Unit test AuthorizationHandler

Question

I used the resource-based authorization pattern in .NET Core 2.1 as described here. The only problem that I have is I have no idea how to test my AuthorizationHandler cleanly.

Anyone here done something like that already?

AuthorizationHandler sample (from the above link):

public class DocumentAuthorizationHandler : 
    AuthorizationHandler<SameAuthorRequirement, Document>
{
    protected override Task HandleRequirementAsync(AuthorizationHandlerContext context,
                                                   SameAuthorRequirement requirement,
                                                   Document resource)
    {
        if (context.User.Identity?.Name == resource.Author)
        {
            context.Succeed(requirement);
        }

        return Task.CompletedTask;
    }
}

public class SameAuthorRequirement : IAuthorizationRequirement { }