public async Task MaxAsync_WithSelector()
        {
            EntityMapping.RegisterType(typeof(QueryableAsyncModel));

            var connection = TestConfiguration.GetConnection();
            var context    = new MongoDbContext(connection);
            var provider   = new MongoFrameworkQueryProvider <QueryableAsyncModel>(connection);
            var queryable  = new MongoFrameworkQueryable <QueryableAsyncModel>(provider);

            context.ChangeTracker.SetEntityState(new QueryableAsyncModel {
                Title = "MaxAsync_WithSelector.1", IntNumber = 10
            }, EntityEntryState.Added);
            context.ChangeTracker.SetEntityState(new QueryableAsyncModel {
                Title = "MaxAsync_WithSelector.2", IntNumber = 20
            }, EntityEntryState.Added);
            context.SaveChanges();

            var result = await queryable.MaxAsync(e => e.IntNumber);

            Assert.AreEqual(20, result);
        }