DictionaryContainsKeyValuePair Constraint

DictionaryContainsKeyValuePairConstraint tests whether a dictionary contains a specific key-value pair.

Usage

Does.ContainKey(object key).WithValue(object value)
Does.Not.ContainKey(object key).WithValue(object value)

Modifiers

These modifiers apply to the value comparison:

.IgnoreCase
.IgnoreWhiteSpace              // NUnit 4.2+
.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 DictionaryContainsKeyValuePairConstraint_Examples()
{
    var translations = new Dictionary<string, string>
    {
        ["Hello"] = "World",
        ["Hola"] = "Mundo"
    };

    // Check for specific key-value pair
    Assert.That(translations, Does.ContainKey("Hello").WithValue("World"));
    Assert.That(translations, Does.ContainKey("Hola").WithValue("Mundo"));

    // Negative: key exists but value doesn't match
    Assert.That(translations, Does.Not.ContainKey("Hello").WithValue("Universe"));

    // Case-insensitive value comparison
    Assert.That(translations, Does.ContainKey("Hello").WithValue("WORLD").IgnoreCase);
}

Notes

  1. Key comparison uses the dictionary's comparer (cannot be overridden).
  2. Value comparison modifiers (.IgnoreCase, .Using(), etc.) only apply to the value.
  3. The preferred syntax is Does.ContainKey(key).WithValue(value) rather than the constructor form.

See Also