private void AssertInvalidOperationsOnTraverserAtStartOrEnd(IListTraverser <int> traverser)
{
Assert.Throws <InvalidOperationException>(() => { var x = traverser.Index; });
Assert.Throws <InvalidOperationException>(() => { var x = traverser.Element; });
Assert.Throws <InvalidOperationException>(() => traverser.Element = 1);
Assert.Throws <InvalidOperationException>(() => traverser.RemoveAt());
}
private void AssertStateOfTraverserOnSingleElementList(IListTraverser <int> traverser)
{
// not asserting the value of the element, since that is test-case dependent
Assert.IsFalse(traverser.AtStart);
Assert.IsFalse(traverser.AtEnd);
Assert.IsTrue(traverser.OnElement);
Assert.IsTrue(traverser.OnIndex);
Assert.AreEqual(0, traverser.Index);
}
private void TestTraverserBackwardTraversal(IListTraverser <int> traverser)
{
for (int i = 4; i >= 0; --i)
{
Assert.AreEqual(i, traverser.Index);
Assert.AreEqual(i + 1, traverser.Element);
traverser.ToPrevious();
}
Assert.IsTrue(traverser.AtStart);
AssertInvalidOperationsOnTraverserAtStartOrEnd(traverser);
}
private void TestTraverserForwardTraversal(IListTraverser <int> traverser)
{
for (int i = 0; i < 5; ++i)
{
Assert.AreEqual(i, traverser.Index);
Assert.AreEqual(i + 1, traverser.Element);
traverser.ToNext();
}
Assert.IsTrue(traverser.AtEnd);
AssertInvalidOperationsOnTraverserAtStartOrEnd(traverser);
}
private void TestReplaceAndInsertOnSingleElementList(IListTraverser <int> traverser)
{
traverser.Element = 7;
Assert.IsTrue(Enumerable.SequenceEqual(new int[] { 7 }, m_list));
Assert.AreEqual(7, traverser.Element);
Assert.AreEqual(0, traverser.Index);
traverser.InsertBefore(4);
Assert.IsTrue(Enumerable.SequenceEqual(new int[] { 4, 7 }, m_list));
Assert.AreEqual(7, traverser.Element);
Assert.AreEqual(1, traverser.Index);
traverser.InsertAfter(10);
Assert.IsTrue(Enumerable.SequenceEqual(new int[] { 4, 7, 10 }, m_list));
Assert.AreEqual(7, traverser.Element);
Assert.AreEqual(1, traverser.Index);
}
private void AssertStateOfTraverserOnEmptyList(IListTraverser <int> traverser)
{
Assert.IsTrue(traverser.AtStart);
Assert.IsTrue(traverser.AtEnd);
Assert.IsFalse(traverser.OnElement);
Assert.IsFalse(traverser.OnIndex);
AssertInvalidOperationsOnTraverserAtStartOrEnd(traverser);
traverser.ToNext();
Assert.IsTrue(traverser.AtStart);
Assert.IsTrue(traverser.AtEnd);
Assert.IsFalse(traverser.OnElement);
Assert.IsFalse(traverser.OnIndex);
AssertInvalidOperationsOnTraverserAtStartOrEnd(traverser);
traverser.ToPrevious();
Assert.IsTrue(traverser.AtStart);
Assert.IsTrue(traverser.AtEnd);
Assert.IsFalse(traverser.OnElement);
Assert.IsFalse(traverser.OnIndex);
AssertInvalidOperationsOnTraverserAtStartOrEnd(traverser);
}
