で実行vstest.console.exe
し--diag:diag.txt
て、出力を確認してください。私にとっては、私の作業ディレクトリからのテストアダプターのDLL読み込みエラーでした。
TpTrace Information: 0 : 14976, 1, 2020/03/10, 15:34:22.120, 57158093583, vstest.console.exe, AssemblyResolver.OnResolve: Microsoft.VisualStudio.TestPlatform.MSTest.TestAdapter: Failed to load assembly. Reason:System.IO.FileLoadException: Could not load file or assembly 'file:///C:\Directory\Microsoft.VisualStudio.TestPlatform.MSTest.TestAdapter.dll' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)
File name: 'file:///C:\Directory\Microsoft.VisualStudio.TestPlatform.MSTest.TestAdapter.dll' ---> System.NotSupportedException: An attempt was made to load an assembly from a network location which would have caused the assembly to be sandboxed in previous versions of the .NET Framework. This release of the .NET Framework does not enable CAS policy by default, so this load may be dangerous. If this load is not intended to sandbox the assembly, please enable the loadFromRemoteSources switch. See http://go.microsoft.com/fwlink/?LinkId=155569 for more information.
vstest.console.exe.configに<loadFromRemoteSources enabled="true"/>
アンダー<runtime>
を追加してこれを回避しました