public void TryLast_WherePredicateMatchesNoItems_ReturnsNoValue()
{
IEnumerable<string> source = new[] { "Foo", "Baz", "Boo", "Quix" };
var result = source.TryLast(x => false);
Assert.IsFalse(result.HasValue);
}
public void TryLast_WherePredicateMatchesItem_ReturnsLastMatchingItem()
{
IEnumerable<string> source = new[] { "Foo", "Baz", "Boo", "Quix" };
var result = source.TryLast(x => x.StartsWith("B"));
Assert.IsTrue(result.HasValue);
Assert.AreEqual("Boo", result.Value);
}
public void TryLast_WithManyItems_ReturnsLastItem()
{
IEnumerable<int> source = new[] { 42, 84, 168 };
var result = source.TryLast();
Assert.IsTrue(result.HasValue);
Assert.AreEqual(168, result.Value);
result = source.TryLast(x => true);
Assert.IsTrue(result.HasValue);
Assert.AreEqual(168, result.Value);
}
public void TryLast_WithLastItemNull_ReturnsNoValue()
{
IEnumerable<string> source = new[] { "Foo", "Baz", null };
var result = source.TryLast();
Assert.IsFalse(result.HasValue);
result = source.TryLast(x => true);
Assert.IsFalse(result.HasValue);
}
public void TryLast_WithOneItem_ReturnsItem()
{
IEnumerable<int> source = new[] { 42 };
var result = source.TryLast();
Assert.IsTrue(result.HasValue);
Assert.AreEqual(42, result.Value);
result = source.TryLast(x => true);
Assert.IsTrue(result.HasValue);
Assert.AreEqual(42, result.Value);
}