public void CacheDictionary_Enumerate()
{
var cd = new CacheDictionary<string, int>(EqualityComparer<string>.Default);
cd.GetOrAdd("foo", s => s == null ? 0 : s.Length);
cd.GetOrAdd(key: null, s => s == null ? 0 : s.Length);
var res = cd.ToArray();
Assert.AreEqual(2, res.Length);
Assert.IsTrue(res.Any(x => x.Key == null && x.Value == 0));
Assert.IsTrue(res.Any(x => x.Key == "foo" && x.Value == 3));
Assert.IsNotNull(((IEnumerable)cd).GetEnumerator());
}