Use MySQL 5.7 for tests

JSON support is required for the tests to run, and this support was
added in MySQL 5.7, however only MySQL 5.6 is available at present on
Travis-CI.

Author: paultcochrane

.travis.yml

@@ -6,11 +6,24 @@ perl:
 matrix:
     include:
         - perl: "5.24"
-          env: COVERAGE=1
+          env: COVERAGE=1 MYSQL_VERSION=5.7
     allow_failures:
         - perl: "blead"
+          env: MYSQL_VERSION=5.7
 
 before_install:
+    - if [ x"$MYSQL_VERSION" != "x" ];
+      then
+        sudo service mysql stop;
+        sudo aptitude purge -y mysql-server libmysqlclient-dev mysql-server-5.6 mysql-common-5.6 mysql-client-5.6 libmysqlclient18 mysql-client-core-5.6 mysql-server-core-5.6 libdbd-mysql-perl mysql-common;
+        sudo apt-key adv --keyserver pgp.mit.edu --recv-keys 5072E1F5;
+        . /etc/lsb-release;
+        sudo add-apt-repository "deb http://repo.mysql.com/apt/ubuntu/ $DISTRIB_CODENAME mysql-$MYSQL_VERSION";
+        sudo apt-get update;
+        sudo DEBIAN_FRONTEND=noninteractive apt-get -q --yes --fix-broken --allow-unauthenticated --option DPkg::Options::=--force-confnew install mysql-server libmysqlclient-dev;
+        sudo mysql_upgrade -u root --password='' --force;
+        sudo service mysql restart;
+      fi
     - git clone git://github.com/travis-perl/helpers ~/travis-perl-helpers
     - source ~/travis-perl-helpers/init
     - build-perl