Symfony 4 Compatibility

.gitattributes

@@ -0,0 +1,5 @@
+/Tests export-ignore
+/phpunit.xml.dist export-ignore
+/.gitattributes export-ignore
+/.gitignore export-ignore
+/Resources/doc export-ignore

.travis.yml

@@ -2,36 +2,57 @@ sudo: false
 
 language: php
 
-php:
-    - 5.5
-    - 5.6
-    - 7.0
-    - 7.1
-    - 7.2
-    - hhvm
-
 cache:
     directories:
         - $HOME/.composer/cache/files
 
-env:
-    - SYMFONY_VERSION="^3.0.2"
-    - SYMFONY_VERSION="^3.0.2" COMPOSER_FLAGS="--prefer-lowest"
-
-matrix:
+jobs:
     fast_finish: true
+    include:
+        - php: 7.1.33
+          env:
+            - SYMFONY_VERSION="^3.4.0"
+
+        - php: 7.1.33
+          env:
+            - SYMFONY_VERSION="4.0.*"
+
+        - php: 7.1.33
+          env:
+            - SYMFONY_VERSION="4.0.*" COMPOSER_FLAGS="--prefer-lowest"
+
+        - php: 7.3
+          env:
+            - SYMFONY_VERSION="^4.3"
+
+        - php: 7.3
+          env:
+            - SYMFONY_VERSION="^4.4"
+
+        - php: 7.3
+          env:
+            - SYMFONY_VERSION="^5.0"
+
+        - php: 7.3
+          env:
+            - SYMFONY_VERSION="dev"
 
     allow_failures:
-        - php: 7.2
-        - php: hhvm
+        - php: 7.3
+          env: SYMFONY_VERSION="dev"
+
+        - php: 7.3
+          env: SYMFONY_VERSION="^5.0"
 
 before_install:
-    - phpenv config-rm xdebug.ini
     - composer self-update
     - if [ "${SYMFONY_VERSION}" != "" ]; then composer require --no-update "symfony/symfony:${SYMFONY_VERSION}"; fi;
+    - if [[ $COVERAGE != true ]]; then phpenv config-rm xdebug.ini || true; fi
+    - if ! [ -z "$STABILITY" ]; then composer config minimum-stability ${STABILITY}; fi;
+    - if ! [ -v "$DEPENDENCIES" ]; then composer require --no-update ${DEPENDENCIES}; fi;
 
 install:
-    - composer update ${COMPOSER_FLAGS} --prefer-source
+    - composer update ${COMPOSER_FLAGS} --prefer-dist --no-interaction  --prefer-stable
 
 script:
     - vendor/bin/phpunit --colors