fake/dummy implementation of mongodb IAsyncCursor used for testing

FakeAsyncCursor.cs

using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using MongoDB.Driver;

namespace MyProject.Test
{
    public class DummyAsyncCursor<TEntity> : IAsyncCursor<TEntity>
    {
        private readonly IEnumerable<TEntity> _items;
        private readonly IEnumerator<TEntity> _enumerator;

        public DummyAsyncCursor(IEnumerable<TEntity> items)
        {
            _items = items ?? Enumerable.Empty<TEntity>();
            _enumerator = items.GetEnumerator();
        }

        public IEnumerable<TEntity> Current
        {
            get { return _items; }
        }

        public Task<bool> MoveNextAsync(CancellationToken cancellationToken)
        {
            return Task.FromResult(_enumerator.MoveNext());
        }

        public void Dispose() { }

        public bool MoveNext(CancellationToken cancellationToken = default)
        {
            return _enumerator.MoveNext();
        }
    }
}