VSzA techblog

When I created registr, I wanted a way to test it on the same RDBMS as the one I use for Redmine, MySQL. For the purposes of testing, I wanted to start a fresh instance of mysqld that could be ran without superuser privileges, without affecting other running MySQL instances, and with minimal resource consumtion.

Although the test suite was developed in Python, the idea can be used with any language that makes it possible to create temporary directories in a manner that avoids race conditions and spawn processes. The code can be found in the TestRedmineMySQL class, and it follows the steps described below.

• Create a temporary directory (path)
• Create a directory inside path (datadir)
• Generate two filenames inside path (socket and pidfile)
• Spawn the mysqld_safe binary with the following parameters.
  • --socket= and the value of socket makes MySQL accept connections throught that file
  • --datadir= and the value of datadir makes MySQL store all databases in that directory
  • --skip-networking disables the TCP listener, thus minimizes interference with other instances
  • --skip_grant_tables disables access control, since we don't need that for testing
  • --pid-file= and the value of pidfile makes MySQL store the process ID in that file
• Do what you want with the database
• Open the file named pidfile and read an integer from the only row
• Send a SIGTERM to the PID
• Wait for the process to finish.

The above way worked fine for me, didn't leave any garbage on the system, and ran as fast as an Oracle product could do. :)