Question

I would like to know whether the setting null to variables in the tearDown methods within PHPUnit_Framework_TestCase and children is a mere formality or serves some actual purpose.

Example:

protected function tearDown(){
  $this->someUsedVariable=null;
}

P.S.: I mean, don’t used variables get destroyed anyway by the end of the script?

Answer 1

Of course they are destroyed at the end of the script. Once you started your test suite your script does not end directly, because you’ll probably have hundrets or thousands of test cases being executed and all those test cases together will sooner or later use up all memory / fill up the max. number of connections to a database (etc.) if not properly teared down.

By setting variables to null you allow the garbage collector, once activated, to free up the used memory.