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(); db.Items.Add(new Item { Name = "rune" }); await db.SaveChangesAsync(); db.ChangeTracker.Clear();
    var detached = await db.Items.AsNoTracking().SingleAsync(); Check(!db.ChangeTracker.Entries().Any(), "untracked result"); detached.Name = "draft";
    Check(await db.SaveChangesAsync() == 0, "no pending tracked update");
}
await using (var verify = new LabDb(options))
{
    Check((await verify.Items.AsNoTracking().SingleAsync()).Name == "rune", "untracked edit not saved"); Console.WriteLine("stored:rune");
    var tracked = await verify.Items.SingleAsync(); tracked.Name = "saved"; await verify.SaveChangesAsync();
}
await using (var verify = new LabDb(options)) { Check((await verify.Items.SingleAsync()).Name == "saved", "tracked edit saved"); Console.WriteLine("stored:saved"); }

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