func TestDatastoreKeyChangingIDInvalidatesCache(t *testing.T) {
people := CreateTestModel()
person := people.New()
var key *datastore.Key = person.DatastoreKey()
person.setID(123)
var keyAfterID *datastore.Key = person.DatastoreKey()
if key.Eq(keyAfterID) {
t.Errorf("Key cache should be invalidated after setID is called")
}
}