CollectionSuperset Constraint

CollectionSupersetConstraint tests that one IEnumerable is a superset of another. Every item in the expected collection must be present in the actual collection. An exception is thrown if the actual value does not implement IEnumerable.

Usage

Is.SupersetOf(IEnumerable expected)

Modifiers

.Using(IComparer comparer)
.Using(IEqualityComparer comparer)
.Using<T>(IComparer<T> comparer)
.Using<T>(IEqualityComparer<T> comparer)
.Using<T>(Comparison<T> comparer)
.Using<T>(Func<T, T, bool> comparer)
.UsingPropertiesComparer()     // NUnit 4.1+

Examples

[Test]
public void CollectionSupersetConstraint_Examples()
{
    int[] actual = { 1, 2, 3, 4, 5 };

    Assert.That(actual, Is.SupersetOf(new[] { 1, 3 }));       // Passes
    Assert.That(actual, Is.SupersetOf(new[] { 1, 2, 3, 4, 5 })); // Passes (equal sets)
    Assert.That(actual, Is.SupersetOf(new int[] { }));        // Passes (superset of empty)
    Assert.That(actual, Is.Not.SupersetOf(new[] { 1, 6 }));   // Passes (missing 6)

    // Case-insensitive string comparison
    string[] colors = { "Red", "Green", "Blue", "Yellow" };
    Assert.That(colors, Is.SupersetOf(new[] { "red", "blue" }).Using((IEqualityComparer<string>)StringComparer.OrdinalIgnoreCase));
}

Notes

  1. A set is always a superset of itself.
  2. Every set is a superset of the empty set.
  3. Duplicate items are considered: {1, 2} is not a superset of {1, 1}.

See Also