public void Single_Include_Only_Should_Equal_Output() { var context = new PartialPatientCountContext[] { new PartialPatientCountContext { PatientIds = new HashSet <string> { "123", "234", "345", "456" }, IsInclusionCriteria = true } }; var agg = new PatientCountAggregator().Aggregate(context); Assert.True(agg.SequenceEqual(context.ElementAt(0).PatientIds)); }