/// <summary>
/// Helper for testing empty dictionary
/// </summary>
/// <typeparam name="TKey">type of dictionary key</typeparam>
/// <typeparam name="TValue">type of dictionary value</typeparam>
private static void TestEmptyDictionaty <TKey, TValue>()
{
// Singleton test
var instance1 = Empty.GetDictionary <TKey, TValue>();
Assert.IsNotNull(instance1);
var instance2 = Empty.GetDictionary <TKey, TValue>();
Assert.IsNotNull(instance2);
Assert.IsTrue(object.ReferenceEquals(instance1, instance2));
// Count
Assert.AreEqual(0, instance1.Count);
// enumerator
var hasValue = false;
foreach (var pair in instance1)
{
hasValue = true;
}
Assert.IsFalse(hasValue);
// cast test
Assert.IsNull(instance1 as IDictionary <TKey, TValue>);
}