[assembly: InternalsVisibleTo("TestProject")]
注意，如果要去掉AssemblyKeyFile和AssemblyKeyName，即使这两个是空也不行，不然会报这个错误。
Error 1 Friend assembly reference 'TestProject' is invalid. Strong-name signed assemblies must specify a public key in their InternalsVisibleTo declarations.
去掉下面两行就好了。
//[assembly: AssemblyKeyFile("")]
//[assembly: AssemblyKeyName("")]