iCalendar Reader: Resolve inconsistent use of unixtime and $current

Adds the filter `ical_get_current_time` to the initial call to `time()` to allow unit tests to run from a set unixtime.

Updates `date()` and `time()` functions running with the default timestamp `time()` to include this value as the second parameter, ensuring that the entirety of `filter_past_and_recurring_events()` runs from the same value for `$current`.

Merges r112068-wpcom.

Author: jmdodd

_inc/lib/icalendar-reader.php

@@ -87,7 +87,7 @@ public function get_events( $url = '', $count = 5 ) {
 	protected function filter_past_and_recurring_events( $events ) {
 		$upcoming = array();
 		$set_recurring_events = array();
-		$current = time();
+		$current = apply_filters( 'ical_get_current_time', time() );
 
 		foreach ( $events as $event ) {
 
@@ -140,7 +140,7 @@ protected function filter_past_and_recurring_events( $events ) {
 							}
 						} else {
 							$echo_limit = 10;
-							$current_date = date( 'Ymd' );
+							$current_date = date( 'Ymd', $current );
 							if ( 8 == strlen( $event['DTSTART'] ) ) {
 								$recurring_event_date_start = $current_date;
 								$recurring_event_date_end = $current_date;
@@ -164,7 +164,7 @@ protected function filter_past_and_recurring_events( $events ) {
 							}
 						} else {
 							$echo_limit = 3;
-							$current_date = date( 'Ym' );
+							$current_date = date( 'Ym', $current );
 							if ( 8 == strlen( $event['DTSTART'] ) ) {
 								$recurring_event_date_start = date( "d", strtotime( $event['DTSTART'] ) );
 								$recurring_event_date_end = date( "d", strtotime( $event['DTEND'] ) );
@@ -192,7 +192,7 @@ protected function filter_past_and_recurring_events( $events ) {
 							}
 						} else {
 							$echo_limit = 2;
-							$current_date = date( 'Ym' );
+							$current_date = date( 'Ym', $current );
 							if ( 8 == strlen( $event['DTSTART'] ) ) {
 								$recurring_event_date_start = date( "d", strtotime( $event['DTSTART'] ) );
 								$recurring_event_date_end = date( "d", strtotime( $event['DTEND'] ) );
@@ -216,7 +216,7 @@ protected function filter_past_and_recurring_events( $events ) {
 							}
 						} else {
 							$echo_limit = 1;
-							$current_date = date( 'Y' );
+							$current_date = date( 'Y', $current );
 							if ( 8 == strlen( $event['DTSTART'] ) ) {
 								$recurring_event_date_start = date( "md", strtotime( $event['DTSTART'] ) );
 								$recurring_event_date_end = date( "md", strtotime( $event['DTEND'] ) );
@@ -254,7 +254,7 @@ protected function filter_past_and_recurring_events( $events ) {
 						}
 						$event_start = strtotime( $recurring_event_date_start );
 						$event_end = strtotime( $recurring_event_date_end );
-						$until = ( isset( $rrule_array['UNTIL'] ) ) ? strtotime( $rrule_array['UNTIL'] ) : strtotime( '+1 year' );
+						$until = ( isset( $rrule_array['UNTIL'] ) ) ? strtotime( $rrule_array['UNTIL'] ) : strtotime( '+1 year', $current );
 						$exdate = ( isset( $event['EXDATE;VALUE=DATE'] ) ) ? $event['EXDATE;VALUE=DATE'] : null;
 
 						if ( isset( $rrule_array['BYDAY'] ) && $frequency === 'week' ) {