Tests are not executed in appveyor build

[HerbertBodner]

Build output says:

Discovering tests...OK
vstest.console /logger:Appveyor "C:\projects\webapp-core\src\WaCore.Crud.UnitTests\bin\Release\netcoreapp2.0\WaCore.Crud.UnitTests.dll"
Microsoft (R) Test Execution Command Line Tool Version 15.0.26720.2
Copyright (c) Microsoft Corporation.  All rights reserved.
Starting test execution, please wait...
Warning: No test is available in C:\projects\webapp-core\src\WaCore.Crud.UnitTests\bin\Release\netcoreapp2.0\WaCore.Crud.UnitTests.dll. Make sure that installed test discoverers & executors, platform & framework version settings are appropriate and try again.
Information: Additionally, you can try specifying '/UseVsixExtensions' command if the test discoverer & executor is installed on the machine as vsix extensions and your installation supports vsix extensions. Example: vstest.console.exe myTests.dll /UseVsixExtensions:true

using dotnet test should fix the issue: microsoft/azure-pipelines-tasks#5066

test results should be uploaded to appveyor as well: https://www.appveyor.com/docs/running-tests/#pushing-real-time-test-results-to-build-console