Does lockdown work in reverse for the 2nd wave?

So I understand how the social distancing and lock-down works on the front-end of a disease outbreak to slow the rate of infection.

What I was just wondering is if it works in the reverse for the second wave of infection? Everyone’s talking about a resurgence/second-wave of COVID-19 in the community once restrictions are eased, due to increased community transmission.

So what I’m wondering is that if we stay locked down and the transmission rate is lower, does that mean that the longer we stay locked down, the fewer people will be able to start the community transmission back up, thereby giving us a longer lead-time on that second wave?

My understanding is that theoretically, the real difference in a second wave is that we would have testing capacity enough to test quickly and effectively–thus limiting the second wave. We had to keep well people away from sick people because we didn’t know who the sick people were. If we can identify them, it’s a whole different thing. So you shouldn’t open up until you can test.