PHP: Test cases for getting timestamp one month later to now

// Test cases for http://stackoverflow.com/questions/10834350/php-date-functions-results-related-to-the-next-month-are-not-correct-php-bugs
// http://i.imgur.com/KwlJq.png

[1]. Timestamp to test ($timestamp_to_test) (string):
'2012-06-01 03:31:48'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2012-07-01 03:31:48'

[2]. Timestamp to test ($timestamp_to_test) (string):
'2011-01-28 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2011-02-28 23:59:59'

[3]. Timestamp to test ($timestamp_to_test) (string):
'2011-01-29 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2011-02-28 23:59:59'

[4]. Timestamp to test ($timestamp_to_test) (string):
'2011-01-30 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2011-02-28 23:59:59'

[5]. Timestamp to test ($timestamp_to_test) (string):
'2011-01-31 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2011-02-28 23:59:59'

[6]. Timestamp to test ($timestamp_to_test) (string):
'2012-01-28 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2012-02-28 23:59:59'

[7]. Timestamp to test ($timestamp_to_test) (string):
'2012-01-29 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2012-02-29 23:59:59'

[8]. Timestamp to test ($timestamp_to_test) (string):
'2012-01-30 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2012-02-29 23:59:59'

[9]. Timestamp to test ($timestamp_to_test) (string):
'2012-01-31 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2012-02-29 23:59:59'

[10]. Timestamp to test ($timestamp_to_test) (string):
'2012-02-29 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2012-03-29 23:59:59'

[11]. Timestamp to test ($timestamp_to_test) (string):
'2012-03-30 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2012-04-30 23:59:59'

[12]. Timestamp to test ($timestamp_to_test) (string):
'2012-03-31 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2012-04-30 23:59:59'

[13]. Timestamp to test ($timestamp_to_test) (string):
'2012-04-30 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2012-05-30 23:59:59'

[14]. Timestamp to test ($timestamp_to_test) (string):
'2012-05-31 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2012-06-30 23:59:59'

[15]. Timestamp to test ($timestamp_to_test) (string):
'2012-12-31 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2013-01-31 23:59:59'

[16]. Timestamp to test ($timestamp_to_test) (string):
'2013-01-31 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2013-02-28 23:59:59'

[17]. Timestamp to test ($timestamp_to_test) (string):
'2013-02-28 23:59:59'

Timestamp + 1 month (getOneMonthLaterTimestamp($timestamp_to_test)) (string):
'2013-03-28 23:59:59'