public function testJoin()
{
$input = array('ąćęł', 'foo', 'bar', 123);
$expected = 'ąćęłfoobar123';
$this->assertEquals($expected, Arr::join($input));
$expected = 'ąćęł+foo+bar+123';
$this->assertEquals($expected, Arr::join($input, '+'));
}
