public function testGetOpponents()
 {
     $conflict = new PackageConflict('token', array('package1', 'package2'));
     $this->assertSame(array('package2'), $conflict->getOpponents('package1'));
     $this->assertSame(array('package1'), $conflict->getOpponents('package2'));
     $this->assertSame(array(), $conflict->getOpponents('package3'));
 }