In fact, I have the following error when I try to run the functional tests:

Executing functional tests in /home/ballot/charms/builds
functional create: /home/ballot/repos/charms/charm-k8s-telegraf/.tox/functional
functional installdeps: -r/home/ballot/repos/charms/charm-k8s-telegraf/tests/functional/requirements.txt
functional installed: appdirs==1.4.3,async-generator==1.10,bcrypt==3.2.0,CacheControl==0.12.6,certifi==2019.11.28,cffi==1.14.3,chardet==3.0.4,colorama==0.4.3,contextlib2==0.6.0,cryptography==3.2.1,debtcollector==2.2.0,distlib==0.3.0,distro==1.4.0,html5lib==1.0.1,hvac==0.6.4,idna==2.8,ipaddr==2.2.0,Jinja2==2.11.2,juju==2.8.4,juju-wait==2.8.4,jujubundlelib==0.5.6,lockfile==0.12.2,macaroonbakery==1.3.1,MarkupSafe==1.1.1,msgpack==0.6.2,mypy-extensions==0.4.3,netaddr==0.8.0,ops==1.0.1,oslo.config==6.11.2,oslo.i18n==5.0.1,packaging==20.3,paramiko==2.7.2,pbr==5.5.1,pep517==0.8.2,pkg-resources==0.0.0,progress==1.5,protobuf==3.13.0,pyasn1==0.4.8,pycparser==2.20,pymacaroons==0.13.0,PyNaCl==1.4.0,pyparsing==2.4.6,pyRFC3339==1.1,pytoml==0.1.21,pytz==2020.4,PyYAML==5.3.1,requests==2.22.0,retrying==1.3.3,rfc3986==1.4.0,six==1.14.0,stevedore==3.2.2,tenacity==6.2.0,theblues==0.5.2,toposort==1.5,typing-extensions==3.7.4.3,typing-inspect==0.6.0,urllib3==1.25.8,webencodings==0.5.1,websockets==7.0,wrapt==1.12.1,zaza==0.0.2.dev1
functional run-test-pre: PYTHONHASHSEED='3098041088'
functional run-test: commands[0] | functest-run-suite
2020-11-11 23:14:29 [WARNING] unknown delta type: id
2020-11-11 23:14:29 [INFO] Deploying bundle './tests/bundles/base.yaml' on to 'zaza-5567d93822fa' model
2020-11-11 23:14:29 [INFO] Rendered template '<Template 'local-charm-overlay.yaml.j2'>' to file '/tmp/tmp5z33c9e1/local-charm-overlay.yaml'
2020-11-11 23:14:29 [INFO] Deploying overlay '/tmp/tmp5z33c9e1/local-charm-overlay.yaml' on to 'zaza-5567d93822fa' model
2020-11-11 23:14:31 [INFO] ERROR cannot deploy bundle: the provided bundle has the following errors:
2020-11-11 23:14:31 [INFO] charm path in application "telegraf" does not exist: /home/ballot/charms/buildstelegraf.charm
2020-11-11 23:14:31 [ERROR] {'default_alias': 'zaza-5567d93822fa'}
2020-11-11 23:14:31 [ERROR] Model default_alias (zaza-5567d93822fa)
2020-11-11 23:14:31 [WARNING] unknown delta type: id
Traceback (most recent call last):
  File "/home/ballot/repos/charms/charm-k8s-telegraf/.tox/functional/bin/functest-run-suite", line 8, in <module>
    sys.exit(main())
  File "/home/ballot/repos/charms/charm-k8s-telegraf/.tox/functional/lib/python3.8/site-packages/zaza/charm_lifecycle/func_test_runner.py", line 259, in main
    func_test_runner(
  File "/home/ballot/repos/charms/charm-k8s-telegraf/.tox/functional/lib/python3.8/site-packages/zaza/charm_lifecycle/func_test_runner.py", line 200, in func_test_runner
    run_env_deployment(env_deployment, keep_model=preserve_model,
  File "/home/ballot/repos/charms/charm-k8s-telegraf/.tox/functional/lib/python3.8/site-packages/zaza/charm_lifecycle/func_test_runner.py", line 116, in run_env_deployment
    deploy.deploy(
  File "/home/ballot/repos/charms/charm-k8s-telegraf/.tox/functional/lib/python3.8/site-packages/zaza/charm_lifecycle/deploy.py", line 364, in deploy
    deploy_bundle(bundle, model, model_ctxt=model_ctxt, force=force)
  File "/home/ballot/repos/charms/charm-k8s-telegraf/.tox/functional/lib/python3.8/site-packages/zaza/charm_lifecycle/deploy.py", line 345, in deploy_bundle
    utils.check_output_logging(cmd)
  File "/home/ballot/repos/charms/charm-k8s-telegraf/.tox/functional/lib/python3.8/site-packages/zaza/charm_lifecycle/utils.py", line 443, in check_output_logging
    raise subprocess.CalledProcessError(return_code, cmd)
subprocess.CalledProcessError: Command '['juju', 'deploy', '-m', 'zaza-5567d93822fa', './tests/bundles/base.yaml', '--overlay', '/tmp/tmp5z33c9e1/local-charm-overlay.yaml']' returned non-zero exit status 1.
ERROR: InvocationError for command /home/ballot/repos/charms/charm-k8s-telegraf/.tox/functional/bin/functest-run-suite (exited with code 1)
_____________________________________________________________________________________________________ summary _____________________________________________________________________________________________________
ERROR:   functional: commands failed
make: *** [Makefile:32: functional] Error 1