Is there an Ethereum network simulator that does things like gas price swings, many other transactions submitted, etc? I'm aware of running things like geth or ganache but as far as I can tell they don't really have modes that simulate what an actual network can look like. (Am I wrong? It'd be great if there were just some flags to either of those that could be used.)
I'm not talking about connecting to something like Ropsten, I'm talking about a private network that can be controlled and manipulated (and probably replayed) for use in tests.