Improved Travis testing configuration

.travis.yml

@@ -21,49 +21,44 @@ env:
 matrix:
   fast_finish: true
   include:
+    # bleeding edge (unreleased dev versions where failures are allowed)
     - php: nightly
       env: SYMFONY_VERSION="dev-master"
+    # stable (most recent stable versions)
     - php: 7.1
       env:
         - SYMFONY_VERSION="3.2.*"
         - TWIG_VERSION="2.x-dev"
         - CHECK_PHP_SYNTAX="yes"
+    # common (some popular version combinations)
     - php: 7.0
       env: SYMFONY_VERSION="3.1.*"
-    - php: 5.6
-      env: SYMFONY_VERSION="2.3.*"
-    - php: 5.6
-      env: SYMFONY_VERSION="2.7.*"
+    # common (some popular version combinations)
     - php: 5.6
       env:
         - SYMFONY_VERSION="2.8.*"
         - ENABLE_CODE_COVERAGE="true"
+    # legacy (oldest supported versions)
     - php: 5.3
       env:
         - SYMFONY_VERSION="2.3.*"
         - COMPOSER_FLAGS="--prefer-lowest"
-    - php: hhvm-stable
-      env: SYMFONY_VERSION="2.8.*"
-      sudo: required
-      dist: trusty
-      group: edge
   allow_failures:
     - php: nightly
-    - php: hhvm-stable
-    - env: TWIG_VERSION="2.x-dev"
+    # code coverage is very slow; allow a failure to get the Travis result early
     - env:
         - SYMFONY_VERSION="2.8.*"
         - ENABLE_CODE_COVERAGE="true"
 
 before_install:
   - stty cols 120
-  - if [[ ! $TRAVIS_PHP_VERSION = hhvm* ]]; then INI_FILE=~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/travis.ini; else INI_FILE=/etc/hhvm/php.ini; fi
+  - INI_FILE=~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/travis.ini
   - echo memory_limit = -1 >> $INI_FILE
   - echo session.gc_probability = 0 >> $INI_FILE
   - echo opcache.enable_cli = 1 >> $INI_FILE
   - if [[ "SYMFONY_VERSION" == "2.8.*" || "SYMFONY_VERSION" == 3.* ]]; then export SYMFONY_DEPRECATIONS_HELPER="strict"; fi;
   - if [[ "$ENABLE_CODE_COVERAGE" != "true" ]]; then rm -f ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/xdebug.ini; fi;
-  - composer selfupdate
+  - composer self-update
   - if [[ "$SYMFONY_VERSION" != "" ]]; then composer require "symfony/symfony:${SYMFONY_VERSION}" --no-update; fi;
   - if [[ "$TWIG_VERSION" != "" ]]; then composer require "twig/twig:${TWIG_VERSION}" --no-update; fi;