phpunit 6 update

.travis.yml

@@ -15,6 +15,9 @@ cache:
 
 env:
   global:
+    - COMPOSER_ARGS="--no-interaction"
+    - COVERAGE_DEPS="satooshi/php-coveralls"
+    - LEGACY_DEPS="phpunit/phpunit"
     - SITE_URL: https://zendframework.github.io/zend-mvc
     - GH_USER_NAME: "Matthew Weier O'Phinney"
     - GH_USER_EMAIL: matthew@weierophinney.net
@@ -58,10 +61,6 @@ matrix:
   allow_failures:
     - php: hhvm
 
-env:
-  global:
-    - COMPOSER_ARGS="--no-interaction --ignore-platform-reqs"
-
 notifications:
   irc: "irc.freenode.org#zftalk.dev"
   email: false
@@ -71,11 +70,12 @@ before_install:
   - if [[ $TRAVIS_PHP_VERSION != "hhvm" && $TEST_COVERAGE != 'true' ]]; then phpenv config-rm xdebug.ini ; fi
 
 install:
+  - travis_retry composer install $COMPOSER_ARGS
+  - if [[ $TRAVIS_PHP_VERSION =~ ^5.6 ]]; then travis_retry composer update $COMPOSER_ARGS --with-dependencies $LEGACY_DEPS ; fi
   - if [[ $DEPS == 'latest' ]]; then travis_retry composer update $COMPOSER_ARGS ; fi
   - if [[ $DEPS == 'lowest' ]]; then travis_retry composer update --prefer-lowest --prefer-stable $COMPOSER_ARGS ; fi
-  - if [[ $TEST_COVERAGE == 'true' ]]; then travis_retry composer require --dev $COMPOSER_ARGS satooshi/php-coveralls:^1.0 ; fi
-  - travis_retry composer install $COMPOSER_ARGS
-  - composer show --installed
+  - if [[ $TEST_COVERAGE == 'true' ]]; then travis_retry composer require --dev $COMPOSER_ARGS $COVERAGE_DEPS ; fi
+  - composer show
 
 script:
   - if [[ $TEST_COVERAGE == 'true' ]]; then composer test-coverage ; else composer test ; fi

composer.json

@@ -27,7 +27,7 @@
         "zendframework/zend-json": "^2.6.1 || ^3.0",
         "zendframework/zend-psr7bridge": "^0.2",
         "fabpot/php-cs-fixer": "1.7.*",
-        "phpunit/phpunit": "^4.5"
+        "phpunit/phpunit": "^6.0.7 || ^5.7.14"
     },
     "suggest": {
         "zendframework/zend-json": "(^2.6.1 || ^3.0) To auto-deserialize JSON body content in AbstractRestfulController extensions, when json_decode is unavailable",