test: Use TEST_JUJU_CHANNEL pass from Makefile to control juju version

Makefile

@@ -77,19 +77,19 @@ unittests:
 
 functional: build
 	@echo "Executing functional tests using built charm at ${PROJECTPATH}"
-	@CHARM_LOCATION=${PROJECTPATH} tox -e func -- ${FUNC_ARGS}
+	@TEST_JUJU_CHANNEL=2.9/stable CHARM_LOCATION=${PROJECTPATH} tox -e func -- ${FUNC_ARGS}
 
 functional31: build
 	@echo "Executing functional tests using built charm at ${PROJECTPATH} with juju 3.1 requirements"
-	@CHARM_LOCATION=${PROJECTPATH} tox -e func31 -- ${FUNC_ARGS}
+	@TEST_JUJU_CHANNEL=3.1/stable CHARM_LOCATION=${PROJECTPATH} tox -e func -- ${FUNC_ARGS}
 
 functional32: build
 	@echo "Executing functional tests using built charm at ${PROJECTPATH} with juju 3.2 requirements"
-	@CHARM_LOCATION=${PROJECTPATH} tox -e func32 -- ${FUNC_ARGS}
+	@TEST_JUJU_CHANNEL=3.2/stable CHARM_LOCATION=${PROJECTPATH} tox -e func -- ${FUNC_ARGS}
 
 functional33: build
 	@echo "Executing functional tests using built charm at ${PROJECTPATH} with juju 3.3 requirements"
-	@CHARM_LOCATION=${PROJECTPATH} tox -e func33 -- ${FUNC_ARGS}
+	@TEST_JUJU_CHANNEL=3.3/stable CHARM_LOCATION=${PROJECTPATH} tox -e func -- ${FUNC_ARGS}
 
 test: lint unittests functional
 	@echo "Tests completed for charm ${CHARM_NAME}."

tox.ini

@@ -25,6 +25,7 @@ passenv =
   SNAP_HTTP_PROXY
   SNAP_HTTPS_PROXY
   OS_*
+  TEST_*
 
 [testenv:dev-environment]
 envdir = {toxinidir}/.venv
@@ -77,40 +78,15 @@ deps =
     pytest-cov
 
 [testenv:func]
-setenv =
-  TEST_JUJU_CHANNEL = 2.9/stable
 changedir = {toxinidir}/tests/functional
 commands = functest-run-suite {posargs:--keep-faulty-model}
 deps =
   git+https://github.com/openstack-charmers/zaza.git#egg=zaza
   -r {toxinidir}/tests/functional/requirements.txt
 
-[testenv:func31]
-setenv =
-  TEST_JUJU_CHANNEL = 3.1/stable
-changedir = {toxinidir}/tests/functional
-commands =
-  functest-run-suite {posargs:--keep-faulty-model}
-deps =
-  git+https://github.com/openstack-charmers/[email protected]#egg=zaza
-  -r {toxinidir}/tests/functional/requirements.txt
-
-[testenv:func32]
-setenv =
-  TEST_JUJU_CHANNEL = 3.2/stable
-changedir = {toxinidir}/tests/functional
-commands =
-  functest-run-suite {posargs:--keep-faulty-model}
-deps =
-  git+https://github.com/openstack-charmers/[email protected]#egg=zaza
-  -r {toxinidir}/tests/functional/requirements.txt
-
-[testenv:func33]
-setenv =
-  TEST_JUJU_CHANNEL = 3.3/stable
+[testenv:func3]
 changedir = {toxinidir}/tests/functional
-commands =
-  functest-run-suite {posargs:--keep-faulty-model}
+commands = functest-run-suite {posargs:--keep-faulty-model}
 deps =
   git+https://github.com/openstack-charmers/[email protected]#egg=zaza
   -r {toxinidir}/tests/functional/requirements.txt