diff --git a/composer.json b/composer.json
index f38bc96..0f33ee4 100644
--- a/composer.json
+++ b/composer.json
@@ -61,7 +61,7 @@
         ],
         "test-debug": [
             "@prepare-test",
-            "@test-event-sources"
+            "@test-gatherpress"
         ],
         "test-vs-event-list": "phpunit --filter=vs_event_list",
         "test-the-events-calendar": "phpunit --filter=the_events_calendar",
diff --git a/includes/activitypub/transmogrifier/class-base.php b/includes/activitypub/transmogrifier/class-base.php
index 4b3f52a..517ae89 100644
--- a/includes/activitypub/transmogrifier/class-base.php
+++ b/includes/activitypub/transmogrifier/class-base.php
@@ -56,7 +56,7 @@ abstract class Base {
 		$post_id = $this->save_event();
 
 		if ( $post_id ) {
-			update_post_meta( $post_id, 'event_bridge_for_activitypub_is_cached', 'yes' );
+			update_post_meta( $post_id, '_event_bridge_for_activitypub_is_cached', true );
 			update_post_meta( $post_id, 'activitypub_content_visibility', constant( 'ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL' ) ?? '' );
 		}
 	}
diff --git a/includes/activitypub/transmogrifier/class-gatherpress.php b/includes/activitypub/transmogrifier/class-gatherpress.php
index 9420eb5..7567373 100644
--- a/includes/activitypub/transmogrifier/class-gatherpress.php
+++ b/includes/activitypub/transmogrifier/class-gatherpress.php
@@ -131,8 +131,8 @@ class GatherPress extends Base {
 		$args = array(
 			'post_title'   => sanitize_text_field( $this->activitypub_event->get_name() ),
 			'post_type'    => 'gatherpress_event',
-			'post_content' => wp_kses_post( $this->activitypub_event->get_content() ) . '<!-- wp:gatherpress/venue /-->',
-			'post_excerpt' => wp_kses_post( $this->activitypub_event->get_summary() ),
+			'post_content' => wp_kses_post( $this->activitypub_event->get_content() ?? '' ) . '<!-- wp:gatherpress/venue /-->',
+			'post_excerpt' => wp_kses_post( $this->activitypub_event->get_summary() ?? '' ),
 			'post_status'  => 'publish',
 			'guid'         => sanitize_url( $this->activitypub_event->get_id() ),
 		);
diff --git a/includes/class-event-sources.php b/includes/class-event-sources.php
index e4b12aa..7019d3f 100644
--- a/includes/class-event-sources.php
+++ b/includes/class-event-sources.php
@@ -71,7 +71,7 @@ class Event_Sources {
 			}
 			\register_post_meta(
 				$event_plugin_integration::get_post_type(),
-				'event_bridge_for_activitypub_is_cached',
+				'_event_bridge_for_activitypub_is_cached',
 				array(
 					'type'              => 'string',
 					'single'            => false,
@@ -159,7 +159,7 @@ class Event_Sources {
 	 * @return bool
 	 */
 	public static function is_cached_external_event_post( $post ): bool {
-		if ( get_post_meta( $post->ID, 'event_bridge_for_activitypub_is_cached', true ) ) {
+		if ( get_post_meta( $post->ID, '_event_bridge_for_activitypub_is_cached', true ) ) {
 			return true;
 		}
 
diff --git a/includes/integrations/class-gatherpress.php b/includes/integrations/class-gatherpress.php
index c54156d..87f5dae 100644
--- a/includes/integrations/class-gatherpress.php
+++ b/includes/integrations/class-gatherpress.php
@@ -116,7 +116,7 @@ final class GatherPress extends Event_Plugin_Integration implements Feature_Even
 				if ( $post && 'gatherpress_event' === $post->post_type ) {
 					// Add your custom logic here to decide whether to force the link.
 					// For example, force it only if a specific meta field exists.
-					if ( get_post_meta( $post->ID, 'event_bridge_for_activitypub_is_cached', true ) ) {
+					if ( get_post_meta( $post->ID, '_event_bridge_for_activitypub_is_cached', true ) ) {
 						return true; // Force the online event link.
 					}
 				}
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 35433bf..7ad614c 100755
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -6,9 +6,9 @@
  */
 
 // Defined here because setting them in .wp-env.json doesn't work for some reason.
-\define( 'WP_TESTS_DOMAIN', 'example.org' );
-\define( 'WP_SITEURL', 'http://example.org' );
-\define( 'WP_HOME', 'http://example.org' );
+\defined( 'WP_TESTS_DOMAIN' ) ?? \define( 'WP_TESTS_DOMAIN', 'example.org' );
+\defined( 'WP_SITEURL' ) ?? \define( 'WP_SITEURL', 'http://example.org' );
+\defined( 'WP_HOME' ) ?? \define( 'WP_HOME', 'http://example.org' );
 
 $_tests_dir = getenv( 'WP_TESTS_DIR' );
 
