NaN Constraint

NaNConstraint tests that a floating-point value is NaN (Not a Number).

Usage

Is.NaN
Is.Not.NaN

Examples

[Test]
public void NaNConstraint_Examples()
{
    // NaN results from undefined operations
    Assert.That(double.NaN, Is.NaN);
    Assert.That(float.NaN, Is.NaN);
    Assert.That(0.0 / 0.0, Is.NaN);
    Assert.That(Math.Sqrt(-1), Is.NaN);

    // Regular numbers are not NaN
    Assert.That(42.0, Is.Not.NaN);
    Assert.That(double.PositiveInfinity, Is.Not.NaN);
    Assert.That(double.NegativeInfinity, Is.Not.NaN);
}

Notes

  1. NaN is the only value that is not equal to itself (NaN != NaN is true).
  2. Both double.NaN and float.NaN are supported.
  3. Infinity values are not NaN.

See Also