make test.sh configurable and add comments

Test/test.sh

@@ -1,15 +1,23 @@
 #!/usr/bin/env sh
-
-phpdismod xdebug;
-
+# start mysql database service
 service mysql start
-
+# create default database and user from cake2-app-template:/Config/.env.default
 mysql -h localhost -u root -e "CREATE DATABASE database_name;CREATE DATABASE test_database_name;CREATE USER 'user'@'localhost' IDENTIFIED BY 'password';GRANT ALL PRIVILEGES ON * . * TO 'user'@'localhost';"
-
+# use this repository symlinked into the app template
 composer config repositories.cakephp-filter-plugin '{"type": "path", "url": "/cakephp-filter-plugin", "options": {"symlink": true}}'
+# prevent composer from looking up packages on packagist.org
 composer config repo.packagist false
+# require the current dev version of the filter plugin
 composer require --prefer-source kba-team/cakephp-filter-plugin:@dev
-vendor/bin/phpunit Plugin/Filter/Test/Case/Controller/Component/FilterComponentTest.php
-E=$?
+# Either use the test case from the parameter, or run all tests
+if [ -n "${1}" ]; then
+    # call PHPUnit and remember return code
+    vendor/bin/phpunit "Plugin/Filter/${1}"
+    E=$?
+else
+    (>&2 echo "ERROR: Missing test case!")
+fi
+# stop mysql service at the end of the tests
 service mysql stop
+# exit with the return code of phpunit
 exit $E