Microsoft has recently published the Visual Studio 2019 Preview Release Notes. This version should be the last containing the Coded UI and load testing test features. Microsoft explains the removal of software testing features in future version of Visual Studio by the adoption of open source tools like Selenium, Appium or Apache JMeter.
Here are the parts about testing of the Visual Studio 2019 Preview release notes:
OSS UI test tools such as Selenium and Appium have gained momentum and have a strong community backing. Because these frameworks have become industry standards, we deprecated Coded UI test for automated UI-driven functional testing. Visual Studio 2019 will be the final version of Visual Studio with Coded UI test features. We recommend using Selenium for testing web-applications and Appium with WinAppDriver for testing desktop and UWP apps.
Visual Studio 2019 will be the last version of Visual Studio with load test features. For customers requiring load testing tools, we recommend using alternate load testing tools such as Apache JMeter, Akamai CloudTest, Blazemeter.
In Visual Studio 2019, some test window APIs that were previously marked public but were never officially documented have been removed. They were marked deprecated in Visual Studio 2017 to give extension maintainers an early warning. To our knowledge, very few extensions have taken a dependency on these APIs. These APIs include IGroupByProvider, IGroupByProvider, KeyComparer, ISearchFilter, ISearchFilterToken, ISearchToken and SearchFilterTokenType. If this change affects your extension, please let us know by submitting an issue on Developer Community.
Read the complete Visual Studio 2019 release notes on https://docs.microsoft.com/en-us/visualstudio/releases/2019/release-notes-preview