REVIEW: add unit tests agains 5.7

.gitlab-ci.yml

@@ -62,8 +62,8 @@ unittests-mariadb:
   script:
     - make pipeline-test SQL_HOST=mariadb
 
-# Run the unit tests with MySQL
-unittests-mysql:
+# Run the unit tests with MySQL 8
+unittests-mysql-8
   tags: [ docker ]
   stage: test
   # Should not stop the pipeline from continuing.
@@ -75,6 +75,19 @@ unittests-mysql:
   script:
     - make pipeline-test SQL_HOST=mysql
 
+# Run the unit tests with MySQL 5
+unittests-mysql-5
+  tags: [ docker ]
+  stage: test
+  # Should not stop the pipeline from continuing.
+  allow_failure: true
+  services:
+    - name: mysql:5.7
+      command: ["--default-authentication-plugin=mysql_native_password"]
+
+  script:
+    - make pipeline-test SQL_HOST=mysql
+
 ######## Deploy ########
 
 # Trigger building of server image and integration tests