@@ -87,6 +87,9 @@ function _manually_load_plugin() {
 			break;
 		case 'gatherpress':
 			$plugin_file = 'gatherpress/gatherpress.php';
+			\update_option( 'event_bridge_for_activitypub_event_sources_active', true );
+			\update_option( 'event_bridge_for_activitypub_integration_used_for_event_sources_feature', \Event_Bridge_For_ActivityPub\Integrations\GatherPress::class );
+			\update_option( 'activitypub_actor_mode', ACTIVITYPUB_BLOG_MODE );
 			break;
 		case 'wp_event_manager':
 			$plugin_file = 'wp-event-manager/wp-event-manager.php';
@@ -105,7 +108,7 @@ function _manually_load_plugin() {
 		// For the Event Sources feature we currently only test with GatherPress.
 		_manually_load_event_plugin( 'gatherpress/gatherpress.php' );
 		\update_option( 'event_bridge_for_activitypub_event_sources_active', true );
-		\update_option( 'event_bridge_for_activitypub_plugin_used_for_event_source_feature', 'GatherPress' );
+		\update_option( 'event_bridge_for_activitypub_integration_used_for_event_sources_feature', 'GatherPress' );
 		\update_option( 'activitypub_actor_mode', ACTIVITYPUB_BLOG_MODE );
 	} else {
 		// For all other tests we mainly use the Events Calendar as a reference.
diff --git a/tests/includes/activitypub/transformer/class-test-event-organiser.php b/tests/includes/activitypub/transformer/class-test-event-organiser.php
index ecced27..fc5dee5 100644
--- a/tests/includes/activitypub/transformer/class-test-event-organiser.php
+++ b/tests/includes/activitypub/transformer/class-test-event-organiser.php
@@ -28,7 +28,7 @@ class Test_Event_Organiser extends \WP_UnitTestCase {
 		$aec->activate_activitypub_support_for_active_event_plugins();
 
 		// Run the install script just in time which makes sure the custom tables exist and more.
-		eventorganiser_install();
+		\eventorganiser_install();
 
 		// Delete all posts afterwards.
 		_delete_all_posts();
@@ -48,8 +48,8 @@ class Test_Event_Organiser extends \WP_UnitTestCase {
 		$this->assertContains( 'event', get_option( 'activitypub_support_post_types' ) );
 
 		$event_data = array(
-			'start'    => new DateTime( '+10 days 15:00:00', eo_get_blog_timezone() ),
-			'end'      => new DateTime( '+10 days 16:00:00', eo_get_blog_timezone() ),
+			'start'    => new DateTime( '+10 days 15:00:00', \eo_get_blog_timezone() ),
+			'end'      => new DateTime( '+10 days 16:00:00', \eo_get_blog_timezone() ),
 			'all_day'  => 0,
 			'schedule' => 'once',
 		);
@@ -60,7 +60,7 @@ class Test_Event_Organiser extends \WP_UnitTestCase {
 			'post_status'  => 'publish',
 		);
 
-		$post_id = eo_insert_event( $post_data, $event_data );
+		$post_id = \eo_insert_event( $post_data, $event_data );
 
 		// Call the transformer Factory.
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( get_post( $post_id ) );
@@ -87,7 +87,7 @@ class Test_Event_Organiser extends \WP_UnitTestCase {
 			'post_status'  => 'publish',
 		);
 
-		$post_id = eo_insert_event( $post_data, $event_data );
+		$post_id = \eo_insert_event( $post_data, $event_data );
 
 		// Call the transformer Factory.
 		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $post_id ) )->to_object()->to_array();
@@ -95,9 +95,9 @@ class Test_Event_Organiser extends \WP_UnitTestCase {
 		// Check that the event ActivityStreams representation contains everything as expected.
 		$this->assertEquals( 'Event', $event_array['type'] );
 		$this->assertEquals( 'Unit Test Event', $event_array['name'] );
-		$this->assertEquals( 'Unit Test description.', wp_strip_all_tags( $event_array['content'] ) );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( 'Unit Test description.', \wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
 		$this->assertEquals( 'external', $event_array['joinMode'] );
 		$this->assertArrayNotHasKey( 'location', $event_array );
 	}
@@ -118,7 +118,7 @@ class Test_Event_Organiser extends \WP_UnitTestCase {
 			'longitude'   => 15.421371,
 		);
 		$venue_name = 'Fediverse Venue';
-		$venue      = eo_insert_venue( $venue_name, $venue_args );
+		$venue      = \eo_insert_venue( $venue_name, $venue_args );
 
 		// Mock Event.
 		$event_data = array(
@@ -132,8 +132,8 @@ class Test_Event_Organiser extends \WP_UnitTestCase {
 			'post_content' => 'Unit Test description.',
 			'post_status'  => 'publish',
 		);
-		$post_id    = eo_insert_event( $post_data, $event_data );
-		wp_set_object_terms( $post_id, $venue['term_id'], 'event-venue' );
+		$post_id    = \eo_insert_event( $post_data, $event_data );
+		\wp_set_object_terms( $post_id, $venue['term_id'], 'event-venue' );
 
 		// Call the transformer Factory.
 		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $post_id ) )->to_object()->to_array();
@@ -141,12 +141,12 @@ class Test_Event_Organiser extends \WP_UnitTestCase {
 		// Check that the event ActivityStreams representation contains everything as expected.
 		$this->assertEquals( 'Event', $event_array['type'] );
 		$this->assertEquals( 'Unit Test Event', $event_array['name'] );
-		$this->assertEquals( 'Unit Test description.', wp_strip_all_tags( $event_array['content'] ) );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( 'Unit Test description.', \wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
 		$this->assertEquals( 'external', $event_array['joinMode'] );
 		$this->assertArrayHasKey( 'location', $event_array );
-		$this->assertEquals( $venue_args['description'], wp_strip_all_tags( $event_array['location']['content'] ) );
+		$this->assertEquals( $venue_args['description'], \wp_strip_all_tags( $event_array['location']['content'] ) );
 		$this->assertEquals( $venue_args['address'], $event_array['location']['address']['streetAddress'] );
 		$this->assertEquals( $venue_args['city'], $event_array['location']['address']['addressLocality'] );
 		$this->assertEquals( $venue_args['state'], $event_array['location']['address']['addressRegion'] );
diff --git a/tests/includes/activitypub/transformer/class-test-event.php b/tests/includes/activitypub/transformer/class-test-event.php
index ddabfe1..37e4d14 100644
--- a/tests/includes/activitypub/transformer/class-test-event.php
+++ b/tests/includes/activitypub/transformer/class-test-event.php
@@ -8,6 +8,8 @@
 
 namespace Event_Bridge_For_ActivityPup\Tests\ActivityPub\Transformer;
 
