Stephen Walther on ASP NET MVC TDD : Introduction to Rhino Mocks

It create fake/mock implementation of objects behavior at runtime. It is written by Ayende Rahien, the same guy that created nHibernate. My typical dev unit testing environment would be Visual Studio (C#) + nUnit + Rhino.Mocks. You can either use the nUnit command line tools to run the tests or several good tools that integrate into Visual Studio, such as ReSharper, TestRunner.Net or, my favorite, NCrunch.

I think the rigidity in some mocking frameworks is largely a very very good thing. ” I thought I’ll be able to do things using the mocking framework withought changing my design as much…” Often to as a point of design – you don’t want to call virtual methods from the constructor – this can cause 5 Reasons to Automate Invoice Processing problems . For Rhino.Mocks, in order to provide an alternate implementation, you use the .Do() method to provide a delegate. In Moq, the .Returns() method has an overload that lets you provide a delegate. Along with CreateMock and DynamicMock you may notice some other mock creation methods.

The unit test executes quickly without requiring you to perform any configuration. You could run hundreds of unit tests that look just like this one each time you make a code change without significantly slowing down the process of developing an application. For both frameworks, you can explicitly verify stubs, but if you want to do mass verification, you must create the expectations up front. CreateMultiMock and DynamicMultiMock allow us to create a mock but supporting multiple types. In other words let’s assume our implementation of ISession is expected to support another interface, IStatusUpdate and this will have the event we’re previously declare, i.e.

If you call the Get() method with a ProductId that has not been setup, then the value Null is returned. Why should you care about Mock Object Frameworks such as Rhino Mocks? If you want to practice Test-Driven Development, then there is no way to avoid using a Mock Object Framework. You need to use a Mock Object Framework to create effective unit tests. You can verify individual call patterns, or you can verify all of the expectations you created in a single pass.

These problems are not part of our test that must to be kept simple and focused on a single assertion. We are going to test that when we call the method MakePizza, at the end of this call the property ReadyForAnotherPizza is set to true, as expected. Imagine that you have created the abstract base class in Listing 5. After you download and unzip Rhino Mocks, you can use Rhino Mocks in a project by adding a reference to the Rhino.Mocks.dll assembly. There is also an XML file included with the download that provides Intellisense for Rhino Mocks within Visual Studio. When performing state-based verification, the final statement in your unit test is typically an assert statement that asserts that some condition is true.

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At this time, all these mock objects, when invoked will return null. Howeverthis is not important for the specific test we are writing, so there is no need to overload our test with more configurations than needed. PartialMock() – This method of creating a mock object can only be performed on classes. There are three important differences that you should notice between Playbooks for installing Prometheus and Grafana on Kubernetes HPE Express Containers the code in Listing 11 and the code in the previous samples. First, notice that the sub for the IProductRepository interface is not created by using the GenerateStub() method like in previous code samples. When setting up method return values, you must create an instance of the Rhino Mocks MockRepository class and call the MockRepository instance’s Stub() method.

You’ll see in my test fixture file in theCode Used In Examplessection that I have done just that. I’ve passed this article on the others who are starting with Rhino. I know how time consuming 7 Crucial Roles in a Successful Software Development Team writing a blog post can be, so a post of this quality amazes me. The problem with this approach to building a Logger component is that it is not compatible with Rhino Mocks.

• There is also an XML file included with the download that provides Intellisense for Rhino Mocks within Visual Studio.
• For both frameworks, you can explicitly verify stubs, but if you want to do mass verification, you must create the expectations up front.
• I wrote a small application to use as a didactical tool.
• For example, Listing 14 contains a unit test for a logger component.
• In the second case we are asking to the mock Oven “please, verify if someone set the property Temperature in the Oven at 300C”.

And then we can test that every time we prepare a pizza, something is really cooked in this Oven. In this scenario we say that we are testing a behaviour. In this article I’m also explaining the main differences between Mock Objects and Stub objects, often confused when discussing about tests.

This provides an easy way for people to skim the content quickly if they prefer reading to watching, and to give the reader/watcher code samples and links to additional information. In behavior verification is a further step in verification. In behavior verification, we also check whether the sequence of operations in the object was correct and in particular order. When you have a dependency that your system under test uses, you may want to ensure that it is called with a value in an expected state. The following example is looking up aFooand we’re going to ensure that we’re calling theFooRepositorywith the Foo’sNameproperty.

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For this reason, in RhinoMock, we use the notation Arg.Is.Anything, that means “the object I’m passing into the method CookPizza can be any object that implements the interface IRawPizza”. Pragmatically Having issues following this out of date framework’s tutorial when intrinsic lets say common sense business logic is in Major Fail mode. There is a special kind of Mock objects, which are called “StrictMock”, that could be very useful…but only in very few scenarios. In our PizzaMaker is very important that we cook the pizza before serving it to the customers.

Both frameworks provide ways to put advanced constraints on the arguments that trigger a mock. Below are examples — you’ll need to consult the framework documentation for the full list of available constraints. If you need to pass arguments to the constructor of the class you’re trying to mock, there are overloads to allow you to do that. The test uses an expect label because the test and the assertion are combined – we expect that when we call getForegroundColour, this will return Colour.Red. This test states that we expect getForegroundColour to return the same colour as the palette’s primary colour. These objects are simple objects that stand-in for dependent objects.

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Instead of using a .Return() with a simple value, you can provide a full implementation of the method using the .Do() method. This also allows you to get access to the input parameters. If you want, you can define a delegate and just call the delegate.

The class is named PizzaMaker and offers a single method MakePizza() which will be tested. The code used as an example should be very easy to understand. I wrote a small application to use as a didactical tool. Use a stub when you want to supply a dependency that behaves a certain way. Use a Mock when you want to verify that a certain dependency has been interacted with correctly.

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When mocking a class, only virtual methods can be mocked. In Listing 12, two different products are returned when calling the Get() method depending on the value of the ProductId. In the Record() section of the test, the two different return values for the Get() method are setup. The test in Listing 9 creates a concrete instance of a class that implements the IProduct interface and passes the instance to the DoublePrice() method.

This type of testing is also called interaction-based testing. If you have created a mock that sets up expectations using .Expect() in Rhino.Mocks or .Verifiable() in Moq, you can use Moq’s .Verify() method to validate just those expectations. Moq also provides a .VerifyAll() method which will validate all of the mocks and stubs you’ve created with .Setup(). In Rhino.Mocks, you used the .Stub() and .Expect() extension methods to generate your stubs and mocks directly off your mock object. Moq, on the other hand, uses the .Setup() method on the wrapper object to create both. By default, it will create a stub , but if you add Verifiable(), it will generate the expectations .

One big difference between Rhino.Mocks and Moq is what gets returned when you generate the mock and how you operate against it. Moq, on the other hand, creates a wrapper object that contains a reference to the mocked type. What we’ve done is supply defaults which is what the dynamic mock object would have probably implemented for our expectations as well. Hence why I used Repeat.Any() to begin with, so the implementation above will now cause the test to succeed. Public void TearDown()
repository.VerifyAll();
this will verify that all mock expectations have been met when the test fixture is torn down.