ef core unit test echec - unit-testing

Question

I have a method in my repository that I’m trying to test
public User UpdateUserManyToMany(User user, List<Guid> manyToManyds)
{
var dbContext = _databaseContext as DbContext;
dbContext?.TryUpdateManyToMany(user.ManyToMany, manyToManyds
.Select(x => new ManyToMany{
OtherEntityId = x,
UserId = user.Id,
}), x => x.OtherEntityId);
return user;
}
My ManyToMany Entity :
public class ManyToMany
{
public Guid OtherEntityId { get; set; }
public OtherEntity OtherEntityId { get; set; }
public Guid UserId { get; set; }
public User User { get; set; }
}
My TryUpdateManyToMany :
public static class ManyToManyExtensions
{
public static void TryUpdateManyToMany<T, TKey>(this DbContext db, IEnumerable<T> currentItems, IEnumerable<T> newItems, Func<T, TKey> getKey) where T : class
{
db.Set<T>().RemoveRange(currentItems.Except(newItems, getKey));
db.Set<T>().AddRange(newItems.Except(currentItems, getKey));
}
public static IEnumerable<T> Except<T, TKey>(this IEnumerable<T> items, IEnumerable<T> other, Func<T, TKey> getKeyFunc)
{
return items
.GroupJoin(other, getKeyFunc, getKeyFunc, (item, tempItems) => new { item, tempItems })
.SelectMany(t => t.tempItems.DefaultIfEmpty(), (t, temp) => new { t, temp })
.Where(t => ReferenceEquals(null, t.temp) || t.temp.Equals(default(T)))
.Select(t => t.t.item);
}
}
Here’s my unit test :
using (var context = new InMemoryDataBaseContext())
{
// Arrange
var repository = new UserRepository(context);
await context.Users.AddRangeAsync(GetUser());
await context.SaveChangesAsync();
// Act
var manyIds = new List<Guid>();
manyIds.Add(Guid.Parse("855d1a64-a707-40d5-ab93-34591a923abf"));
manyIds.Add(Guid.Parse("855d1a64-a787-40d9-ac93-34591a923abf"));
manyIds.Add(Guid.Parse("855d1a64-a707-41d9-ab93-39591a923abf"));
var user = new User();
var expected = repository.UpdateUserManyToMany(GetUser(), manyIds);
// Assert
}
But I get the following error in my test :
Message:
System.InvalidOperationException : The instance of entity type 'ManyToMany' cannot be tracked because another instance with the same key value for {'UserId', 'OtherEntityId'} is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the conflicting key values.
Arborescence des appels de procédure:
IdentityMap`1.ThrowIdentityConflict(InternalEntityEntry entry)
IdentityMap`1.Add(TKey key, InternalEntityEntry entry, Boolean updateDuplicate)
IdentityMap`1.Add(TKey key, InternalEntityEntry entry)
NullableKeyIdentityMap`1.Add(InternalEntityEntry entry)
StateManager.StartTracking(InternalEntityEntry entry)
InternalEntityEntry.SetEntityState(EntityState oldState, EntityState newState, Boolean acceptChanges, Boolean modifyProperties)
InternalEntityEntry.SetEntityState(EntityState entityState, Boolean acceptChanges, Boolean modifyProperties, Nullable`1 forceStateWhenUnknownKey)
EntityGraphAttacher.PaintAction(EntityEntryGraphNode`1 node)
EntityEntryGraphIterator.TraverseGraph[TState](EntityEntryGraphNode`1 node, Func`2 handleNode)
EntityGraphAttacher.AttachGraph(InternalEntityEntry rootEntry, EntityState targetState, EntityState storeGeneratedWithKeySetTargetState, Boolean forceStateWhenUnknownKey)
DbContext.SetEntityState(InternalEntityEntry entry, EntityState entityState)
DbContext.RemoveRange(IEnumerable`1 entities)
InternalDbSet`1.RemoveRange(IEnumerable`1 entities)
ManyToManyExtensions.TryUpdateManyToMany[T,TKey](DbContext db, IEnumerable`1 currentItems, IEnumerable`1 newItems, Func`2 getKey) ligne 24
UserRepository.UpdateUserManyToMany(User user, List`1 manyToManyds) ligne 59
MyRepoUnitTest.MyTestMethod() ligne 102
--- End of stack trace from previous location where exception was thrown ```

