public void Backup1()
{
BuildItemGroup group = new BuildItemGroup(); // virtual group
XmlElement element = CreatePersistedItemGroupElement();
BuildItem item1 = CreatePersistedBuildItem(element, "i", "i1");
BuildItem item2 = CreatePersistedBuildItem(element, "i", "i2");
group.AddExistingItem(item1);
group.AddExistingItem(item2);
BuildItem item3 = group.AddNewItem("j", "j1"); // virtual
Assertion.AssertEquals(3, group.Count);
group.RemoveItemWithBackup(item3);
group.RemoveItemWithBackup(item1);
Assertion.AssertEquals(1, group.Count);
group.RemoveAllIntermediateItems();
Assertion.AssertEquals(2, group.Count);
}