README

A PSR-20 Clock implementation.

Interface

This is the only method provided by the PSR-20 Clock interface.

<?php

namespace Psr\Clock;

interface ClockInterface
{
    /**
     * Returns the current time as a DateTimeImmutable Object
     */
    public function now(): \DateTimeImmutable;

}

Interoperability with DateTime Libraries

Today, Carbon and Chronos are known as useful libraries that extend the DateTime class.

Both provide classes that extend from DateTimeImmutable, so it's easy to get an adapter.

• CarbonClock
• ChronosClock

If the PSR defines the Clock interface, it is convenient for these adapters to be shipped with their respective libraries for the user.

DateTime for Testing

Writing tests for time-dependent functions is hard. Clock Interface is one of the solutions for that.

However, this requires the application to remove the new DateTime() (no arguments) and the time functions (date(), time(), strtotime()).

Other options are php-timecop, Chronos::setTestNow(), Carbon::setTestNow() and rashidlaasri/travel. However, they are not object-oriented as they depend on global state (or static properties).

Testing helper classes

• FixedClock
• ProgressingFixedClock