.NET Standard 没有运行时，因此它不会执行您的测试.

There is no runtime for .NET Standard, so it will not execute your tests.

您的测试程序集必须面向可执行平台，例如 .NET Framework 或 .NET Core 的某个版本.

Your test assembly must target an executable platform, such as a version of .NET Framework or .NET Core.

<TargetFramework>net470</TargetFramework>

或

<TargetFramework>netcoreapp2.0</TargetFramework>

有关详细信息，请参阅在不同框架上运行 .NET Standard 二进制文件.

See Running .NET Standard binaries on different frameworks for more details.