Despite the declared support for test codeunits in the Cloud, for some reason libraries are not available to us, and they, in turn, are convenient for writing tests.

Examle of test libraries, also we need Sales/Purchase libraries and so on:
https://github.com/microsoft/ALAppExtensions/tree/master/Modules/DevTools/TestFramework/TestLibraries

Moreover, the recommendations from Microsoft say that it is better to use them than to write your own every time.Unfortunately, we cannot install these libraries on cloud.
https://docs.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/devenv-testing-application
And the maximum that we can use OnPrem or Docker for this.

Let's add the ability to install standard test libraries in the Cloud BC.