Support for mutable and immutable configurations

tests/test_configuration_class.py

@@ -12,7 +12,7 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 
-from src.config_parser import Configuration
+from src.config_parser import Configuration, set_mutability, is_mutable
 
 def test_crud_configuration_attrs():
     config = Configuration()
@@ -76,4 +76,37 @@ def test_crud_configuration_config_items():
         config.key1
         assert False, "AttributeError was not raised"
     except AttributeError:
-        pass
+        pass
+
+def test_mutability():
+    config = Configuration(mutable=False)
+    try:
+        config.key = 'value'
+        assert False, 'Expected TypeError'
+    except TypeError:
+        pass
+
+    set_mutability(config, True)
+    assert config._mutable == True
+
+    config.key = 'value'
+
+    set_mutability(config, False)
+    assert config._mutable == False
+    assert is_mutable(config) == False
+
+    try:
+        del config.key
+        assert False, 'Expected TypeError'
+    except TypeError:
+        pass
+
+
+    # Test operate_on_original_object parameter of set_mutability
+    config = Configuration(mutable = True)
+    set_mutability(config, False, operate_on_original_object = True)
+    assert is_mutable(config) == False
+
+    new_config = set_mutability(config, True, operate_on_original_object = False)
+    assert is_mutable(new_config) == True
+    assert is_mutable(config) == False