_msg = (
+        "Cannot map ORMField to a model attribute.\n"
+        "Field: 'ReporterType.first_name'"
+    )
+    with pytest.raises(ValueError, match=err_msg):
+        class ReporterType(SQLAlchemyObjectType):
+            class Meta:
+                model = Reporter
+
+            first_name = ORMField(model_attr='does_not_exist')
+
+
 def test_only_fields():
     class ReporterType(SQLAlchemyObjectType):
         class Meta:

Diff for: graphene_sqlalchemy/types.py

@@ -133,7 +133,10 @@ def construct_fields(
     for orm_field_name, orm_field in custom_orm_fields_items:
         attr_name = orm_field.kwargs.get('model_attr', orm_field_name)
         if attr_name not in all_model_attrs:
-            raise Exception('Cannot map ORMField "{}" to SQLAlchemy model property'.format(orm_field_name))
+            raise ValueError((
+                "Cannot map ORMField to a model attribute.\n"
+                "Field: '{}.{}'"
+            ).format(obj_type.__name__, orm_field_name,))
         orm_field.kwargs['model_attr'] = attr_name
 
     # Merge automatic fields with custom ORM fields