public function testPreserveInstance()
{
$conf = new ConfigurationFixture();
$conf->preserveInstance = true;
$conf->setOption('test1', 'val1');
$newConf = $conf->option('non-transient', 'val2');
$this->assertTrue($newConf->hasOption('test1'));
$this->assertTrue($newConf->hasOption('non-transient'));
$this->assertEquals('val1', $newConf->getOption('test1'));
$this->assertEquals('val2', $newConf->getOption('non-transient'));
$this->assertTrue($conf->hasOption('test1'));
$this->assertTrue($conf->hasOption('non-transient'));
$this->assertEquals('val1', $conf->getOption('test1'));
$this->assertEquals('val2', $conf->getOption('non-transient'));
$this->assertEquals($newConf, $conf);
$conf = new ConfigurationFixture();
$conf->preserveInstance = true;
$conf->merge(['test3' => 'val3', 'test4' => 'val4']);
$this->assertTrue($conf->hasOption('test3'));
$this->assertTrue($conf->hasOption('test4'));
$this->assertEquals('val3', $conf->getOption('test3'));
$conf->discard('test4');
$this->assertFalse($conf->hasOption('test4'));
$conf->push('values', 1, 2, 3);
$this->assertEquals([1, 2, 3], $conf->getOption('values'));
}