simple possiblity for overriding properties

When a class attribute is assigned with the same name as a property
from an inherited class, the property default is overridden.
If the type does not match, a ProgrammingError is raised.

Change-Id: Ifdab5c8bbdaae008370a9b297c770f5c04db9311
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/21989
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de>

test/test_properties.py

@@ -114,6 +114,36 @@ def test_Property_checks():
     o.checkProperties()
     o = cl()
     o.checkProperties()
+    # test for min/max check
     o.setProperty('maxabc', 1)
     with pytest.raises(ConfigError):
         o.checkProperties()
+
+def test_Property_override():
+    o1 = c()
+    class co(c):
+        a = 3
+    o2 = co()
+    assert o1.a == 1
+    assert o2.a == 3
+
+    with pytest.raises(ProgrammingError) as e:
+        class cx(c): # pylint: disable=unused-variable
+            def a(self):
+                pass
+    assert 'collides with method' in str(e.value)
+
+    with pytest.raises(ProgrammingError) as e:
+        class cy(c): # pylint: disable=unused-variable
+            properties = {
+                'b' : Property('', FloatRange(), 3.14),
+            }
+            b = 1.5
+
+    assert 'name collision with property' in str(e.value)
+
+    with pytest.raises(ProgrammingError) as e:
+        class cz(c): # pylint: disable=unused-variable
+            a = 's'
+
+    assert 'can not be set to' in str(e.value)