Starting with GeneXus 17 upgrade 8, GXtest started using an external tests runner instead of the TestsRunner and TestReferences procedures within the Knowledge Base. The goal of this change is to reduce build time and remove objects from the KB that are not related to the application being developed.
This change entails the following considerations.
1) For .Net framework environments, the only way to execute tests is to have the Build Mode as MSBuild.
2) TestsRunner and TestReferences procedures can now be removed from KBs since they won't be used anymore (assuming you are already on GX17U8 or greater).
3) The UpdateTestRefs task is no longer required to run tests. GXtest.msbuild file was updated taking this into consideration. However, the only thing to do if you have a custom MSBuild file (you should) is to remove the task from the target that uses it. Similarly, BuildOne task over TestsRunner procedure is no longer required.
4) RunTestsList task was deleted permanently after being deprecated since GeneXus 17 upgrade 3.