+use Event_Bridge_For_ActivityPup\Tests\ActivityPub\Transformer\Test_The_Events_Calendar;
+
 /**
  * Test class for Shortcodes.
  */
@@ -49,15 +51,15 @@ class Test_Event extends \WP_UnitTestCase {
 		$transformer->register_shortcodes();
 
 		$summary = '[ap_start_time]';
-		$summary = do_shortcode( $summary );
+		$summary = \do_shortcode( $summary );
 		$this->assertEquals( '🗓️ Start: December 1, 2024 3:00 pm', $summary );
 
 		$summary = '[ap_start_time icon="false"]';
-		$summary = do_shortcode( $summary );
+		$summary = \do_shortcode( $summary );
 		$this->assertEquals( 'Start: December 1, 2024 3:00 pm', $summary );
 
 		$summary = '[ap_start_time icon="false" label="false"]';
-		$summary = do_shortcode( $summary );
+		$summary = \do_shortcode( $summary );
 		$this->assertEquals( 'December 1, 2024 3:00 pm', $summary );
 
 		$transformer->unregister_shortcodes();
@@ -82,15 +84,15 @@ class Test_Event extends \WP_UnitTestCase {
 		$transformer->register_shortcodes();
 
 		$summary = '[ap_end_time]';
-		$summary = do_shortcode( $summary );
+		$summary = \do_shortcode( $summary );
 		$this->assertEquals( '⏳ End: December 1, 2024 4:00 pm', $summary );
 
 		$summary = '[ap_end_time icon="false"]';
-		$summary = do_shortcode( $summary );
+		$summary = \do_shortcode( $summary );
 		$this->assertEquals( 'End: December 1, 2024 4:00 pm', $summary );
 
 		$summary = '[ap_end_time icon="false" label="false"]';
-		$summary = do_shortcode( $summary );
+		$summary = \do_shortcode( $summary );
 		$this->assertEquals( 'December 1, 2024 4:00 pm', $summary );
 
 		$transformer->unregister_shortcodes();
diff --git a/tests/includes/activitypub/transformer/class-test-eventin.php b/tests/includes/activitypub/transformer/class-test-eventin.php
index fb1960f..019eb0e 100644
--- a/tests/includes/activitypub/transformer/class-test-eventin.php
+++ b/tests/includes/activitypub/transformer/class-test-eventin.php
@@ -56,7 +56,7 @@ class Test_Eventin extends \WP_UnitTestCase {
 		$this->assertEquals( 1, count( $active_event_plugins ) );
 
 		// Enable ActivityPub support for the event plugin.
-		$this->assertContains( 'etn', get_option( 'activitypub_support_post_types' ) );
+		$this->assertContains( 'etn', \get_option( 'activitypub_support_post_types' ) );
 
 		// Create a Eventin Event without content.
 		$event = new \Etn\Core\Event\Event_Model();
@@ -161,12 +161,12 @@ class Test_Eventin extends \WP_UnitTestCase {
 
 		$this->assertEquals( 'Event', $event_array['type'] );
 		$this->assertEquals( 'Eventin Test Event Title', $event_array['name'] );
-		$this->assertEquals( 'Eventin Test Event Description', wp_strip_all_tags( $event_array['content'] ) );
-		$this->assertEquals( gmdate( 'Y-m-d\TH:i:s\Z', strtotime( '+10 days 15:00:00' ) ), $event_array['startTime'] );
-		$this->assertEquals( gmdate( 'Y-m-d\TH:i:s\Z', strtotime( '+10 days 16:00:00' ) ), $event_array['endTime'] );
+		$this->assertEquals( 'Eventin Test Event Description', \wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( \gmdate( 'Y-m-d\TH:i:s\Z', \strtotime( '+10 days 15:00:00' ) ), $event_array['startTime'] );
+		$this->assertEquals( \gmdate( 'Y-m-d\TH:i:s\Z', \strtotime( '+10 days 16:00:00' ) ), $event_array['endTime'] );
 		$this->assertEquals( 'Europe/Vienna', $event_array['timezone'] );
-		$this->assertEquals( comments_open( $event->id ), $event_array['commentsEnabled'] );
-		$this->assertEquals( comments_open( $event->id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( \comments_open( $event->id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( \comments_open( $event->id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
 		$this->assertEquals( 'external', $event_array['joinMode'] );
 		$this->assertArrayHasKey( 'location', $event_array );
 		$this->assertEquals( 'MEETING', $event_array['category'] );
diff --git a/tests/includes/activitypub/transformer/class-test-events-manger.php b/tests/includes/activitypub/transformer/class-test-events-manger.php
index 9031f88..b5fb931 100644
--- a/tests/includes/activitypub/transformer/class-test-events-manger.php
+++ b/tests/includes/activitypub/transformer/class-test-events-manger.php
@@ -46,7 +46,7 @@ class Test_Events_Manager extends \WP_UnitTestCase {
 		$this->assertContains( EM_POST_TYPE_EVENT, get_option( 'activitypub_support_post_types' ) );
 
 		// Insert a new Event.
-		$wp_post_id = wp_insert_post(
+		$wp_post_id = \wp_insert_post(
 			array(
 				'post_title'  => 'Events Manager Test event',
 				'post_status' => 'publish',
@@ -57,7 +57,7 @@ class Test_Events_Manager extends \WP_UnitTestCase {
 			)
 		);
 
