Moved all of DeltaSubscriptionImpl's existing tests to be DeltaSubscriptionState tests, since that's what they really were. Added tests that test actual DeltaSubscriptionImpl logic. Followup of #6729.
Risk Level: none, just adding tests
Testing: DeltaSubscriptionState, DeltaSubscriptionImpl
Signed-off-by: Fred Douglas <fredlas@google.com>
Mirrored from https://github.com/envoyproxy/envoy @ ae3106b3ee792f697b2098781a0e65d8d73a32ca