public void HeadReturnsNullOnEmptyList()
{
int?expected = null;
var emptyList = OkasakiList.empty <int>();
var actual = OkasakiList.head <int>(emptyList);
Assert.AreEqual(expected, actual);
}
public void HeadReturnsCorrectValueForSingleton()
{
var value = 12;
var singletonList = OkasakiList.singleton(value);
int?expected = value;
var actual = OkasakiList.head(singletonList);
Assert.AreEqual(expected, actual);
}
public void HeadReturnsCorrectValueForList()
{
var value1 = 1;
var value2 = 2;
var value3 = 3;
//we load up the list in reverse order, since basic cons inserts at the head
var olist1 = OkasakiList.singleton(value3);
var olist2 = OkasakiList.cons(value2, olist1);
var olist3 = OkasakiList.cons(value1, olist2);
var expected = value1;
var actual = OkasakiList.head(olist3);
Assert.AreEqual(expected, actual);
}