-		$wp_object = get_post( $wp_post_id );
+		$wp_object = \get_post( $wp_post_id );
 
 		// Call the transformer Factory.
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
@@ -102,7 +102,7 @@ class Test_Events_Manager extends \WP_UnitTestCase {
 	 */
 	public function test_transform_of__full_event_with_location() {
 		// Create a mockup location.
-		$location                    = new EM_Location();
+		$location                    = new \EM_Location();
 		$location->location_name     = 'Test location';
 		$location->location_address  = 'Test Address';
 		$location->location_town     = 'Test Town';
@@ -113,7 +113,7 @@ class Test_Events_Manager extends \WP_UnitTestCase {
 		$this->assertTrue( $location->save() );
 
 		// Create mockup event.
-		$event                   = new EM_Event();
+		$event                   = new \EM_Event();
 		$event->event_name       = 'Events Manager Test event';
 		$event->post_content     = 'Event description';
 		$event->location_id      = $location->location_id;
@@ -151,21 +151,21 @@ class Test_Events_Manager extends \WP_UnitTestCase {
 	 */
 	public function test_transform_of_event_with_name_only_location() {
 		// Create a mockup location.
-		$location                = new EM_Location();
+		$location                = new \EM_Location();
 		$location->location_name = 'Name only location';
 		$this->assertTrue( $location->save() );
 
 		// Create mockup event.
-		$event                   = new EM_Event();
+		$event                   = new \EM_Event();
 		$event->event_name       = 'Events Manager Test event';
 		$event->post_content     = 'Event description';
 		$event->location_id      = $location->location_id;
-		$event->event_start_date = gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) );
-		$event->event_end_date   = gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) );
+		$event->event_start_date = \gmdate( 'Y-m-d', \strtotime( '+10 days 15:00:00' ) );
+		$event->event_end_date   = \gmdate( 'Y-m-d', \strtotime( '+10 days 16:00:00' ) );
 		$event->event_start_time = '15:00:00';
 		$event->event_end_time   = '16:00:00';
-		$event->start            = strtotime( $event->event_start_date . ' ' . $event->event_start_time );
-		$event->end              = strtotime( $event->event_end_date . ' ' . $event->event_end_time );
+		$event->start            = \strtotime( $event->event_start_date . ' ' . $event->event_start_time );
+		$event->end              = \strtotime( $event->event_end_date . ' ' . $event->event_end_time );
 		$event->force_status     = 'publish';
 		$event->event_rsvp       = false;
 		$this->assertTrue( $event->save() );
@@ -177,7 +177,7 @@ class Test_Events_Manager extends \WP_UnitTestCase {
 		$this->assertEquals( 'Event', $event_array['type'] );
 		$this->assertEquals( 'Events Manager Test event', $event_array['name'] );
 		$this->assertEquals( 'Event description', wp_strip_all_tags( $event_array['content'] ) );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
 		$this->assertEquals( 'external', $event_array['joinMode'] );
 		$this->assertEquals( 'MEETING', $event_array['category'] );
 		$this->assertArrayHasKey( 'location', $event_array );
diff --git a/tests/includes/activitypub/transformer/class-test-gatherpress.php b/tests/includes/activitypub/transformer/class-test-gatherpress.php
index 58d70fb..a95058e 100644
--- a/tests/includes/activitypub/transformer/class-test-gatherpress.php
+++ b/tests/includes/activitypub/transformer/class-test-gatherpress.php
@@ -22,9 +22,9 @@ class Test_GatherPress extends \WP_UnitTestCase {
 		}
 
 		// Mock the plugin activation.
-		GatherPress\Core\Setup::get_instance()->activate_gatherpress_plugin( false );
+		\GatherPress\Core\Setup::get_instance()->activate_gatherpress_plugin( false );
 
-		// Make sure that ActivityPub support is enabled for The Events Calendar.
+		// Make sure that ActivityPub support is enabled for GatherPress.
 		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
 		$aec->activate_activitypub_support_for_active_event_plugins();
 
diff --git a/tests/includes/activitypub/transformer/class-test-modern-events-calendar-lite.php b/tests/includes/activitypub/transformer/class-test-modern-events-calendar-lite.php
index 35e3221..b58fe24 100644
--- a/tests/includes/activitypub/transformer/class-test-modern-events-calendar-lite.php
+++ b/tests/includes/activitypub/transformer/class-test-modern-events-calendar-lite.php
@@ -49,7 +49,7 @@ class Test_Modern_Events_Calendar_Lite extends \WP_UnitTestCase {
 		$this->assertEquals( 1, count( $active_event_plugins ) );
 
 		// Enable ActivityPub support for the event plugin.
-		$this->assertContains( 'mec-events', get_option( 'activitypub_support_post_types' ) );
+		$this->assertContains( 'mec-events', \get_option( 'activitypub_support_post_types' ) );
 
 		// Insert a new Event.
 		$event = array(
@@ -70,7 +70,7 @@ class Test_Modern_Events_Calendar_Lite extends \WP_UnitTestCase {
 
 		$post_id = $this->mec_main->save_event( $event );
 
-		$wp_object = get_post( $post_id );
+		$wp_object = \get_post( $post_id );
 
 		// Call the transformer Factory.
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
@@ -83,22 +83,22 @@ class Test_Modern_Events_Calendar_Lite extends \WP_UnitTestCase {
 	 * Test that the transformation of minimal event.
 	 */
 	public function test_modern_events_calendar_lite_minimal_event() {
-		$start_timestamp = strtotime( '+10 days 15:00:00' );
-		$end_timestamp   = strtotime( '+10 days 16:00:00' );
+		$start_timestamp = \strtotime( '+10 days 15:00:00' );
+		$end_timestamp   = \strtotime( '+10 days 16:00:00' );
 
