test(parameter): add unit test for addition of new attributes to parameter classes

Author: amyheather

tests/test_unittest.py

@@ -0,0 +1,29 @@
+"""
+Unit tests
+"""
+
+import pytest
+
+from simulation.parameters import (
+    ASUArrivals, RehabArrivals, ASULOS, RehabLOS,
+    ASURouting, RehabRouting, Param)
+
+
+@pytest.mark.parametrize('class_to_test', [
+    ASUArrivals, RehabArrivals, ASULOS, RehabLOS,
+    ASURouting, RehabRouting, Param])
+def test_new_attribute(class_to_test):
+    """
+    Confirm that it's impossible to add new attributes to the classes.
+
+    Arguments:
+        class_to_test (class):
+            The class to be tested for attribute immutability.
+    """
+    # Create an instance of the class
+    instance = class_to_test()
+
+    # Attempt to add a new attribute
+    with pytest.raises(AttributeError,
+                       match='only possible to modify existing attributes'):
+        setattr(instance, 'new_entry', 3)