public void IsEmptyTest()
{
string tag = "100";
DataField target = new DataField(tag);
bool expected = true;
bool actual = target.IsEmpty();
Assert.AreEqual(expected, actual);
List <Subfield> subfields = new List <Subfield>();
Subfield subfield = new Subfield('a', "It's a book!");
subfields.Add(subfield);
subfield = new Subfield('b', "Anne Author");
subfields.Add(subfield);
subfield = new Subfield('b', "Anne Otter Author");
subfields.Add(subfield);
target = new DataField(tag, subfields);
expected = false;
actual = target.IsEmpty();
Assert.AreEqual(expected, actual);
}