 		// Insert a new Event.
 		$event = array(
 			'title'              => 'MEC Test Event',
 			'status'             => 'publish',
 			'content'            => 'This is the content of the MEC!',
-			'start_time_hour'    => gmdate( 'h', $start_timestamp ),
-			'start_time_minutes' => gmdate( 'i', $start_timestamp ),
-			'start_time_ampm'    => gmdate( 'A', $start_timestamp ),
-			'start'              => gmdate( 'Y-m-d', $start_timestamp ),
-			'end'                => gmdate( 'Y-m-d', $end_timestamp ),
-			'end_time_hour'      => gmdate( 'h', $end_timestamp ),
-			'end_time_minutes'   => gmdate( 'i', $end_timestamp ),
-			'end_time_ampm'      => gmdate( 'A', $end_timestamp ),
+			'start_time_hour'    => \gmdate( 'h', $start_timestamp ),
+			'start_time_minutes' => \gmdate( 'i', $start_timestamp ),
+			'start_time_ampm'    => \gmdate( 'A', $start_timestamp ),
+			'start'              => \gmdate( 'Y-m-d', $start_timestamp ),
+			'end'                => \gmdate( 'Y-m-d', $end_timestamp ),
+			'end_time_hour'      => \gmdate( 'h', $end_timestamp ),
+			'end_time_minutes'   => \gmdate( 'i', $end_timestamp ),
+			'end_time_ampm'      => \gmdate( 'A', $end_timestamp ),
 			'repeat_status'      => 0,
 			'repeat_type'        => 'daily',
 			'interval'           => 1,
@@ -106,16 +106,16 @@ class Test_Modern_Events_Calendar_Lite extends \WP_UnitTestCase {
 
 		$post_id = $this->mec_main->save_event( $event );
 
-		$wp_object = get_post( $post_id );
+		$wp_object = \get_post( $post_id );
 
 		// Call the transformer to make the ActivityStreams representation of the event.
 		$event_array = \Activitypub\Transformer\Factory::get_transformer( $wp_object )->to_object()->to_array();
 
 		$this->assertEquals( 'Event', $event_array['type'] );
 		$this->assertEquals( 'MEC Test Event', $event_array['name'] );
-		$this->assertEquals( 'This is the content of the MEC!', wp_strip_all_tags( $event_array['content'] ) );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( 'This is the content of the MEC!', \wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
 		$this->assertTrue( $event_array['commentsEnabled'] );
 		$this->assertEquals( 'allow_all', $event_array['repliesModerationOption'] );
 		$this->assertEquals( 'external', $event_array['joinMode'] );
@@ -128,8 +128,8 @@ class Test_Modern_Events_Calendar_Lite extends \WP_UnitTestCase {
 	 * Test that the transformation of minimal event.
 	 */
 	public function test_modern_events_calendar_lite_event_with_location() {
-		$start_timestamp = strtotime( '+10 days 15:00:00' );
-		$end_timestamp   = strtotime( '+10 days 16:00:00' );
+		$start_timestamp = \strtotime( '+10 days 15:00:00' );
+		$end_timestamp   = \strtotime( '+10 days 16:00:00' );
 
 		// Add new location.
 		$location = array(
@@ -147,14 +147,14 @@ class Test_Modern_Events_Calendar_Lite extends \WP_UnitTestCase {
 			'title'              => 'MEC Test Event',
 			'status'             => 'publish',
 			'content'            => 'This is the content of the MEC!',
-			'start_time_hour'    => gmdate( 'h', $start_timestamp ),
-			'start_time_minutes' => gmdate( 'i', $start_timestamp ),
-			'start_time_ampm'    => gmdate( 'A', $start_timestamp ),
-			'start'              => gmdate( 'Y-m-d', $start_timestamp ),
-			'end'                => gmdate( 'Y-m-d', $end_timestamp ),
-			'end_time_hour'      => gmdate( 'h', $end_timestamp ),
-			'end_time_minutes'   => gmdate( 'i', $end_timestamp ),
-			'end_time_ampm'      => gmdate( 'A', $end_timestamp ),
+			'start_time_hour'    => \gmdate( 'h', $start_timestamp ),
+			'start_time_minutes' => \gmdate( 'i', $start_timestamp ),
+			'start_time_ampm'    => \gmdate( 'A', $start_timestamp ),
+			'start'              => \gmdate( 'Y-m-d', $start_timestamp ),
+			'end'                => \gmdate( 'Y-m-d', $end_timestamp ),
+			'end_time_hour'      => \gmdate( 'h', $end_timestamp ),
+			'end_time_minutes'   => \gmdate( 'i', $end_timestamp ),
+			'end_time_ampm'      => \gmdate( 'A', $end_timestamp ),
 			'repeat_status'      => 0,
 			'repeat_type'        => 'daily',
 			'interval'           => 1,
@@ -163,20 +163,20 @@ class Test_Modern_Events_Calendar_Lite extends \WP_UnitTestCase {
 
 		$post_id = $this->mec_main->save_event( $event );
 
-		$wp_object = get_post( $post_id );
+		$wp_object = \get_post( $post_id );
 
 		// Call the transformer to make the ActivityStreams representation of the event.
 		$event_array = \Activitypub\Transformer\Factory::get_transformer( $wp_object )->to_object()->to_array();
 
