Convert date to a known format

[j0k3r]

Instead of just validating the date is ok when parsing it, just convert it to the W3C format

[jtojnar]

Why not just make validateDate return ?DateTime?

[j0k3r]

@jtojnar because it'll break compatibility with current date return. Today we return a plain text which is a valid date according to parse_date function. Now it'll return a formatted date instead but it'll still be a string.

[coveralls]

Coverage increased (+0.005%) to 96.52% when pulling d1dbce1 on feature/convert-date into 497f073 on master.

[tcitworld]

DateTimeInterface ? Available since PHP 7.2 ? Looks odd.

[j0k3r]

Nope, it's only the constant that are moved to DateTimeInterface in PHP 7.2, before they were defined in DateTime:

7.2.0 | The class constants of DateTime are now defined on DateTimeInterface.