How do you handle collections in NUnit assertions?

NUnit provides specialized assertions for collections using CollectionAssert and constraint syntax.

Collection Assertions:

[Test]
public void TestCollections()
{
    var numbers = new[] { 1, 2, 3, 4, 5 };
    var expected = new[] { 1, 2, 3, 4, 5 };
    
    // Collection equality
    Assert.That(numbers, Is.EqualTo(expected));
    
    // Contains element
    Assert.That(numbers, Contains.Item(3));
    
    // Collection size
    Assert.That(numbers, Has.Length(5));
    Assert.That(numbers, Has.Count.EqualTo(5));
    
    // All items match condition
    Assert.That(numbers, Is.All.GreaterThan(0));
    
    // Using CollectionAssert
    CollectionAssert.AreEqual(expected, numbers);
    CollectionAssert.Contains(numbers, 3);
    CollectionAssert.IsSubsetOf(new[] { 1, 2 }, numbers);
}