 		$this->assertEquals( 'Event', $event_array['type'] );
 		$this->assertEquals( 'MEC Test Event', $event_array['name'] );
-		$this->assertEquals( 'This is the content of the MEC!', wp_strip_all_tags( $event_array['content'] ) );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( 'This is the content of the MEC!', \wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 16:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
 		$this->assertTrue( $event_array['commentsEnabled'] );
 		$this->assertEquals( 'allow_all', $event_array['repliesModerationOption'] );
 		$this->assertEquals( 'external', $event_array['joinMode'] );
-		$this->assertEquals( get_permalink( $wp_object ), $event_array['externalParticipationUrl'] );
+		$this->assertEquals( \get_permalink( $wp_object ), $event_array['externalParticipationUrl'] );
 		$this->assertArrayHasKey( 'location', $event_array );
 		$this->assertEquals( 'MEETING', $event_array['category'] );
 		$this->assertEquals( $location['address'], $event_array['location']['address'] );
diff --git a/tests/includes/activitypub/transformer/class-test-plugin-vs-event-list.php b/tests/includes/activitypub/transformer/class-test-plugin-vs-event-list.php
index 4cb764d..278e565 100644
--- a/tests/includes/activitypub/transformer/class-test-plugin-vs-event-list.php
+++ b/tests/includes/activitypub/transformer/class-test-plugin-vs-event-list.php
@@ -40,21 +40,21 @@ class Test_VS_Event_List extends \WP_UnitTestCase {
 		$this->assertEquals( 1, count( $active_event_plugins ) );
 
 		// Enable ActivityPub support for the event plugin.
-		$this->assertContains( 'event', get_option( 'activitypub_support_post_types' ) );
+		$this->assertContains( 'event', \get_option( 'activitypub_support_post_types' ) );
 
 		// Insert a new Event.
-		$wp_post_id = wp_insert_post(
+		$wp_post_id = \wp_insert_post(
 			array(
 				'post_title'  => 'VSEL Test Event',
 				'post_status' => 'publish',
 				'post_type'   => 'event',
 				'meta_input'  => array(
-					'event-start-date' => strtotime( '+10 days 15:00:00' ),
+					'event-start-date' => \strtotime( '+10 days 15:00:00' ),
 				),
 			)
 		);
 
-		$wp_object = get_post( $wp_post_id );
+		$wp_object = \get_post( $wp_post_id );
 
 		// Call the transformer Factory.
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
@@ -68,7 +68,7 @@ class Test_VS_Event_List extends \WP_UnitTestCase {
 	 */
 	public function test_transform_of_minimal_event() {
 		// Insert a new Event.
-		$wp_post_id = wp_insert_post(
+		$wp_post_id = \wp_insert_post(
 			array(
 				'post_title'  => 'VSEL Test Event',
 				'post_status' => 'publish',
@@ -86,12 +86,12 @@ class Test_VS_Event_List extends \WP_UnitTestCase {
 		$this->assertEquals( 'Event', $event_array['type'] );
 		$this->assertEquals( 'VSEL Test Event', $event_array['name'] );
 		$this->assertEquals( '', $event_array['content'] );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
 		$this->assertArrayNotHasKey( 'endTime', $event_array );
-		$this->assertEquals( comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
-		$this->assertEquals( comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( \comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( \comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
 		$this->assertEquals( 'external', $event_array['joinMode'] );
-		$this->assertEquals( esc_url( get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
+		$this->assertEquals( \esc_url( \get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
 		$this->assertArrayNotHasKey( 'location', $event_array );
 		$this->assertEquals( 'MEETING', $event_array['category'] );
 	}
@@ -101,14 +101,14 @@ class Test_VS_Event_List extends \WP_UnitTestCase {
 	 */
 	public function test_transform_of_full_event() {
 		// Insert a new Event.
-		$wp_post_id = wp_insert_post(
+		$wp_post_id = \wp_insert_post(
 			array(
 				'post_title'  => 'VSEL Test Event',
 				'post_status' => 'publish',
 				'post_type'   => 'event',
 				'meta_input'  => array(
-					'event-start-date' => strtotime( '+10 days 15:00:00' ),
-					'event-date'       => strtotime( '+10 days 16:00:00' ),
+					'event-start-date' => \strtotime( '+10 days 15:00:00' ),
+					'event-date'       => \strtotime( '+10 days 16:00:00' ),
 					'event-link'       => 'https://event-federation.eu/vsel-test-event',
 					'event-link-label' => 'Website',
 				),
@@ -122,12 +122,12 @@ class Test_VS_Event_List extends \WP_UnitTestCase {
 		$this->assertEquals( 'Event', $event_array['type'] );
 		$this->assertEquals( 'VSEL Test Event', $event_array['name'] );
 		$this->assertEquals( '', $event_array['content'] );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
-		$this->assertEquals( comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
-		$this->assertEquals( comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 15:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( \comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( \comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
 		$this->assertEquals( 'external', $event_array['joinMode'] );
-		$this->assertEquals( esc_url( get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
+		$this->assertEquals( \esc_url( \get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
 		$this->assertArrayNotHasKey( 'location', $event_array );
 		$this->assertEquals( 'MEETING', $event_array['category'] );
 		$this->assertContains(
@@ -146,7 +146,7 @@ class Test_VS_Event_List extends \WP_UnitTestCase {
 	 */
 	public function test_transform_of_event_with_hidden_end_time() {
 		// Insert a new Event.
-		$wp_post_id = wp_insert_post(
+		$wp_post_id = \wp_insert_post(
 			array(
 				'post_title'  => 'VSEL Test Event',
 				'post_status' => 'publish',
@@ -171,8 +171,8 @@ class Test_VS_Event_List extends \WP_UnitTestCase {
 	 */
 	public function test_transform_event_with_mapped_categories() {
 		// Create category.
-		$category_id_music   = wp_insert_term( 'Music', 'event_cat', array( 'slug' => 'music' ) );
-		$category_id_theatre = wp_insert_term( 'Theatre', 'event_cat', array( 'slug' => 'theatre' ) );
+		$category_id_music   = \wp_insert_term( 'Music', 'event_cat', array( 'slug' => 'music' ) );
+		$category_id_theatre = \wp_insert_term( 'Theatre', 'event_cat', array( 'slug' => 'theatre' ) );
 
