using System;
using System.Linq;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Data.Sqlite;
using Microsoft.EntityFrameworkCore;

await using var connection = new SqliteConnection("Data Source=:memory:;Foreign Keys=True");
await connection.OpenAsync();
var options = new DbContextOptionsBuilder<LabDb>().UseSqlite(connection).Options;
await using (var db = new LabDb(options))
{
    await db.Database.EnsureCreatedAsync(); var item = new Item { Name = "rune" }; db.Items.Add(item);
    Check(db.Entry(item).State == EntityState.Added, "added"); Console.WriteLine(db.Entry(item).State);
    await db.SaveChangesAsync(); Check(item.Id > 0 && db.Entry(item).State == EntityState.Unchanged, "saved identity"); Console.WriteLine(db.Entry(item).State);
    item.Name = "revised"; db.ChangeTracker.DetectChanges(); Check(db.Entry(item).State == EntityState.Modified, "detected edit"); Console.WriteLine(db.Entry(item).State);
    await db.SaveChangesAsync(); db.ChangeTracker.Clear(); Check(db.Entry(item).State == EntityState.Detached, "detached"); Console.WriteLine(db.Entry(item).State);
}
await using (var verify = new LabDb(options)) Check((await verify.Items.SingleAsync()).Name == "revised", "persisted rename");

static void Check(bool condition, string name) { if (!condition) throw new InvalidOperationException("CHECK: " + name); }