public void ArrayElemAt()
 {
     Aggregate(_pl.Project(x => new { Result = x.StringArray[1] }))
     .First()
     .Result.Should()
     .Be(_item.StringArray[1]);
 }
 public void Abs()
 {
     Aggregate(_pipeline.Project(x => new { Result = Math.Abs(x.Value) }))
     .Should().Contain(x => x.Result == 10);
 }
 public void And()
 {
     Aggregate(_pipeline.Project(x => new { Result = x.Value > 50 && x.Value > 75 }))
     .Should().Contain(x => x.Result);
 }
 public void Concat()
 {
     Aggregate(_pl.Project(x => new { Result = x.Name + ":" + x.Body }))
     .First().Result.Should().Be("A.b.C:1");
 }