How to change property behavior for a mocked object
I'm trying to use the mocking framework for unit tests I'm trying to make the property of a mock object return another mock object, but the behavior object doesn't have the property classdef MyClass properties (GetAccess=public, SetAccess=protected) prop1; end methods function this = answer() end end end this is the mock decleration: testCase = matlab.mock.TestCase.forInteractiveUse; [mock,behav] = testCase.createMock(?MyClass); % this would obciously throw an exception because the property set method is protected mock.prop1 = ""; You cannot set the read-only property 'prop1' of MyClassMock. % this throws an exception because the behavior object doesn't have this property p = behav.prop1; No appropriate method, property, or field 'prop1' for class 'matlab.mock.classes.MyClassBehavior'. now i can't set the value of the mock object because the set access is protected and i can't use the behavior object to change the property behavior because I can't find the propertyBehavior thing anywhere I'm obviously missing something, but all the examples I've seen in the documentation show how to use a custom mock object with "AddedProperties" and I could be tackling this the wrong way, but I prefer to create the mock object using the meta class
John Michell answered .
2025-11-20
testCase = matlab.mock.TestCase.forInteractiveUse; [MyClassMock, behaviour] = createMock(testCase, 'AddedProperties', "prop1", 'AddedMethods', "answer") testCase.assignOutputsWhen(get(behaviour.prop1), 'abc') p = MyClassMock.prop1
It's not ideal but I don't think there's any other option at this time. You can still test for access violations this way:
import matlab.mock.actions.ThrowException
when(set(behaviour.prop1),...
ThrowException(MException('MATLAB:class:SetProhibited',...
'You cannot set the read-only property ''prop1'' of MyClass.')))
Creating a mock from a meta-class only works for classes with abstract properties and methods.