Use the official Oracle MySQL 5.6 / MySQL 5.7 server version in Circle CI with Environment Variables (or any other fork).

circle.yml

machine:
  environment:
    # JVM options
    _JAVA_OPTIONS: "-Xms512m -Xmx2048m -XX:MaxMetaspaceSize=256M"
    TERM: dumb
  java:
     version: openjdk8

dependencies:
  pre:
    # Remove the old version
    - sudo apt-get remove --purge mysql*
    - sudo rm -r /var/lib/mysql
    - sudo rm -r /var/log/mysql 
    - sudo rm -r /etc/mysql
    # Obtain the key for the MySQL Ubuntu repository here: http://pgp.mit.edu/pks/lookup?op=vindex&search=0x8C718D3B5072E1F5
    - sudo apt-key adv --keyserver ha.pool.sks-keyservers.net --recv-keys 5072E1F5   
    - sudo bash -c "echo \"deb http://repo.mysql.com/apt/ubuntu/ trusty mysql-5.6\" | tee -a /etc/apt/sources.list.d/mysql.list"          
    - sudo apt-get update
    # Empty password
    - echo "mysql-server mysql-server/root_password password ''" | sudo debconf-set-selections
    - echo "mysql-server mysql-server/root_password_again password ''" | sudo debconf-set-selections
    - DEBIAN_FRONTEND=noninteractive sudo apt-get install -y mysql-server
    # Setup default database user and privs
    # The variables are set in the settings page from the build on Circle CI
    - echo "CREATE USER '${SPRING_DATASOURCE_USERNAME}'@'localhost'" | mysql -u root
    - echo "GRANT ALL PRIVILEGES ON *.* TO '${SPRING_DATASOURCE_USERNAME}'@'localhost' WITH GRANT OPTION" | mysql -u root
    - echo "CREATE USER 'circle'@'localhost'" | mysql -u root
    - echo "GRANT ALL PRIVILEGES ON *.* TO 'circle'@'localhost' WITH GRANT OPTION" | mysql -u root
    - echo "FLUSH PRIVILEGES" | mysql -u root
    - echo "CREATE DATABASE circle_test" | mysql -u root

      
  override:
    - ./gradlew -q dependencies

database:
  override:
    - mysql -u ubuntu < ./src/test/resources/schema.sql

test:
  override:
    - ./gradlew test
  post:
    # copy the junit report files to the test report dir
    - mkdir -p $CIRCLE_TEST_REPORTS/junit/
    - find . -type f -regex ".*build/test-results/TEST-.*.xml" -exec cp {} $CIRCLE_TEST_REPORTS/junit/ \;