public function testflatMapAssoc()
    {
        $array = array(
            'a' => array(
                '1' => array('.' => 0, ',' => 0),
                '2' => array('.' => 0, ',' => 0),
            ),
            'b' => array(
                '1' => array('.' => 0, ',' => 0),
                '2' => array('.' => 0, ',' => 0),
            ),
        );

        $keysList = array();
        $valuesList = array();
        Arrays::flatMapAssoc($array, function ($value, $keys) use (&$keysList, &$valuesList) {
            $keysList[] = $keys;
            $valuesList[] = $value;
        });

        $expectedKeysList = array(
            array('a', '1', '.'),
            array('a', '1', ','),
            array('a', '2', '.'),
            array('a', '2', ','),
            array('b', '1', '.'),
            array('b', '1', ','),
            array('b', '2', '.'),
            array('b', '2', ','),
        );
        $this->assertEquals($expectedKeysList, $keysList);
        $this->assertEquals(array_fill(0, 8, 0), $valuesList);
    }



    /**
     * @param array $array
     * @param callable $callback
     * @return array
     */
    public static function flatMapAssoc($array, $callback)
    {
        $callback = callback($callback);
        $walker = function ($array, $keys = array()) use (&$walker, $callback) {
            foreach ($array as $key => $value) {
                $currentKeys = $keys + array(count($keys) => $key);
                if (is_array($value)) {
                    $walker($value, $currentKeys);
                    continue;
                }
                $callback($value, $currentKeys);
            }
        };

        $walker($array);
    }