Explain Composer and PHPUnit exceptions

Author: tfrommen

.travis.yml

@@ -34,16 +34,20 @@ jobs:
     - language: php
       php: 8.0
       install:
+        # For PHP 8.0+, we need to ignore platform reqs as PHPUnit 7 is still used.
         - composer install --ignore-platform-reqs
       script:
         - vendor/bin/phpunit
     - language: php
       php: 8.1
       install:
+        # For PHP 8.0+, we need to ignore platform reqs as PHPUnit 7 is still used.
         - composer install --ignore-platform-reqs
       script:
-        - vendor/bin/phpunit --no-configuration --bootstrap=tests/bootstrap.php tests/FixtureTests.php
+        # For PHP 8.1+, we need to ignore the config file so that PHPUnit 7 doesn't try to read it and cause an error.
+        # Instead, we pass all required settings as part of the phpunit command.
         - vendor/bin/phpunit --no-configuration --bootstrap=tests/bootstrap.php tests/AllSniffs.php
+        - vendor/bin/phpunit --no-configuration --bootstrap=tests/bootstrap.php tests/FixtureTests.php
     - language: node_js
       node_js: 10
       install: