EF Core InMemory DB foreign keys checker

DbForeignKeysChecker.cs

public static class DbForeignKeysChecker
    {
        private static readonly Dictionary<DbContext, Dictionary<Type, Keys>> KeysPerEntityTypeOfContext = new Dictionary<DbContext, Dictionary<Type, Keys>>();

        public static void SaveChangesWithCheck(this DbContext context)
        {
            context.SaveChanges();
            context.CheckForeignKeys();
        }

        private static void CheckForeignKeys(this DbContext db)
        {
            if (!KeysPerEntityTypeOfContext.ContainsKey(db))
            {
                KeysPerEntityTypeOfContext[db] = db.Model
                    .GetEntityTypes()
                    .Where(x => !x.IsOwned())
                    .ToDictionary(
                        x => x.ClrType,
                        x => new Keys
                        {
                            PrimaryKeyProperties = x.FindPrimaryKey().Properties.Select(p => p.PropertyInfo).ToList(),
                            ForeignKeys = x.GetForeignKeys()
                                .Where(z => !z.IsOwnership)
                                .Select(z => new ForeignKey
                                {
                                    PrincipalType = z.PrincipalEntityType.ClrType,
                                    PrincipalPropName = z.DependentToPrincipal.Name,
                                    Properties = z.Properties.Select(p => p.PropertyInfo ?? throw new Exception($"No FK property info (from {x.ClrType} to {z.PrincipalEntityType.ClrType})")).ToList()
                                })
                                .ToList()
                        }
                    );
            }
            var dbSets = db.GetType().GetProperties()
                .Where(x => x.PropertyType.IsGenericType && x.PropertyType.GetGenericTypeDefinition() == typeof(DbSet<>))
                .Select(x => new Set
                {
                    EntityType = x.PropertyType.GetGenericArguments()[0],
                    List = x.GetValue(db) as IEnumerable<dynamic>
                })
                .Where(x => x.List != null)
                .ToList();

            var keysPerEntityType = KeysPerEntityTypeOfContext[db];
            foreach (var dbSet in dbSets)
            {
                var foreignKeys = keysPerEntityType[dbSet.EntityType].ForeignKeys;
                foreach (var fk in foreignKeys)
                {
                    var dbSetOfPrincipal = dbSets.FirstOrDefault(x => x.EntityType == fk.PrincipalType);
                    if (dbSetOfPrincipal == null)
                    {
                        throw new Exception($"FK validation failed: DbSet<{fk.PrincipalType.Name}> is null");
                    }

                    var principalPrimaryKeysProps = keysPerEntityType[fk.PrincipalType].PrimaryKeyProperties;
                    foreach (var entity in dbSet.List)
                    {
                        var fkPropsValues = fk.Properties.Select(x => x.GetValue(entity)).ToList();
                        if (fkPropsValues.All(x => x != null) &&
                            dbSetOfPrincipal.List.FirstOrDefault(x => principalPrimaryKeysProps.Select(z => z.GetValue(x)).SequenceEqual(fkPropsValues)) == null)
                        {
                            throw new Exception($"FK validation failed: checking DbSet<{dbSet.EntityType.Name}>, principal {fk.PrincipalPropName}({fk.PrincipalType.Name}) with key '{fkPropsValues.ToSeparatedString()}' not found");
                        }
                    }
                }
            }
        }

        private class Keys
        {
            public List<PropertyInfo> PrimaryKeyProperties { get; set; }
            public List<ForeignKey> ForeignKeys { get; set; }
        }

        private class ForeignKey
        {
            public Type PrincipalType { get; set; }
            public string PrincipalPropName { get; set; }
            public List<PropertyInfo> Properties { get; set; }
        }

        private class Set
        {
            public Type EntityType { get; set; }
            public IEnumerable<dynamic> List { get; set; }
        }
    }