PHPUnit_Framework_TestCase memory leak with large DataProvider - symfony

Question

When I run PHPUnit, it appears to me as if it had a memory-leak when running many tests inside a single test class. But I don't know if this is a bug or it was the expected behaviour.
To reproduce:
I create a simple testHello() with a silly assertTrue(true).
I feed it from providerHello(). Just feeding 3 dummy params.
With $numberOfTests = 1;, consumed memory is 5.75MB.
PHPUnit output = Time: 0 seconds, Memory: 5.75Mb
With $numberOfTests = 10000;, I don't expect the memory to grow so much, just the size of the new array. But the used memory is 99.75MB which I feel it is too much.
PHPUnit output = Time: 4 seconds, Memory: 99.75Mb
I added a dirty echo() in the provider, just to know how much memory the array made the script to consume.
With 1 test: Memory = 5294552 (5.2MB)
With 10.000 tests: Memory = 15735352 (15.7MB)
The questions:
Why do I loose 84MB in the way? (99.75 really consumed - 15.75 really used by the array)
Is it hormal that it allocates memory at each iteration, probably its internal setUp(), but does not free the same amount at the internal tearDown()?
Am I doing anything wrong?
My version:
phpunit --version gives PHPUnit 3.6.10 by Sebastian Bergmann..
This is the code:
<?php
class DemoTest extends \PHPUnit_Framework_TestCase
{
/** #dataProvider providerHello */
public function testHello( $a, $b, $c )
{
$this->assertTrue( true );
}
public function providerHello()
{
$numberOfTests = 10000;
$data = array();
for( $i = 0; $i < $numberOfTests; $i++ )
{
$data[] = array( 1, 2, 3 );
}
echo( "Memory = " . memory_get_peak_usage() . PHP_EOL );
return $data;
}
}
?>

Answer 1

you need to set backupGlobals and backupStaticAttributes to false in your phpunit.xml file. If you don't use an config file you can also do so on the command line.
--no-globals-backup
--static-backup