EmptyString Constraint

EmptyStringConstraint tests that a string has zero length. This is a specialized constraint created when Is.Empty is applied to a string value.

Usage

Is.Empty
Is.Not.Empty

Examples

[Test]
public void EmptyStringConstraint_Examples()
{
    Assert.That("", Is.Empty);
    Assert.That(string.Empty, Is.Empty);
    Assert.That("Hello", Is.Not.Empty);

    // Common pattern: check for null or empty
    string? result = "";
    Assert.That(result, Is.Null.Or.Empty);

    string name = "Alice";
    Assert.That(name, Is.Not.Null.And.Not.Empty);
}

Notes

  1. Is.Empty is a polymorphic constraint that tests for empty strings, collections, or directories depending on the actual value type.
  2. For checking null-or-empty strings, you can combine constraints: Is.Null.Or.Empty.
  3. To test for whitespace-only strings, use WhiteSpaceConstraint.

See Also