[Tests] improvements:

 - `node` `v7`/`v4.6`; drop `v5`
 - re-enable karma builds, but allow them to fail
 - correct before_script settings for karma tests
 - install appropriate react version, per `$REACT`
 - Ensure tests aren’t ran twice

.travis.yml

 language: node_js
 node_js:
+  - "7"
   - "6"
-  - "5"
   - "4"
-  - "4.2"
+  - "4.6"
   - "iojs"
 before_script:
-  - 'if [ "${TRAVIS_NODE_VERSION}" = 6 ]; then export DISPLAY=:99.0; fi'
-  - 'if [ "${TRAVIS_NODE_VERSION}" = 6 ]; then sh -e /etc/init.d/xvfb start; fi'
-  - 'if [ "${TRAVIS_NODE_VERSION}" = 6 ]; then sleep 3; fi'
+  - 'if [ -n "${KARMA-}" ]; then export DISPLAY=:99.0; fi'
+  - 'if [ -n "${KARMA-}" ]; then sh -e /etc/init.d/xvfb start; fi'
+  - 'if [ -n "${KARMA-}" ]; then sleep 3; fi'
+  - 'if [ -n "${REACT-}" ] && [ -n "${TEST-}" ]; then sh install-relevant-react.sh; fi'
 script:
   - 'if [ -n "${LINT-}" ]; then npm run lint ; fi'
   - 'if [ -n "${TEST-}" ]; then npm run tests-only ; fi'
   - 'if [ -n "${KARMA-}" ]; then npm run tests-karma ; fi'
-  - 'if [ -n "${REACT-}" ]; then npm run tests-only; fi'
 after_success:
   - 'if [ "${TRAVIS_NODE_VERSION}" = "4.2" ]; then npm run cover; cat ./coverage/lcov.info | ./node_modules/.bin/coveralls ; fi'
 env:
   global:
-    - REACT=0.14
-  matrix:
     - TEST=true
+  matrix:
+    - REACT=0.14
+    - REACT=15
 sudo: false
 matrix:
   fast_finish: true
   include:
-#    - node_js: "node"
-#      env: KARMA=true
+    - node_js: "node"
+      env: KARMA=true
     - node_js: "node"
       env: LINT=true
   allow_failures:
     - node_js: "iojs"
+    - env: KARMA=true

install-relevant-react.sh

+#!/bin/sh
+
+REACT=${REACT:-15}
+
+echo "installing React $REACT"
+
+if [ "$REACT" = "0.14" ]; then
+    npm run react:14
+fi
+
+if [ "$REACT" = "15" ]; then
+    npm run react:15
+fi

package.json

@@ -15,6 +15,9 @@
     "cover:mocha": "babel-node ./node_modules/istanbul/lib/cli cover node_modules/mocha/bin/_mocha -- --compilers js:babel-register,jsx:babel-register --require airbnb-js-shims --recursive ./test/_helpers test/**/*",
     "lint": "eslint --ext .js,.jsx src test",
     "mocha": "mocha --compilers js:babel-register,jsx:babel-register --require airbnb-js-shims --recursive ./test/_helpers",
+    "react:clean": "rimraf node_modules/react node_modules/react-dom node_modules/react-addons-test-utils",
+    "react:14": "rimraf node_modules/.bin/npm && npm run react:clean && npm i react@0.14 react-dom@0.14 react-addons-test-utils@0.14",
+    "react:15": "rimraf node_modules/.bin/npm && npm run react:clean && npm i react@15 react-dom@15 react-addons-test-utils@15",
     "pretest": "npm run --silent lint",
     "tests-only": "npm run mocha --silent test",
     "tests-karma": "karma start",