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Telerik Ninja for R1 2021 Release

It’s time for the R1 release of Telerik JustMock for 2021, and it offers performance improvements, the official release of the DebugWindow with a new user experience and support for all features available in C# 8 and 9.

Official Release of Debug Window Coming with New User Experience

Due to popular demand, with R2 2020 we introduced the Debug Window feature as a beta. Thanks to your valuable feedback and our team's hard work since then, we managed to fix all known issues and added more functionality. With R1 2021, we are officially releasing it with an updated user experience. Let us know what you think about it in the comments or through the feedback portal and the support system.

Performance Optimization when Executing Tests with the Profiler Enabled

The profiler behind JustMock is the main force that unleashes the power of JustMock and allows it to mock almost everything of what is available in C# or VB. Those of you who are familiar with how a profiler works will know that few lines of code are inserted (instrumented) into each method that is compiled by the CLR. This instrumentation is the core of that power, but it comes at a price and the price is performance. We know that JustMock can be slow when you have tens of thousands of tests.

To improve the performance, we have implemented a configuration in JSON format which you can use to filter what should be instrumented and what not. In the following example I will show how by default everything will be excluded from what should be available for mocking and allow just mscorlib and the library for which I will write the tests to be included. Here is the example:

  "weavingFilter": {
    "defaultAction": "exclude",
    "entries": [
        "scope": "module",
        "pattern": "mscorlib",
        "action": "include"
        "scope": "module",
        "pattern": "App.Sample",
        "action": "include"

For more information check the documentation article.

JustMock Claims Support for C# 8 & C# 9

The pace with which .NET started to develop has increased during the last years, and with that the demands on developers to migrate to the latest versions. We firmly believe that the tooling that you use in your daily job activities should not be a stopper for you to take advantage of all the improvements available with those latest versions. This is why made a deliberate effort to test if JustMock can handle all the new C# 8 and C# 9 features which makes sense to be used alongside a mock, and we can say that no issues were found. With that, JustMock now claims support for C# 8 and 9 features.


.NET 5 Support

Many of you are following only the official release blog posts and are skipping all service packs releases. Because of this I wanted to mention that since the last service pack, R3 2020 SP2, JustMock supports .NET 5. If you have missed it, you can check it here: link

Net 5 and JustMock

The R1 2021 release is already available for download in customers’ accounts. If you are new to Telerik JustMock, you can learn more about it via the product page. It comes with a 30-day free trial, giving you some time to explore the capabilities of JustMock.

Try JustMock Now

Sign Up for the Webinar and Catch Us on Twitch

To see the new release in action, please join us on the Telerik R1 2021 webinar, on Tuesday, January 26, 2021 11:00 AM ET - 1 PM ET. You can also catch our full-day live session on Twitch on January 29th from 8am - 5pm ET where our developer advocates will dive into all your favorite features.

Save My Webinar Seat

Feel free to drop us a comment below sharing your thoughts. Or visit our Feedback Portal and let us know if you have any suggestions or if you need any particular features.

You can also check our Release History page for a complete list of the included improvements.

Mihail Vladov
About the Author

Mihail Vladov

Mihail Vladov is a Software Engineering Manager at Progress. He has more than a decade of experience with software and product development and is passionate about good software design and quality code. Mihail helped develop the WPF controls suite and Document Processing libraries which are used by thousands of developers. Currently, he is leading the JustMock team. In his free time, he loves to travel and taste different foods. You can find Mihail on LinkedIn.

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