How to create fake data or mock data in unit test case for method using provider for database cal

Hi , I am looking for solution to handle database dependency code of method in unit test case

Below is My Registration Controller Class-

public class RegistrationController : Controller
{
 public async Task<ActionResult> Register(RegisterViewModel model)
    {

        // Validate uniqueness of UserName requested
        var uniqueUserNameQuery = UserInfoProvider.GetUsers().WhereEquals("UserName", model.UserName);
        if (uniqueUserNameQuery.Count > 0)
        {
            ModelState.AddModelError("UserName", "UserName is not available!");
        }
     if (!ModelState.IsValid)
        {
            List<StateInfo> stateInfos = GetStateSelection();
            model.State = new SelectList(stateInfos, "StateName", "StateDisplayName");
            return View(model);
        }
}
}

when i call above method in test case it will throw exception at point where i am calling UserInfoProvider.GetUsers because dependency is not handled in test case

so how to create fake data for user provider and how to pass it in method