I've done a thing automating whole environment setups with VMware cloning (undocumented feature because there is it's own product on top of it) and Docker via CI, in a bank. Basically we did golden images of VMs with databases having all accounts for test cases and prepared images for services to be deployed, while getting all necessary variables from CI and VSphere to write down in configs and Consul/Vault via scripts. Initial version control for the env could be done via same prefixes in the Git branches of services, after the deployment each env had a way to deploy whatever via CI's Web UI or API.

Running automated integration tests on the whole env is just an added step in the pipeline.