Update travis settings (#581)

* Add master branch and release tags to safelist
* Update build matrix: don't install python3.5 if running acceptance tests

.travis.yml

@@ -1,19 +1,28 @@
 sudo: true
 dist: trusty
 language: python
-python:
-- "3.5"  # 2.7 and 3.6 are preinstalled by default
 env:
   global:
   - ETCDVERSION=3.0.17 ZKVERSION=3.4.11 CONSULVERSION=0.7.4
   - PYVERSIONS="2.7 3.5 3.6"
+  - EXCLUDE_BEHAVE="3.5"
   - BOTO_CONFIG=/doesnotexist
-  matrix:
-  - TEST_SUITE="python setup.py"
-  - DCS="etcd" TEST_SUITE="behave"
-  - DCS="exhibitor" TEST_SUITE="behave"
-  - DCS="consul" TEST_SUITE="behave"
-  - DCS="kubernetes" TEST_SUITE="behave"
+matrix:
+  include:
+  - python: "3.5"
+    env: TEST_SUITE="python setup.py"
+  - python: "3.6"
+    env: DCS="etcd" TEST_SUITE="behave"
+  - python: "3.6"
+    env: DCS="exhibitor" TEST_SUITE="behave"
+  - python: "3.6"
+    env: DCS="consul" TEST_SUITE="behave"
+  - python: "3.6"
+    env: DCS="kubernetes" TEST_SUITE="behave"
+branches:
+  only:
+  - master
+  - /^v\d+\.\d+(\.\d+)?$/
 cache:
   directories:
   - $HOME/mycache
@@ -21,7 +30,7 @@ before_cache:
 - |
   rm -fr $HOME/mycache/python*
   for pv in $PYVERSIONS; do
-      if [[ $TEST_SUITE != "behave" || $pv != "3.5" ]]; then
+      if [[ $TEST_SUITE != "behave" || $pv != $EXCLUDE_BEHAVE ]]; then
           fpv=$(basename $(readlink $HOME/virtualenv/python${pv}))
           mv $HOME/virtualenv/${fpv} $HOME/mycache/${fpv}
       fi
@@ -98,7 +107,7 @@ install:
     fi
 
     for pv in $PYVERSIONS; do
-        if [[ $TEST_SUITE != "behave" || $pv != "3.5" ]]; then
+        if [[ $TEST_SUITE != "behave" || $pv != $EXCLUDE_BEHAVE ]]; then
             fpv=$(basename $(readlink $HOME/virtualenv/python$pv))
             if [[ -d ~/mycache/${fpv} ]]; then
                 mv ~/virtualenv/${fpv} ~/virtualenv/${fpv}.bckp
@@ -114,13 +123,17 @@ install:
 script:
   - |
     for pv in $PYVERSIONS; do
+        if [[ $TEST_SUITE == "behave" && $pv == $EXCLUDE_BEHAVE ]]; then
+            continue
+        fi
+
         source ~/virtualenv/python${pv}/bin/activate
 
         if [[ $TEST_SUITE != "behave" ]]; then
             echo Running unit tests using python${pv}
             $TEST_SUITE test
             $TEST_SUITE flake8
-        elif [[ $pv != "3.5" ]]; then
+        elif [[ $pv != $EXCLUDE_BEHAVE ]]; then
             echo Running acceptance tests using python${pv}
             if ! PATH=.:/usr/lib/postgresql/9.6/bin:$PATH $TEST_SUITE; then
                 # output all log files when tests are failing