Using IHostingEnvironment in .NetCore library

Question

I build an ASP.NET Core application and I create a .NET Core Class Library for unit testing.

I want to use IHostingEnvironment in my library (to get physical path of a file), so I've added this line to Startup.cs of my ASP.NET Core application :

services.AddSingleton<IHostingEnvironment>();

In the Library I've added reference to my ASP.NET application, and in my class I wrote this:

private IHostingEnvironment _env;
public Class1(IHostingEnvironment env)
{
    _env = env;
}

But when I run it then it gives me this error:

the following constructor parameters did not have matching fixture date : IHostingEnvironment env

What is the problem? How can I use it in .NET Core Class Library?

---

EDIT: I tried to use this too:

IServiceCollection services = new ServiceCollection();
services.AddSingleton<IHostingEnvironment>();
IServiceProvider provider = services.BuildServiceProvider();
IHostingEnvironment service = provider.GetService<IHostingEnvironment>();
var p = service.WebRootPath; 

The last one gives me this error:

Cannot instantiate implementation type 'Microsoft.AspNetCore.Hosting.IHostingEnvironment' for service type 'Microsoft.AspNetCore.Hosting.IHostingEnvironment'

Answer 1

This worked for me in both .net core class library and console application:

Using references,

using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Hosting.Internal;

Adding DI registration,

services.AddSingleton<IHostingEnvironment, HostingEnvironment>();