EF Core: semplice test unitario del modello di repository

Vorrei poter testare l'unità nel repository di informazioni ZIPCode con test di unità molto semplici. Mi chiedo come posso farlo? Potrei semplicemente iniettare un DbContext che utilizza un database fittizio (ad esempio RouteMiningTestDB).

Tuttavia, c'è un modo per farlo in memoria? Sto usando EF Core e voglio incapsularlo il più possibile. Inoltre, dovrei iniettare DbContext o una stringa di connessione? Ho visto entrambi usati e non riesco davvero a vedere gli svantaggi di entrambi. Grazie!

RouteMiningBLL.IZIPCodeInfoRepository

namespace RouteMiningBLL
{
    public interface IZIPCodeInfoRepository
    {
        void AddZIPCodeInfo(ZIPCodeInfo zipCodeInfo);
        ZIPCodeInfo GetByZIPCode(int zipcode);
        void UpdateZIPCodeInfo(ZIPCodeInfo zipCodeInfo);
        void DeleteZIPCodeInfo(int zipcode);
    }
}

RouteMiningDAL.ZIPCodeInfoRepository

using HtmlAgilityPack;
using Microsoft.EntityFrameworkCore;
using RouteMiningBLL;
using System.Linq;

namespace RouteMiningDAL
{
    public class ZIPCodeInfoRepository : IZIPCodeInfoRepository
    {
        // fix
        //private static string ConnectionString = @"Server=(localdb)\MSSQLLocalDB;Database=RouteMiningDB;Trusted_Connection=True;";
        //private RouteMiningDataContext db = new RouteMiningDataContext(new DbContextOptionsBuilder().UseSqlServer(ConnectionString).Options);

        private RouteMiningDataContext db;

        public ZIPCodeInfoRepository(RouteMiningDataContext dbContext)
        {
            db = dbContext;
        }

        public void AddZIPCodeInfo(RouteMiningBLL.ZIPCodeInfo zipCodeInfo)
        {
            db.ZIPCodeInfo.Add(MapBLLToDAL(zipCodeInfo));
            db.SaveChanges();
        }

        public RouteMiningBLL.ZIPCodeInfo GetByZIPCode(int zipcode)
        {
            var info = db.ZIPCodeInfo.Find(zipcode);
            var zipcodeinfo = new RouteMiningBLL.ZIPCodeInfo(info.ZIPCode, info.Population, info.AverageHomeValue, info.HouseHoldIncome, info.MedianAge, info.NumberOfBusinesses, info.NumberOfEmployees);

            return zipcodeinfo;
        }

        public void UpdateZIPCodeInfo(RouteMiningBLL.ZIPCodeInfo zipCodeInfo)
        {
            throw new System.NotImplementedException();
        }

        public void DeleteZIPCodeInfo(int zipcode)
        {
            ZIPCodeInfo info = db.ZIPCodeInfo.Find(zipcode);
            db.ZIPCodeInfo.Remove(info);
        }

        private ZIPCodeInfo MapBLLToDAL(RouteMiningBLL.ZIPCodeInfo zipCodeInfo)
        {
            var info = new ZIPCodeInfo
            {
                ZIPCode = zipCodeInfo.ZIPCode,
                Population = zipCodeInfo.Population,
                AverageHomeValue = zipCodeInfo.AverageHomeValue,
                HouseHoldIncome = zipCodeInfo.HouseHoldIncome,
                MedianAge = zipCodeInfo.MedianAge,
                NumberOfBusinesses = zipCodeInfo.NumberOfBusinesses,
                NumberOfEmployees = zipCodeInfo.NumberOfEmployees
            };

            return info;
        }
    }
}