I want to use the `IHostingEnvironment` and `ConfigurationBuilder` in my functional test project, so that depending on the environment the functional tests run using a different set of configuration. I want to make use of the code below:

```
public IConfigurationRoot ConfigureConfiguration(IHostingEnvironment hostingEnvironment)
{
    var builder = new ConfigurationBuilder()
        .AddJsonFile("appsettings.json")
        .AddJsonFile($"appsettings.{hostingEnvironment.EnvironmentName}.json", true)
        .AddEnvironmentVariables();
    return builder.Build();
}

```

I want to have an `appSettings.json` and `appSettings.Production.json` file to point my functional tests at production. Is this possible? How can it be achieved? I would need an instance of `IHostingEnvironment`.