👷 Add old MySQL 5.5 to Travis CI again.

The trusty distro contains MySQL 5.6. Add a precise distro with MySQL 5.5.
Unfortunately 5.7 is not yet provided, which would be interesting
because of the enabled strict SQL mode.

.travis.yml

@@ -28,7 +28,7 @@ addons:
       - graphviz
       - ttf-liberation
 
-# enable and start databases?
+# enable and start databases on a per job basis
 #services:
 #  - mariadb
 #  - postgresql
@@ -52,7 +52,8 @@ env:
     - PHPUCOV: "--no-coverage"
   # use matrix only for PHP and MySQL, all other combinations added through includes
   matrix:
-    - DB=mysql
+    # trusty default MySQL 5.6
+    - DB=mysql MYSQL_VERSION=5.6
 
 # Matrix configuration details
 matrix:
@@ -73,7 +74,13 @@ matrix:
         postgresql: '9.6'
       services:
         - postgresql
-   # Exclude from default matrix combinations
+    # PHP7.1, old precise distribution with MySQL 5.5
+    - php: '7.1'
+      env: DB=mysql MYSQL_VERSION=5.5
+      dist: precise
+      services:
+        - mysql
+   # Excludes from default matrix combinations
 #  exclude:
 #    - php: hhvm
 #      env: DB=pgsql  # PDO driver for pgsql is unsupported by HHVM (3rd party install for support)

tests/phpunit-mysql.xml

@@ -6,7 +6,7 @@
          beStrictAboutOutputDuringTests="true"
          beStrictAboutTestsThatDoNotTestAnything="true"
          beStrictAboutTodoAnnotatedTests="true"
-         processIsolation="true"
+         processIsolation="false"
          verbose="true">
     <testsuite name="Hubzilla default Test Suite">
         <directory suffix="Test.php">./unit/</directory>

tests/travis/prepare_mysql.sh

@@ -31,6 +31,8 @@ echo "Preparing for MySQL ..."
 mysql --version
 mysql -e "SELECT VERSION();"
 mysql -e "SHOW VARIABLES LIKE 'max_allowed_packet';"
+mysql -e "SHOW VARIABLES LIKE 'collation_%';"
+mysql -e "SHOW VARIABLES LIKE 'character_set%';"
 mysql -e "SELECT @@sql_mode;"
 
 # Create Hubzilla database