/**
  * @covers SortArray::usort
  * @group  stablesort
  */
 public function testAssociation()
 {
     $source = array('a' => array('red', 3), 'b' => array('green', 2), 'c' => array('blue', 2), 'd' => array('yellow', 1));
     $expected = array(0 => array('yellow', 1), 1 => array('green', 2), 2 => array('blue', 2), 3 => array('red', 3));
     $array = $source;
     SortArray::usort($array, array(__CLASS__, 'compare_integer'));
     $this->assertSame($expected, $array);
 }