Answer 1

The following sample program, that is based on the code you provided, works without issues:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
namespace IssueConsoleTemplate
{
public class User
{
public Guid Id { get; set; }
public string Name { get; set; }
public ICollection<ManyToMany> ManyToMany { get; set; } = new HashSet<ManyToMany>();
}
public class OtherEntity
{
public Guid Id { get; set; }
public string Name { get; set; }
public ICollection<ManyToMany> ManyToMany { get; set; } = new HashSet<ManyToMany>();
}
public class ManyToMany
{
public Guid OtherEntityId { get; set; }
public Guid UserId { get; set; }
public OtherEntity OtherEntity { get; set; }
public User User { get; set; }
}
public class Context : DbContext
{
public DbSet<OtherEntity> OtherEntities { get; set; }
public DbSet<User> Users { get; set; }
public DbSet<ManyToMany> ManyToMany { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder
.UseSqlServer(#"Data Source=.\MSSQL14;Integrated Security=SSPI;Initial Catalog=So63077461")
.UseLoggerFactory(
LoggerFactory.Create(
b => b
.AddConsole()
.AddFilter(level => level >= LogLevel.Information)))
.EnableSensitiveDataLogging()
.EnableDetailedErrors();
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<OtherEntity>(
entity =>
{
entity.HasKey(e => e.Id);
entity.HasMany(e => e.ManyToMany)
.WithOne(e => e.OtherEntity)
.HasForeignKey(e => e.OtherEntityId);
entity.HasData(
new OtherEntity
{
Id = new Guid("855d1a64-a707-40d5-ab93-34591a923abf"),
Name = "Bicycle"
},
new OtherEntity
{
Id = new Guid("855d1a64-a787-40d9-ac93-34591a923abf"),
Name = "Bus"
},
new OtherEntity
{
Id = new Guid("855d1a64-a707-41d9-ab93-39591a923abf"),
Name = "Plane"
});
});
modelBuilder.Entity<User>(
entity =>
{
entity.HasKey(e => e.Id);
entity.HasMany(e => e.ManyToMany)
.WithOne(e => e.User)
.HasForeignKey(e => e.UserId);
});
modelBuilder.Entity<ManyToMany>(
entity =>
{
entity.HasKey(e => new {e.OtherEntityId, e.UserId});
});
}
}
public static class ManyToManyExtensions
{
public static void TryUpdateManyToMany<T, TKey>(this DbContext db, IEnumerable<T> currentItems, IEnumerable<T> newItems, Func<T, TKey> getKey) where T : class
{
db.Set<T>().RemoveRange(currentItems.Except(newItems, getKey));
db.Set<T>().AddRange(newItems.Except(currentItems, getKey));
}
public static IEnumerable<T> Except<T, TKey>(this IEnumerable<T> items, IEnumerable<T> other, Func<T, TKey> getKeyFunc)
{
return items
.GroupJoin(other, getKeyFunc, getKeyFunc, (item, tempItems) => new { item, tempItems })
.SelectMany(t => t.tempItems.DefaultIfEmpty(), (t, temp) => new { t, temp })
.Where(t => ReferenceEquals(null, t.temp) || t.temp.Equals(default(T)))
.Select(t => t.t.item);
}
}
internal class UserRepository
{
private readonly Context _databaseContext;
public UserRepository(Context context)
{
_databaseContext = context;
}
public User UpdateUserManyToMany(User user, List<Guid> manyToManyds)
{
var dbContext = _databaseContext as DbContext;
dbContext?.TryUpdateManyToMany(user.ManyToMany, manyToManyds
.Select(x => new ManyToMany{
OtherEntityId = x,
UserId = user.Id,
}), x => x.OtherEntityId);
return user;
}
}
internal static class Program
{
private static async Task Main()
{
//
// Operations with referential integrity intact:
//
using var context = new Context();
context.Database.EnsureDeleted();
context.Database.EnsureCreated();
// Arrange
var repository = new UserRepository(context);
await context.Users.AddRangeAsync(GetUser());
await context.SaveChangesAsync();
// Act
var manyIds = new List<Guid>
{
new Guid("855d1a64-a707-40d5-ab93-34591a923abf"),
new Guid("855d1a64-a787-40d9-ac93-34591a923abf"),
new Guid("855d1a64-a707-41d9-ab93-39591a923abf")
};
var expected = repository.UpdateUserManyToMany(GetUser(), manyIds);
}
private static User GetUser()
=> User;
private static readonly User User = new User
{
Id = new Guid("30c35d2e-77fd-480b-9974-6ebf037a8f86"),
Name = "John"
};
}
}
System.InvalidOperationException : The instance of entity type 'ManyToMany' cannot be tracked because another instance with the same key value for {'UserId', 'OtherEntityId'} is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the conflicting key values.
The error message says, that at least one of your ManyToMany entries already exists in the database (there is an entry with the same UserId and OtherEntityId combination).
You can verify this, by running the following code directly after your filled the manyIds variable with the 3 IDs:
var user = GetUser();
var alreadyExistingManyToMany = context.ManyToMany
.Where(m => m.UserId == user.Id &&
manyIds.Contains(m.OtherEntityId))
.ToList();
Debug.Assert(alreadyExistingManyToMany.Count == 0);