Better CI with PHP 8 tests

Author: thomasvargiu

.travis.yml

@@ -1,23 +1,37 @@
 language: php
 
-dist: trusty
+cache:
+  directories:
+    - $HOME/.composer/cache
 
-php:
-  - 7.3
-  - 7.4
+env:
+  global:
+    - COMPOSER_ARGS="--no-interaction"
 
 matrix:
+  fast_finish: true
   include:
+    - php: 7.3
+      env: dependencies=lowest
     - php: 7.3
       env: dependencies=highest
+    - php: 7.4
+      env: dependencies=lowest
     - php: 7.4
       env: dependencies=highest
+    - php: 8.0
+      env:
+        - dependencies=lowest
+        - COMPOSER_ARGS="--no-interaction --ignore-platform-reqs"
+    - php: 8.0
+      env:
+        - dependencies=highest
+        - COMPOSER_ARGS="--no-interaction --ignore-platform-reqs"
 
 before_script:
-  - composer self-update
-  - if [ -z "$dependencies" ]; then composer install --prefer-dist -n; fi;
-  - if [ "$dependencies" = "lowest" ]; then composer update --prefer-dist --prefer-lowest -n; fi;
-  - if [ "$dependencies" = "highest" ]; then composer require laminas/laminas-mvc-console:^1.1 --prefer-dist -n; fi;
+  - travis_retry composer install $COMPOSER_ARGS --ignore-platform-reqs
+  - if [[ "$dependencies" == "lowest" ]]; then travis_retry composer update --prefer-dist --prefer-lowest --prefer-stable $COMPOSER_ARGS; fi;
+  - if [[ "$dependencies" == "highest" ]]; then travis_retry composer require laminas/laminas-mvc-console:^1.1 --prefer-dist $COMPOSER_ARGS; fi;
 
 script:
   - ./vendor/bin/phpunit