public function testFoldLeftRight()
{
$map = new Map(array('a' => 'b', 'c' => 'd', 'e' => 'f'));
$rsLeft = $map->foldLeft('', function ($a, $b) {
return $a . $b;
});
$rsRight = $map->foldRight('', function ($a, $b) {
return $a . $b;
});
$this->assertEquals('bdf', $rsLeft);
$this->assertEquals('bdf', $rsRight);
}
