We had a multi-tenant system with billions of tenants. We just spun up a new tenant and tested there. Unit tests had their own isolated environment, but there w

We had a multi-tenant system with billions of tenants. We just spun up a new tenant and tested there. Unit tests had their own isolated environment, but there was no reason to worry about a 'safe' environment. If you managed to break production, you likely knew exactly what you did to break it (and can at least tell someone about it).