public void has_existing_entity()
{
var newIndex = new EntityIndex <ITestSecondPool, string>(Group, (e, c) => {
var nameAge = c as NameTestComponent;
return(nameAge != null
? nameAge.Name
: e.Get <NameTestComponent>().Name);
});
Assert.IsTrue(newIndex.HasEntities(Key));
Assert.AreEqual(2, newIndex.GetEntities(Key).Count);
}