In this page of JetBrains Rider options, you can adjust unit testing settings related to MSTest tests.
|Enable MSTest support||By default, JetBrains Rider adds action indicators allowing you to execute MSTest tests right from the editor and automatically discovers MSTest tests in your solution. Clear this check box to disable this behavior.|
|Choose the IDE folder|| As MSTest V1 is not distributed without Visual Studio, you have to specify the |
If you are using MSTest V2, which is delivered as a NuGet package, you do not need to specify the IDE folder.