testing: enforce use of internal inventory

Avoids case where user system config could change outcome of testing.

Adds "driver_error" marker to molecule scenarios that have drivers that
did not pass our checks.

This avoids case where some pytest-molecule tests are skipped
accidentally.

Author: ssbarnea

tests/hosts.ini

@@ -0,0 +1 @@
+localhost ansible_connection=local

tox.ini

@@ -28,7 +28,8 @@ commands =
     pytest --color=yes --html={envlogdir}/reports.html --self-contained-html {tty:-s} --molecule-unavailable-driver= -k foo
 setenv =
     ANSIBLE_FORCE_COLOR={env:ANSIBLE_FORCE_COLOR:1}
-    ANSIBLE_INVENTORY={env:ANSIBLE_INVENTORY:{toxinidir}/../zuul-infra/inventory.yml}
+    # ANSIBLE_INVENTORY={env:ANSIBLE_INVENTORY:{toxinidir}/../zuul-infra/inventory.yml}
+    ANSIBLE_INVENTORY={env:ANSIBLE_INVENTORY:{toxinidir}/tests/hosts.ini}
     ANSIBLE_CONFIG={toxinidir}/ansible.cfg
     ANSIBLE_NOCOWS=1
     ANSIBLE_RETRY_FILES_ENABLED=0
@@ -64,7 +65,7 @@ commands =
       --source \
       --binary \
       --out-dir {toxinidir}/dist/ {toxinidir}
-    pytest --color=yes --html={envlogdir}/reports.html --self-contained-html {tty:-s} tests/roles/ensure-ansible
+    pytest --color=yes --html={envlogdir}/reports.html --self-contained-html {tty:-s} --molecule-unavailable-driver=driver_error tests/roles/ensure-ansible
 
 [testenv:devel]
 description: Unit testing using master branch of molecule