Add MySQL 5.7 to Travis configuration

Following the same setup of doctrine/dbal#2764.

.travis.yml

@@ -18,6 +18,7 @@ before_script:
   - composer install --prefer-source
   - if [ "$DEPENDENCIES" != "low" ]; then composer update; fi;
   - if [ "$DEPENDENCIES" == "low" ]; then composer update --prefer-lowest; fi;
+  - if [ "$MYSQL_VERSION" == "5.7" ]; then bash ./tests/travis/install-mysql-5.7.sh; fi;
   - if [[ $DB == "mysql" || $DB == "mariadb" ]]; then mysql -e "CREATE SCHEMA doctrine_tests; GRANT ALL PRIVILEGES ON doctrine_tests.* to travis@'%'"; fi;
 
 script:
@@ -40,6 +41,13 @@ matrix:
         - DB=sqlite
         - DEPENDENCIES='low'
 
+    - php: 7.1
+      env: DB=mysql MYSQL_VERSION=5.7
+      sudo: required
+    - php: nightly
+      env: DB=mysql MYSQL_VERSION=5.7
+      sudo: required
+
   allow_failures:
     - php: nightly
 

tests/travis/install-mysql-5.7.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+set -ex
+
+echo "Installing MySQL 5.7..."
+
+sudo service mysql stop
+sudo apt-get remove "^mysql.*"
+sudo apt-get autoremove
+sudo apt-get autoclean
+echo mysql-apt-config mysql-apt-config/select-server select mysql-5.7 | sudo debconf-set-selections
+wget http://dev.mysql.com/get/mysql-apt-config_0.8.6-1_all.deb
+sudo DEBIAN_FRONTEND=noninteractive dpkg -i mysql-apt-config_0.8.6-1_all.deb
+sudo rm -rf /var/lib/apt/lists/*
+sudo apt-get clean
+sudo apt-get update -q
+sudo apt-get install -q -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" mysql-server libmysqlclient-dev
+sudo mysql_upgrade
+
+echo "Restart mysql..."
+sudo mysql -e "use mysql; update user set authentication_string=PASSWORD('') where User='root'; update user set plugin='mysql_native_password';FLUSH PRIVILEGES;"
+