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.

I pass strings that I parse sometimes, and I think it reads pretty well.

Example:

[TestCase("15°", "-10°", 25, typeof(Degrees))]
[TestCase("-10°", "15°", -25, typeof(Degrees))]
[TestCase("-10°", "0°", -10, typeof(Degrees))]
[TestCase("-90°", "1.5707 rad", -3.1414, typeof(Radians))]
[TestCase("1.5707 rad", "-90°", 3.1414, typeof(Radians))]
[TestCase("1.5707 rad", "1.5707 rad", 0, typeof(Radians))]
public void SubtractionTest(string lvs, string rvs, double ev, Type et)
{
    var lv = Angle.Parse(lvs);
    var rv = Angle.Parse(rvs);
    var diff = lv - rv;
    Assert.AreEqual(ev, diff.Value, 1e-3);
    Assert.AreEqual(et, diff.Unit.GetType());
}