public void TestCombineUnion()
{
CollectionAssert.AreEqual(Empty, CombineAnnotationColumns.Union(None));
CollectionAssert.AreEqual(new [] { "a", "b" }, CombineAnnotationColumns.Union(Some));
CollectionAssert.AreEqual(new [] { "a", "b", "c" }, CombineAnnotationColumns.Union(Full));
}
