public void SelectAnonymousProjectionTranslatesToNestedField()
        {
            var RobotsWithOs = new ElasticQuery <RobotWithOs>(SharedProvider);

            var selected      = RobotsWithOs.Select(r => new { r.OperatingSystem.Name });
            var searchRequest = ElasticQueryTranslator.Translate(Mapping, selected.Expression).SearchRequest;

            Assert.Equal("robotwithos", searchRequest.IndexType);
            Assert.NotNull(searchRequest.Fields);
            Assert.Contains("operatingSystem.name", searchRequest.Fields);
            Assert.Equal(1, searchRequest.Fields.Count);
        }