public static void TestItems()
{
ProgressContext progress = new ProgressContext();
Assert.That(progress.Items, Is.EqualTo(0), "At start there are no item counted.");
progress.AddItems(7);
Assert.That(progress.Items, Is.EqualTo(7), "There was just 7 added.");
progress.AddItems(-1);
Assert.That(progress.Items, Is.EqualTo(6), "Items are counted down by adding negative numbers.");
}
