For testing purposes I have to create a copy of a production MySQL database that cannot be touched.

These are the steps I would follow:

1. Create a reduced size database backup:

   mysqldump prodDB --single-transaction --where="true limit 20" > test.sql

2. Create a new test database: testDB

3. Load the dump file in the new test database:

   mysql testDB < test.sql

Is this procedure correct?
Can I be sure that the original database will not be modified whatsoever?

Thank you!

System: MySQL 5.1 with InnoDB