currently, the repository contains an instance of bats here. bats does not exist in the form it did when this was first done, but bats-core exists as the spiritual successor, is largely backwards compatible, and is actively maintained.
It should be possible to install bats-core and remove the src/epmt/test/integration/libs folder from the repository completely.
a working epmt integration step/test in the pipeline assists with accomplishing this a lot.