diff --git a/.github/workflows/tests_with_mysql.yml b/.github/workflows/tests_with_mysql.yml
index 5ce7506..5c0a8e4 100644
--- a/.github/workflows/tests_with_mysql.yml
+++ b/.github/workflows/tests_with_mysql.yml
@@ -24,7 +24,8 @@ jobs:
           MYSQL_USER: root
           MYSQL_PASSWORD: 'BestPasswordEver'
         ports:
-          - 33306:3306
+          # will assign a random free host port
+          - 3306/tcp
         options: >-
           --health-cmd="mysqladmin ping"
           --health-interval=10s
@@ -34,7 +35,7 @@ jobs:
     steps:
       - name: Verify MySQL connection from host
         run: |
-          mysql --host 127.0.0.1 --port 33306 -uroot -pBestPasswordEver -e "SHOW DATABASES"
+          mysql --host 127.0.0.1 --port ${{ job.services.mysql.ports[3306] }} -uroot -pBestPasswordEver -e "SHOW DATABASES"
 
       - name: Checkout Redmine
         uses: actions/checkout@v2
@@ -82,6 +83,7 @@ jobs:
       - name: Run Redmine rake tasks
         env:
           RAILS_ENV: test
+          MYSQL_PORT: ${{ job.services.mysql.ports[3306] }}
         working-directory: redmine
         run: |
           bundle exec rake generate_secret_token
@@ -91,13 +93,13 @@ jobs:
       - name: Run tests
         env:
           RAILS_ENV: test
-          REDMINE_VERSION: ${{ matrix.redmine }}
+          MYSQL_PORT: ${{ job.services.mysql.ports[3306] }}
         working-directory: redmine
         run: bundle exec rake redmine:plugins:test NAME=redmine_messenger RUBYOPT="-W0"
 
       - name: Run uninstall test
         env:
           RAILS_ENV: test
-          REDMINE_VERSION: ${{ matrix.redmine }}
+          MYSQL_PORT: ${{ job.services.mysql.ports[3306] }}
         working-directory: redmine
         run: bundle exec rake redmine:plugins:migrate NAME=redmine_messenger VERSION=0
diff --git a/test/support/database-mysql.yml b/test/support/database-mysql.yml
index 9c60485..5e649ae 100644
--- a/test/support/database-mysql.yml
+++ b/test/support/database-mysql.yml
@@ -1,26 +1,8 @@
-production:
-  adapter: mysql2
-  database: redmine
-  host: 127.0.0.1
-  port: 33306
-  username: root
-  password: BestPasswordEver
-  encoding: utf8mb4
-
-development:
-  adapter: mysql2
-  database: redmine
-  port: 33306
-  host: 127.0.0.1
-  username: root
-  password: BestPasswordEver
-  encoding: utf8mb4
-
 test:
   adapter: mysql2
   database: redmine
-  port: 33306
+  port: <%= ENV["MYSQL_PORT"] %>
   host: 127.0.0.1
   username: root
-  password: BestPasswordEver
+  password:
   encoding: utf8mb4