Mocking is a concept in Unit Testing where the dependencies in the software being tested are substituted with proxies that are programmed to act in a controlled manner. This prevents those dependencies from interfering with the results. Mocking is commonly used for removing dependencies like database or file system access, or calls to code that are out of scope for the unit being tested.

For a deeper discussion on the benefits of mocking, please refer to this blog post by Telerik Evangelist Phil Japikse.

JustMock is a fast fully featured mocking framework for .NET that helps you create unit tests more quickly by automatically mocking or “faking,” objects in your tests. Mocking helps you break dependencies in your unit tests so that you can focus on testing a single concern and provide more complete unit test coverage. 

Mock objects can be created and maintained manually, but this is a time consuming and ultimately unproductive approach. A tool like JustMock allows you to focus on writing tests and forget about the mocking details. Mock objects are created automatically in memory when the tests run based on your simple configuration in the unit test. There are no “physical” mock objects that have to be maintained as your project changes.

JustMock goes even further and does not force you to distinguish between “mocks,” “fakes,” and “stubs.” With JustMock,you have a single, easy to use API for all of your mocking needs.

Among the many features in JustMock, here are areas where Telerik provides unique value:

• Performance – JustMock ships with both “simple” (aka, Proxy) and Profiler API-based (aka, Elevated) approaches for mocking so that you can use the technique best suited for your code. The simple method is comparable to many open source frameworks and is fast and easy to setup/deploy. The Profiler-based approach is what commercial mocking frameworks tend to employ, and it is more powerful, capable of mocking just about everything. Our hybrid approach is unique and gives you the best of both worlds.
• Simplicity – JustMock makes mocking simple with a strongly-typed, fluid API that employs the AAA Pattern- Arrange/Act/Assert. There is one simple way to use JustMock, based on the latest .NET framework features, so no “legacy” concepts pollute the API.
• Integration – JustMock is just one part of the Telerik developer toolbox. It integrates with tools like JustCode, which can provide a simple wizard for creating mocks, to make mocking even easier.
• Support- JustMock is backed by legendary Telerik support. By picking a mocking tool backed by support professionals ready to help you be productive you no longer need to waste time looking for answers to your questions.
• Flexibility – JustMock Lite edition is a solid mocking platform and an excellent introductory tool if you are new to mocking. And if you ever need more functionality in the future, the upgrade to the commercial edition takes no time at all, plus you can keep on working with the same codebase.

Of course. In addition to comprehensive documentation online, when you download JustMock, you’ll find a demo project that shows you, through code, all of the various ways you can use JustMock.

You can also visit the JustMock forums, which are frequented by Telerik developers who make sure that no question is left unanswered and no issue goes unaddressed.

The Arrange/Act/Assert pattern is a more logical and clean approach to unit testing than the legacy Record/Replay. With AAA, you group your testing actions by function, making it clear what part of your test is involved in setup versus verification. The pattern can be applied to all unit testing, but it is especially useful when mocking is involved.

Record/Replay is an older pattern and it is similar to using GOTO statements in your unit tests. This makes the pattern more difficult to follow and clearly less ideal from a programming perspective. Therefore, JustMock is focused on supporting the AAA pattern.

Yes, the JustMock profiler is compatible with Visual Studio Code Coverage, Visual Studio IntelliTrace, Visual Studio Profiler, NCrunch, NCover, OpenCover, dotCover, dotTrace Performance.

It is possible to overuse mocking. The goal of mocking is to isolate the code you want to test from other components in the system. There are two rules of thumb that should be followed to ensure mocking is done properly:

1. Only test (and thus mock) the external behavior of any object.
Mocking the internal behavior of objects can make unit tests brittle and hard to maintain during refactoring.
2. Mock all objects and external dependencies that are not being actively tested.
Mocking all objects obviously produces meaningless test results. Use mocking to keep unit tests focused on the behavior of the method you’re testing. Nothing more. Nothing less.

Yes, JustMock is available as a standalone license and as a license with subscription. Please follow this link for current pricing information.

JustMock comes in two editions. JustMock Lite, the free edition, mocks interfaces events, exceptions, properties and behaviors but cannot perform elevated mocking. JustMock, the full edition, performs elevated mocking enabling you to mock framework classes (such as msCorlib), LINQ queries to static methods and sealed classes. Upgrading from JustMock Lite to JustMock the full edition, is easy and you can even continue to work with the same codebase.

Both editions benefit from three major releases a year, plus service packs and hotfixes when needed. For a full comparison, please check the comparison table on the JustMock Lite page.

JustMock is not an open source product. It’s built from the ground up by Telerik and benefits from an aggressive release schedule. Unlike other free tools, the JustMock Lite edition includes its own dynamic proxy, thus allowing for greater flexibility in its use. In addition, the JustMock Lite edition is built on the same platform as the JustMock complete edition, enabling easy upgrade.