Test Sets and Tests are searchable within collections. The IDesign interface supports direct recasting into an ITestSetCollection, whereby any Test Set can then be searched for by Name, ID or Index. Once Test Sets are found, the ITestSet supports a collection-style interface that allows Tests to be searched for by Name, ID or Index. This is the Drill-Down process for Tests Sets and Tests. Parent interfaces are searchable by using the IExpressEntity interface.