function _testRemove($extension)
{
$writer = File_Archive::toArchive("test.{$extension}", File_Archive::toVariable($x));
$writer->newFile('foo.txt');
$writer->writeData('ABCDEF');
$writer->newFile('bla_to_remove.txt');
$writer->writeData('GHIJKL');
$writer->newFile('bar.txt');
$writer->writeData('MNOP');
$writer->close();
File_Archive::removeFromSource(File_Archive::predEreg('_to_remove'), $source = File_Archive::readSource(File_Archive::readMemory($x, "test.{$extension}"), "test.{$extension}/"));
$this->assertEquals("foo.txt\nbar.txt", implode("\n", $source->getFileList()));
}