using new .travis.yml config as suggested by @weaverryan

.travis.yml

@@ -1,36 +1,38 @@
 language: php
-
 sudo: false
-
 cache:
     directories:
         - $HOME/.composer/cache/files
+        - $HOME/symfony-bridge/.phpunit
 
-php:
-    - 7.1
-    - 7.2
-    - 7.3
+env:
+    global:
+        - PHPUNIT_FLAGS="-v"
+        - SYMFONY_PHPUNIT_DIR="$HOME/symfony-bridge/.phpunit"
+        - SYMFONY_REQUIRE='>=2.8'
 
 matrix:
     fast_finish: true
     include:
-        # test the latest release (including beta releases)
         - php: 7.1
-          env: deps=beta
         - php: 7.2
-          env: deps=beta
         - php: 7.3
-          env: deps=beta
+          env: deps=low
 
 before_install:
-    - if [ "$deps" = 'beta' ]; then perl -pi -e 's/^}$/,"minimum-stability":"beta"}/' composer.json; fi;
-    - if [ "$deps" = 'dev' ]; then perl -pi -e 's/^}$/,"minimum-stability":"dev"}/' composer.json; fi;
+    - phpenv config-rm xdebug.ini || true
+    - composer global require --no-progress --no-scripts --no-plugins symfony/flex dev-master
 
 install:
-    - composer update $COMPOSER_FLAGS
+    - |
+        if [[ $deps = low ]]; then
+            export SYMFONY_DEPRECATIONS_HELPER=weak
+            composer update --prefer-dist --prefer-lowest --prefer-stable
+        else
+            composer update --prefer-dist
+        fi
+    - ./vendor/bin/simple-phpunit install
 
-script: phpunit --coverage-text
-
-notifications:
-    email:
-        - travis@knplabs.com
+script:
+    - composer validate --strict --no-check-lock
+    - ./vendor/bin/simple-phpunit $PHPUNIT_FLAGS