How can I pass dynamic objects into an NUnit TestCase function?

I tracked it down. I can’t pass an instantiated object into a test via TestCase because attributes are strictly for static meta-data. But the NUnit team has a solution for that, TestCaseSource. The post on the NUnit list that answered the question is here.

Here is what my solution now looks like:

public static IEnumerable<TestCaseData> CountEqualsZeroAndHouseGrossIsGreaterTestCases
{
    get
    {
        yield return new TestCaseData(report, report.Merchants[4268435971532164].LineItem["EBTPerItem"], 4268435971532164, "EBTPerItem").SetName("ReportMerchantsLineItem");
        yield return new TestCaseData(report, report.Merchants[5461324658456716].AggregateTotals, 5461324658456716, "WirelessPerItem").SetName("ReportMerchantsAggregateTotals");
        yield return new TestCaseData(report, report.AggregateTotals, null, "AggregateTotals").SetName("ReportAggregateTotals");
        yield return new TestCaseData(report, report.AggregateTotals.LineItem["WirelessPerItem"], null, "WirelessPerItem").SetName("ReportAggregateTotalsLineItem");
    }
}


[TestCaseSource("CountEqualsZeroAndHouseGrossIsGreaterTestCases")]
public void DoSanityCheck_WithCountEqualsZeroAndHouseGrossIsGreater_TestCase_SetsWarning(Reports.ResidualsReport report, Reports.LineItemObject container, long? mid, string field)
{
    container.ItemCount = 0;
    container._volume = 0;
    container._houseGross = 1;

    report.DoSanityCheck();

    Assert.IsTrue(report.FishyFlag);
    Assert.That(report.DataWarnings.Where(x=> x is Reports.WarningObjects.ImbalancedVariables && x.mid == mid && x.lineitem == field).Count() > 0);
}

It is not as pretty as I hoped and is not as easy to read. But it did succeed on cutting down code duplication, which should make things easier to maintain and fix.