due to circular imports issues and me going out of my way to make it work 'cleanly', the previous backwards compatibility for FrappeTestCase unfortunately did not work on the manual cli test runner 'run-tests'
While not generally not affecting CI (which is precedented by the framwork's best practices to use 'run-parallel-test'), this broke some manual developer workflows
The restauration of FrappeTestCase in these scenario now unfortunately involves a plain copy of almost an entire implementation into the dumpster.
On the one hand, this doesn not accurately reflect the rather minuscule differences between IntegrationTestCase and FrappeTestCase, but on the other hand, it shields and freezes the old api should IntegrationTestCase evolve futher
