When mocking dependencies in my Angular tests, I usually create a spy object using jasmine.createSpyObj:

const serviceSpy= jasmine.createSpyObj('MyService', ['method']);

then provide it to the TestBed:

  providers: [

    {provide: MyService, useValue: serviceSpy}

  ]

When I use it in my test, I can then specify the desired return value:

serviceSpy.method.and.returnValue(of([...]));

Now I also need to mock properties and I cannot find out how it should be done. createSpyObj does allow the definition of property names:

const serviceSpy= jasmine.createSpyObj('MyService', ['method'], ['property']);

but I've tried varies solutions based on the numerous articles and answers out there without any success, e.g.:

// Cannot read property 'and' of undefined    

serviceSpy.property.and.returnValue(true);  

// not declared configurable

spyOnProperty(serviceSpy, 'property').and.returnValue(true);  

// no build errors, but value stays 'undefined'

serviceSpy.property = true;  

The only way I could make it 'half' work is:

let fakeValue = true;

const serviceSpy= jasmine.createSpyObj('MyService', ['method'], {'property': fakeValue});

The problem here is that it's a one-time set at creation. If I want to change the expected value in the test, it does not work.

fakeValue = false;

serviceSpy.property ==> stays to the initial value 'true';

Does there exist a solution to both mock methods and properties by creating a spy object, or should I create my own fake class on which I can then use spyOn and spyOnProperty?

I would also like to know what the usage is of the properties array in the createSpyObj definition. So far I have not seen any example on the web that explains it.