composer require --dev lucasbustamante/db-dumper-for-codeception

Add the command to your codeception.yml:

extensions:
    commands:
        - DumpGenerator\GenerateDump

On a suite that uses a Codeception\Modules\Db module (or any module that extends Db), add these parameters:

modules:
    config:
        Db:
            dump_dsn: 'mysql:host=%DUMP_DB_HOST%;dbname=%DUMP_DB_NAME%'
            dump_user: '%DUMP_DB_USER%'
            dump_password: '%DUMP_DB_PASSWORD%'

Replace %DUMP_DB_HOST% and similars with your actual values. This should be your local development database, from which the dumps will be generated from.

Run ./vendor/bin/codecept dump <suite>

In the first run, a Dump config file will be generated at tests/data/<dump>.sql.php where you can fine-tune how your dump will be generated. On the subsequent runs, it will generate the dump based on the config. If you don't override any config, it will just do a full dump of the database.

This library is basically a Codeception wrapper around https://packagist.org/packages/ifsnop/mysqldump-php.

You can check their documentation to get more information on how exactly you can fine-tune your dump.