test cases can't show in Test explorer of VS2017

[xuzhg]

I am using VS2017 Enterprise as below:

I can use VS2017 to open the Configuration.sln and it can load all test cases in the Test Explorer several days ago, But today it can't load test cases except for AzureKeyVault project as below as below:

do I miss something?

Thanks.

[shirhatti]

This issue was moved to dotnet/aspnetcore#2016