 		// Set default mapping for event categories.
 		update_option( 'event_bridge_for_activitypub_default_event_category', 'MUSIC' );
@@ -187,13 +187,13 @@ class Test_VS_Event_List extends \WP_UnitTestCase {
 				'post_status' => 'publish',
 				'post_type'   => 'event',
 				'meta_input'  => array(
-					'event-start-date'    => strtotime( '+10 days 15:00:00' ),
-					'event-date'          => strtotime( '+10 days 16:00:00' ),
+					'event-start-date'    => \strtotime( '+10 days 15:00:00' ),
+					'event-date'          => \strtotime( '+10 days 16:00:00' ),
 					'event-hide-end-time' => 'yes',
 				),
 			)
 		);
-		wp_set_post_terms( $wp_post_id, $category_id_music['term_id'], 'event_cat' );
+		\wp_set_post_terms( $wp_post_id, $category_id_music['term_id'], 'event_cat' );
 
 		// Call the transformer.
 		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $wp_post_id ) )->to_object()->to_array();
@@ -202,7 +202,7 @@ class Test_VS_Event_List extends \WP_UnitTestCase {
 		$this->assertEquals( 'MUSIC', $event_array['category'] );
 
 		// Change the event category to theatre.
-		wp_set_post_terms( $wp_post_id, $category_id_theatre['term_id'], 'event_cat', false );
+		\wp_set_post_terms( $wp_post_id, $category_id_theatre['term_id'], 'event_cat', false );
 
 		// Call the transformer.
 		$event_array = \Activitypub\Transformer\Factory::get_transformer( get_post( $wp_post_id ) )->to_object()->to_array();
diff --git a/tests/includes/activitypub/transformer/class-test-the-events-calendar.php b/tests/includes/activitypub/transformer/class-test-the-events-calendar.php
index c01254e..f760c70 100644
--- a/tests/includes/activitypub/transformer/class-test-the-events-calendar.php
+++ b/tests/includes/activitypub/transformer/class-test-the-events-calendar.php
@@ -5,7 +5,7 @@
  * @package Event_Bridge_For_ActivityPub
  */
 
-namespace Event_Bridge_For_ActivityPub\Tests\ActivityPub\Transformer;
+namespace Event_Bridge_For_ActivityPup\Tests\ActivityPub\Transformer;
 
 /**
  * Sample test case.
@@ -126,28 +126,28 @@ class Test_The_Events_Calendar extends \WP_UnitTestCase {
 	 */
 	public function test_transform_event_with_mapped_categories() {
 		// Create category.
-		$category_id_music   = wp_insert_term( 'Music', Tribe__Events__Main::TAXONOMY, array( 'slug' => 'music' ) );
-		$category_id_theatre = wp_insert_term( 'Theatre', Tribe__Events__Main::TAXONOMY, array( 'slug' => 'theatre' ) );
+		$category_id_music   = wp_insert_term( 'Music', \Tribe__Events__Main::TAXONOMY, array( 'slug' => 'music' ) );
+		$category_id_theatre = wp_insert_term( 'Theatre', \Tribe__Events__Main::TAXONOMY, array( 'slug' => 'theatre' ) );
 
 		// Set default mapping for event categories.
-		update_option( 'event_bridge_for_activitypub_default_event_category', 'MUSIC' );
+		\update_option( 'event_bridge_for_activitypub_default_event_category', 'MUSIC' );
 
 		// Set an override for the category with the slug theatre.
-		update_option( 'event_bridge_for_activitypub_event_category_mappings', array( 'theatre' => 'THEATRE' ) );
+		\update_option( 'event_bridge_for_activitypub_event_category_mappings', array( 'theatre' => 'THEATRE' ) );
 
 		// Create a The Events Calendar event with the music category.
 		$wp_object = tribe_events()
 			->set_args( self::MOCKUP_EVENTS['minimal_event'] )
 			->create();
 		// Set the post term music to the event.
-		wp_set_post_terms( $wp_object->ID, $category_id_music['term_id'], Tribe__Events__Main::TAXONOMY );
+		wp_set_post_terms( $wp_object->ID, $category_id_music['term_id'], \Tribe__Events__Main::TAXONOMY );
 		// Call the transformer.
 		$event_array = \Activitypub\Transformer\Factory::get_transformer( $wp_object )->to_object()->to_array();
 		// See if the default category mapping is applied.
 		$this->assertEquals( 'MUSIC', $event_array['category'] );
 
 		// Set the post term theatre to the event.
-		wp_set_post_terms( $wp_object->ID, $category_id_theatre['term_id'], Tribe__Events__Main::TAXONOMY, false );
+		wp_set_post_terms( $wp_object->ID, $category_id_theatre['term_id'], \Tribe__Events__Main::TAXONOMY, false );
 		// Call the transformer.
 		$event_array = \Activitypub\Transformer\Factory::get_transformer( $wp_object )->to_object()->to_array();
 		// See if the default category mapping is applied.
diff --git a/tests/includes/activitypub/transformer/class-test-wp-event-manager.php b/tests/includes/activitypub/transformer/class-test-wp-event-manager.php
index 025c3fe..ec8e04e 100644
--- a/tests/includes/activitypub/transformer/class-test-wp-event-manager.php
+++ b/tests/includes/activitypub/transformer/class-test-wp-event-manager.php
@@ -54,7 +54,7 @@ class Test_WP_Event_Manager extends \WP_UnitTestCase {
 			)
 		);
 
