Add linters check

This patch adds linters check with help of ansible-lint tool

Change-Id: Id7d11416ac7cf375211f9b9fb9c5bf2028cba496

.zuul.yaml

@@ -8,6 +8,8 @@
     check:
       jobs:
         - ffrouting-deploy
+        - tox-linters
     gate:
       jobs:
         - ffrouting-deploy
+        - tox-linters

test-requirements.txt

@@ -0,0 +1 @@
+ansible-lint

tests/test.yml

@@ -29,6 +29,7 @@
       shell: |
         set -e
         ping -c2 "{{ item.address }}"
+      changed_when: false
       register: _ping_vlan
       until: _ping_vlan is success
       retries: 5

tests/test_vars.yml

@@ -14,7 +14,7 @@
 # limitations under the License.
 
 frr_vlans:
-  - vlan-raw-device: eth0
+  - vlan-raw-device: "{{ ansible_default_ipv4.interface }}"
     id: 100
     address: 192.168.1.100
     netmask: 255.255.255.0

tox.ini

@@ -0,0 +1,36 @@
+[tox]
+minversion = 3.1
+skipsdist = True
+envlist = linters
+ignore_basepython_conflict = True
+
+[testenv]
+basepython = python3
+usedevelop = False
+commands =
+    /usr/bin/find . -type f -name "*.pyc" -delete
+deps =
+    -r{toxinidir}/test-requirements.txt
+passenv =
+    COMMON_TESTS_PATH
+    HOME
+    http_proxy
+    HTTP_PROXY
+    https_proxy
+    HTTPS_PROXY
+    no_proxy
+    NO_PROXY
+    TESTING_BRANCH
+    TESTING_HOME
+    USER
+whitelist_externals =
+    bash
+setenv =
+    PYTHONUNBUFFERED=1
+    TEST_IDEMPOTENCE=false
+    VIRTUAL_ENV={envdir}
+    WORKING_DIR={toxinidir}
+
+[testenv:linters]
+commands =
+    ansible-lint {toxinidir}/tests/test.yml