Range Constraint

RangeConstraint tests that a value falls within an inclusive range. Both the lower and upper bounds are included in the valid range.

Usage

Is.InRange(IComparable from, IComparable to)

Modifiers

.Using(IComparer comparer)
.Using<T>(IComparer<T> comparer)
.Using<T>(Comparison<T> comparer)

Examples

[Test]
public void RangeConstraint_Examples()
{
    // Numeric ranges (inclusive)
    Assert.That(5, Is.InRange(1, 10));
    Assert.That(1, Is.InRange(1, 10));   // Lower bound is included
    Assert.That(10, Is.InRange(1, 10));  // Upper bound is included
    Assert.That(0, Is.Not.InRange(1, 10));

    // DateTime ranges
    var start = new DateTime(2024, 1, 1);
    var end = new DateTime(2024, 12, 31);
    Assert.That(new DateTime(2024, 6, 15), Is.InRange(start, end));

    // String ranges (alphabetical comparison)
    Assert.That("banana", Is.InRange("apple", "cherry"));
}

Notes

  1. The range is inclusive on both ends: Is.InRange(1, 10) passes for values 1, 10, and everything in between.

  2. For exclusive bounds, combine Is.GreaterThan and Is.LessThan with And:

    Assert.That(5, Is.GreaterThan(1).And.LessThan(10));  // Exclusive bounds

See Also