So overall I would say that if you want to test bots, do not test them at different times, always have bots working at the same time on different accounts to see which one is doing better than the others at the same period of time. That would be a lot more fair to bots you test during bear markets versus the bots you test during bull markets.
Unfortunately, I don't have the resources to check all the bots simultaneously with the real money deposits. You are right, the market could both help bots to show the results or ruin the action. I am testing Bitsgap bot for almost a year, and during this period there were different market movements. By the way here is my latest Bitsgap grid trading bot report.
Another bot solution I am testing right now, which is Cryptohopper is also running for already 1 month and I going to give it some time to understand how does it perform during different market movements.
Trading bot - is a tool. So the initial goal of these testings is to understand if these tools have the settings needed for a profitable automated trading. Are there any errors happening, how does the customer support work and so on.