public void TryFirst_WherePredicateMatchesNoItems_ReturnsNoValue()
{
IEnumerable<string> source = new[] { "Foo", "Baz", "Boo", "Quix" };
var result = source.TryFirst(x => false);
Assert.IsFalse(result.HasValue);
}
public void TryFirst_WithFirstItemNull_ReturnsNoValue()
{
IEnumerable<string> source = new[] { null, "Foo", "Baz" };
var result = source.TryFirst();
Assert.IsFalse(result.HasValue);
result = source.TryFirst(x => true);
Assert.IsFalse(result.HasValue);
}
public void TryFirst_WherePredicateMatchesItem_ReturnsFirstMatchingItem()
{
IEnumerable<string> source = new[] { "Foo", "Baz", "Boo", "Quix" };
var result = source.TryFirst(x => x.StartsWith("B"));
Assert.IsTrue(result.HasValue);
Assert.AreEqual("Baz", result.Value);
}
public void TryFirst_WithManyItems_ReturnsFirstItem()
{
IEnumerable<int> source = new[] { 42, 84, 168 };
var result = source.TryFirst();
Assert.IsTrue(result.HasValue);
Assert.AreEqual(42, result.Value);
result = source.TryFirst(x => true);
Assert.IsTrue(result.HasValue);
Assert.AreEqual(42, result.Value);
}
