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(IComparer comparer)
.Using(Comparison 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