notifications: Introduce Notification Middleware and NotificationEnvelope

To allow ourselves esier processing/modifying Notifications lets
introduce an idea of NotificationsEnvelope which represents a
Notification being sent and list of recipients.

The middleware approach will allow us to modify the Notification
behaviour by letting extensions to inject/modify the Notifications.

Each Middleware will retrieve a list of Envelopes MediaWiki wants to
send. Middlewares should iterate over envelopes and decide if those
want to add/remove/replace Notifications and/or Recipients.

Bug: T387996
Change-Id: Ib3ee35c75b2f4dcfdc516b9259a852dc73c4a778

1 files changed, 94 insertions, 0 deletions

diff --git a/tests/phpunit/unit/includes/Notification/NotificationBatchTest.php b/tests/phpunit/unit/includes/Notification/NotificationBatchTest.php
new file mode 100644
index 000000000000..4cda67741215
--- /dev/null
+++ b/tests/phpunit/unit/includes/Notification/NotificationBatchTest.php
@@ -0,0 +1,94 @@
+<?php
+
+namespace MediaWiki\Tests\Notification;
+
+use MediaWiki\Notification\Notification;
+use MediaWiki\Notification\NotificationEnvelope;
+use MediaWiki\Notification\NotificationsBatch;
+use MediaWiki\Notification\RecipientSet;
+use MediaWikiUnitTestCase;
+use stdClass;
+
+/**
+ * @covers \MediaWiki\Notification\NotificationsBatch
+ * @covers \MediaWiki\Notification\NotificationEnvelope
+ */
+class NotificationBatchTest extends MediaWikiUnitTestCase {
+
+	public function testAdds() {
+		$first = new NotificationEnvelope( new Notification( 'first' ), new RecipientSet( [] ) );
+		$second = new NotificationEnvelope( new Notification( 'second' ), new RecipientSet( [] ) );
+
+		$batch = new NotificationsBatch( $first );
+		$batch->add( $second );
+
+		$this->assertCount( 2, $batch );
+		$envelopesArray = iterator_to_array( $batch );
+		$this->assertSame( $first, $envelopesArray[0] );
+		$this->assertSame( $second, $envelopesArray[1] );
+	}
+
+	public function testRemoveWhenExists() {
+		$first = new NotificationEnvelope( new Notification( 'first' ), new RecipientSet( [] ) );
+		$second = new NotificationEnvelope( new Notification( 'second' ), new RecipientSet( [] ) );
+		$third = new NotificationEnvelope( new Notification( 'third' ), new RecipientSet( [] ) );
+		$last = new NotificationEnvelope( new Notification( 'fourth' ), new RecipientSet( [] ) );
+
+		$batch = new NotificationsBatch( $first, $second, $third, $last );
+		$this->assertCount( 4, $batch );
+
+		$batch->remove( $second );
+		$this->assertCount( 3, $batch );
+		$envelopesArray = iterator_to_array( $batch );
+		$this->assertSame( $first, $envelopesArray[0] );
+		$this->assertSame( $third, $envelopesArray[1] );
+		$this->assertSame( $last, $envelopesArray[2] );
+
+		$batch->remove( $first );
+		$this->assertCount( 2, $batch );
+		$envelopesArray = iterator_to_array( $batch );
+		$this->assertSame( $third, $envelopesArray[0] );
+		$this->assertSame( $last, $envelopesArray[1] );
+
+		$batch->remove( $last );
+		$this->assertCount( 1, $batch );
+		$envelopesArray = iterator_to_array( $batch );
+		$this->assertSame( $third, $envelopesArray[0] );
+	}
+
+	public function testRemovesWhenNotExists() {
+		$first = new NotificationEnvelope( new Notification( 'first' ), new RecipientSet( [] ) );
+		$second = new NotificationEnvelope( new Notification( 'second' ), new RecipientSet( [] ) );
+		$other = new NotificationEnvelope( new Notification( 'third' ), new RecipientSet( [] ) );
+
+		$batch = new NotificationsBatch( $first, $second );
+		$batch->remove( $other );
+
+		$this->assertCount( 2, $batch );
+		$envelopesArray = iterator_to_array( $batch );
+		$this->assertSame( $first, $envelopesArray[0] );
+		$this->assertSame( $second, $envelopesArray[1] );
+	}
+
+	public function testFilters() {
+		$first = new NotificationEnvelope( new Notification( 'first' ), new RecipientSet( [] ) );
+		$second = new NotificationEnvelope( new Notification( 'second' ), new RecipientSet( [] ) );
+
+		$filterMock = $this->getMockBuilder( stdClass::class )
+			->addMethods( [ '__invoke' ] )
+			->getMock();
+
+		$filterMock->expects( $this->exactly( 2 ) )
+			->method( '__invoke' )
+			->willReturnCallback( static function ( NotificationEnvelope $envelope ) use ( $first ) {
+				return $envelope->equals( $first );
+			} );
+
+		$batch = new NotificationsBatch( $first, $second );
+		$batch->filter( $filterMock );
+		$this->assertCount( 1, $batch );
+		$envelopesArray = iterator_to_array( $batch );
+		$this->assertSame( $first, $envelopesArray[0] );
+	}
+
+}