R – How to test a writeonly property

rhino-mocks

In my application, using MVP pattern, presenter is setting some properties on view.For example, Iview has string Customer {set;}.Now, I want to test that this property was set with some value "x".How can I do the test with rhino mocks?

Best Answer

Don't define write-only properties. As the .NET design guidelines say:

Do not provide set-only properties.

If the property getter cannot be provided, use a method to implement the functionality instead. The method name should begin with Set followed by what would have been the property name. For example, AppDomain has a method called SetCachePath instead of having a set-only property called CachePath.

In most cases, defining a read/write property is much easier, and it makes it a breeze to unit testi the owning type. You wouldn't need Rhino Mocks for that, as you can simply read the value directly from the property.

However, if you rather want a mutating method as described in the design guidelines, you must make it virtual to be able to use Rhino Mocks to verify that it was correctly called. Although this is certainly possible, it's more complicated to set up, so I would only take that route if there were compelling reasons to do so.

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What are the differences between mocks and stubs on Rhino Mocks

As per this

... Put simply there is a difference between Mock and Stub objects and RhinoMocks recognizes that allowing us to write tests that better state their purpose.

Mock objects are used to define expectations i.e: In this scenario I expect method A() to be called with such and such parameters. Mocks record and verify such expectations.

Stubs, on the other hand have a different purpose: they do not record or verify expectations, but rather allow us to “replace” the behavior, state of the “fake”object in order to utilize a test scenario ...

R – Using Rhino Mocks, why does invoking a mocked on a property during test initialization return Expected call #1, Actual call #0

Why in the world would you want to test the same thing each time a test is run?

If you want to test that a specific thing happens, you should check that in a single test.

The pattern you are using now implies that you need to - set up prerequisites for testing - do behavior - check that behavior is correct and then repeat that several times in one test

You need to start testing one thing for each test, and that help make the tests clearer, and make it easier to use the AAA syntax.

There's several things to discuss here, but it certainly would be clearer if you did it something like:

[TestMethod]
ShouldCallInvokedMethodWhenSettingProperty()
{
   var viewMock = MockRepository.GenerateMock<IView>()

   var presenter = new Presenter(viewMock);

   presenter.Property = 1;

   viewMock.AssertWasCalled(view => view.InvokedMethod());

}

Read up more on Rhino Mocks 3.5 syntax here: http://ayende.com/Wiki/Rhino+Mocks+3.5.ashx

Best Answer

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What are the differences between mocks and stubs on Rhino Mocks

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