Testing controls
From DotVVM 4.0, there is a new NuGet package called DotVVM.Testing which helps control developers to write unit test for DotVVM controls.
Please note that this package helps only to make sure the server-side part of the control works and that the control renders a correct HTML code. For proper end-to-end testing of DotVVM controls, you will need to use the control in an actual application and use tools like Selenium to interact with the control.
Helper classes
The DotvvmTestHelper class has static methods CreateConfiguration and CreateContext to create mocked DotvvmConfiguration and IDotvvmRequestContext for the purpose of testing.
The ControlTestHelper class is useful for testing custom controls. There is a RunPage(typeof(MyViewModel), "your dothtml code") which executes the DotVVM page and returns the HTML output parsed using the AngleSharp library.
See the CompositeControlTests.cs class in the DotVVM framework codebase - it shows how the control tests look like.
BindingTestHelper is useful for testing custom method translations - there are methods to create various bindings and compile them to JS.