Period class next and previous methods when applied to quarter interval return different interval than expected

[Andon Totev]

Issue summary

Period class next and previous methods when applied to quarter interval return different interval than expected.

System informations

Information	Description
League\Period version	3.3.0
PHP/HHVM version	7.0.22
OS Platform	Linux

Standalone code, or other way to reproduce the problem

<?php

require_once 'vendor/autoload.php';

use League\Period\Period;

$qPrevious = Period::createFromQuarter(2014, 4);
$qCurrent  = Period::createFromQuarter(2015, 1);
$qNext     = Period::createFromQuarter(2015, 2);

var_dump($qCurrent->sameValueAs($qPrevious->next()));
var_dump($qCurrent->sameValueAs($qNext->previous()));

Expected result

boolean true
boolean true

Actual result

boolean false
boolean false

[ignace nyamagana butera]

@andont This is expected and documented behavior. Please refer to how Period::previous and Period::next work.