EmptyCollection Constraint

EmptyCollectionConstraint tests that an IEnumerable contains no items. An ArgumentException is thrown if the actual value is not an IEnumerable or is null.

Usage

Is.Empty
Is.Not.Empty

Examples

[Test]
public void EmptyCollectionConstraint_Examples()
{
    // Empty collections
    Assert.That(new int[] { }, Is.Empty);
    Assert.That(new List<string>(), Is.Empty);
    Assert.That(Array.Empty<int>(), Is.Empty);
    Assert.That(Enumerable.Empty<string>(), Is.Empty);

    // Non-empty collections
    Assert.That(new[] { 1, 2, 3 }, Is.Not.Empty);
    Assert.That(new List<string> { "item" }, Is.Not.Empty);
}

Notes

  1. Is.Empty is a polymorphic constraint that works with strings, collections, and directories.
  2. When applied to an IEnumerable, it creates an EmptyCollectionConstraint internally.
  3. Passing null throws an ArgumentException. Use Is.Null.Or.Empty pattern if null is acceptable.

See Also