Is it possible to keep NDbUnit test data in separate XML files?

I'm looking at using NDbUnit to help with the unit testing of an application. As the question title states, I'm wondering if it is possible to keep NDbUnit test data in separate XML files. I have noticed already that my single test data XML file is quite big and could start to become unmanageable when I add a few more entities to it.

Now, having read this question it looks as if it's not possible but I would just like to be sure.

If it helps, this is sample code which illustrates the problem. The idea is that programs are associated with vendors. I have set up test data containing 3 vendors, the second one of which has 3 programs. TestData.xml contains all of the test data for all of the vendors and programs. When I use it, the unit test passes as expected. If I try to read the individual XML file in separately using multiple calls to db.PerformDbOperation(DbOperationFlag.CleanInsertIdentity); it seems as if the second call overwrites whatever was done in the first one.

private const string xmlSchema = @"..\..\schema.xsd";
// All of the test data in one file.
private con开发者_StackOverflow社区st string xmlData = @"..\..\XML Data\TestData.xml";
// Individual test data files.
private const string vendorData = @"..\..\XML Data\Vendor_TestData.xml";
private const string programData = @"..\..\XML Data\Program_TestData.xml";

public void WorkingExampleTest()
{
    INDbUnitTest db = new SqlDbUnitTest(connectionString);
    db.ReadXmlSchema(xmlSchema);
    db.ReadXml(xmlData);
    db.PerformDbOperation(DbOperationFlag.CleanInsertIdentity);

    VendorCollection vendors = VendorController.List();
    Assert.IsNotNull(vendors);

    ProgramCollection collection = VendorController.GetPrograms(vendors[1].VendorID);
    Assert.IsNotNull(collection);
    Assert.IsTrue(collection.Count == 3);
}

public void NotWorkingExampleTest()
{
    INDbUnitTest db = new SqlDbUnitTest(connectionString);
    db.ReadXmlSchema(xmlSchema);
    db.ReadXml(vendorData);
    db.PerformDbOperation(DbOperationFlag.CleanInsertIdentity);

    db.ReadXml(programData);
    db.PerformDbOperation(DbOperationFlag.CleanInsertIdentity);

    VendorCollection vendors = VendorController.List();
    Assert.IsNotNull(vendors);

    // This line throws an ArgumentOutOfRangeException because there are no vendors in the collection.
    ProgramCollection collection = VendorController.GetPrograms(vendors[1].VendorID);
    Assert.IsNotNull(collection);
    Assert.IsTrue(collection.Count == 3);
}

This does work:

Watch out for the meaning of the DbOperationFlag value you are using; the "Clean" part of "CleanInsertIdentity" means "clean out the existing records before performing the insert-identity part of the process".

See http://code.google.com/p/ndbunit/source/browse/trunk/NDbUnit.Core/DbOperationFlag.cs for more info on the possible enum values.

You might try the same process with either Insert or InsertIdentity to see if you can achieve what you are after, but by design CleanInsertIdentity isn't going to work for this scenario :)