Description:
------------
---
From manual page: http://www.php.net/dateinterval.format#refsect1-
dateinterval.format-description
---
Code:
echo date_diff(date_create('1970-00-00 00:00:00'), date_create())->format('%s');

Expected Output:
- A big number (at least 1372823738)

Current Output:
- A number less than 60

The value of the output should add up to the smaller date in date diff to 
produce the larger date. Or at least approximately. Since I am only including s 
in the format, the reported value for s should be exactly equal to the Unix 
timestamp.

Test script:
---------------
echo date_diff(date_create('1970-00-00 00:00:00'), date_create())->format('%s');

Expected result:
----------------
A big number (at least 1372823738)

Actual result:
--------------
A number less than 60