Add MySQL tests to Travis config

.travis.yml

@@ -7,14 +7,26 @@ php:
   - 7.4
   - 8.0
 
+services:
+  - mysql
+
+cache:
+  directories:
+    - $HOME/.composer/cache
+    - $HOME/vendor
+
+before_install:
+  - mysql -e 'CREATE DATABASE 2fauth_test;'
+
 before_script:
   - travis_retry composer self-update
-  - travis_retry composer install --no-interaction
+  - travis_retry composer install --no-interaction --prefer-source
   # no need to use a dedicated Travis .env file as phpunit
   # will use .env.testing by default
 
 script:
-  - vendor/bin/phpunit --coverage-clover=coverage.xml
+  - DATABASE=mysql vendor/bin/phpunit -c phpunit-mysql.xml
+  - DATABASE=sqlite vendor/bin/phpunit -c phpunit.xml  --coverage-clover=coverage.xml
 
 after_success:
 # Submit coverage report to https://codecov.io

phpunit-mysql.xml

@@ -32,10 +32,10 @@
         <env name="APP_ENV" value="testing"/>
         <!-- following values override .env.testing vars -->
         <env name="DB_CONNECTION" value="mysql"/>
-        <env name="DB_HOST" value="localhost"/>
+        <env name="DB_HOST" value="127.0.0.1"/>
         <env name="DB_PORT" value="3306"/>
         <env name="DB_DATABASE" value="2fauth_test"/>
-        <env name="DB_USERNAME" value="test_user"/>
+        <env name="DB_USERNAME" value="travis"/>
-        <env name="DB_PASSWORD" value="password"/>
+        <env name="DB_PASSWORD" value=""/>
     </php>
 </phpunit>