-		$wp_object = get_post( $wp_post_id );
+		$wp_object = \get_post( $wp_post_id );
 
 		// Call the transformer Factory.
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
@@ -68,7 +68,7 @@ class Test_WP_Event_Manager extends \WP_UnitTestCase {
 	 */
 	public function test_transform_of_minimal_event() {
 		// Insert a new Event.
-		$wp_post_id = wp_insert_post(
+		$wp_post_id = \wp_insert_post(
 			array(
 				'post_title'   => 'WP Event Manager TestEvent',
 				'post_status'  => 'publish',
@@ -86,13 +86,13 @@ class Test_WP_Event_Manager extends \WP_UnitTestCase {
 		// Check that the event ActivityStreams representation contains everything as expected.
 		$this->assertEquals( 'Event', $event_array['type'] );
 		$this->assertEquals( 'WP Event Manager TestEvent', $event_array['name'] );
-		$this->assertEquals( 'Come to my WP Event Manager event!', wp_strip_all_tags( $event_array['content'] ) );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( 'Come to my WP Event Manager event!', \wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
 		$this->assertArrayNotHasKey( 'endTime', $event_array );
-		$this->assertEquals( comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
-		$this->assertEquals( comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( \comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( \comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
 		$this->assertEquals( 'external', $event_array['joinMode'] );
-		$this->assertEquals( esc_url( get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
+		$this->assertEquals( \esc_url( \get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
 		$this->assertArrayNotHasKey( 'location', $event_array );
 		$this->assertEquals( 'MEETING', $event_array['category'] );
 	}
@@ -102,7 +102,7 @@ class Test_WP_Event_Manager extends \WP_UnitTestCase {
 	 */
 	public function test_transform_of_full_online_event() {
 		// Insert a new Event.
-		$wp_post_id = wp_insert_post(
+		$wp_post_id = \wp_insert_post(
 			array(
 				'post_title'   => 'WP Event Manager TestEvent',
 				'post_status'  => 'publish',
@@ -149,15 +149,15 @@ class Test_WP_Event_Manager extends \WP_UnitTestCase {
 	 */
 	public function test_transform_of_event_with_location() {
 		// Insert a new Event.
-		$wp_post_id = wp_insert_post(
+		$wp_post_id = \wp_insert_post(
 			array(
 				'post_title'   => 'WP Event Manager TestEvent',
 				'post_status'  => 'publish',
 				'post_type'    => 'event_listing',
 				'post_content' => 'Come to my WP Event Manager event!',
 				'meta_input'   => array(
-					'_event_start_date' => \gmdate( 'Y-m-d H:i:s', strtotime( '+10 days 15:00:00' ) ),
-					'_event_end_date'   => \gmdate( 'Y-m-d H:i:s', strtotime( '+10 days 16:00:00' ) ),
+					'_event_start_date' => \gmdate( 'Y-m-d H:i:s', \strtotime( '+10 days 15:00:00' ) ),
+					'_event_end_date'   => \gmdate( 'Y-m-d H:i:s', \strtotime( '+10 days 16:00:00' ) ),
 					'_event_location'   => 'Some text location',
 					'_event_online'     => 'no',
 				),
@@ -170,14 +170,14 @@ class Test_WP_Event_Manager extends \WP_UnitTestCase {
 		// Check that the event ActivityStreams representation contains everything as expected.
 		$this->assertEquals( 'Event', $event_array['type'] );
 		$this->assertEquals( 'WP Event Manager TestEvent', $event_array['name'] );
-		$this->assertEquals( 'Come to my WP Event Manager event!', wp_strip_all_tags( $event_array['content'] ) );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
-		$this->assertEquals( gmdate( 'Y-m-d', strtotime( '+10 days 15:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
-		$this->assertEquals( comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
-		$this->assertEquals( comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
+		$this->assertEquals( 'Come to my WP Event Manager event!', \wp_strip_all_tags( $event_array['content'] ) );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 15:00:00' ) ) . 'T15:00:00Z', $event_array['startTime'] );
+		$this->assertEquals( \gmdate( 'Y-m-d', \strtotime( '+10 days 15:00:00' ) ) . 'T16:00:00Z', $event_array['endTime'] );
+		$this->assertEquals( \comments_open( $wp_post_id ), $event_array['commentsEnabled'] );
+		$this->assertEquals( \comments_open( $wp_post_id ) ? 'allow_all' : 'closed', $event_array['repliesModerationOption'] );
 		$this->assertEquals( 'external', $event_array['joinMode'] );
 		$this->assertEquals( false, $event_array['isOnline'] );
-		$this->assertEquals( esc_url( get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
+		$this->assertEquals( \esc_url( \get_permalink( $wp_post_id ) ), $event_array['externalParticipationUrl'] );
 		$this->assertArrayHasKey( 'location', $event_array );
 		$this->assertEquals( 'Some text location', $event_array['location']['address'] );
 	}
diff --git a/tests/includes/activitypub/transmogrifier/class-test-gatherpress.php b/tests/includes/activitypub/transmogrifier/class-test-gatherpress.php
new file mode 100644
index 0000000..9141a01
--- /dev/null
+++ b/tests/includes/activitypub/transmogrifier/class-test-gatherpress.php
@@ -0,0 +1,148 @@
+<?php
+/**
+ * Test file for the Transmogrifier (import of ActivityPub Event objects) of GatherPress.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since   1.0.0
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Tests\ActivityPub\Transmogrifier;
+
+use Event_Bridge_For_ActivityPub\ActivityPub\Model\Event_Source;
+use GatherPress\Core\Event;
+use GatherPress\Core\Event_Query;
+use WP_REST_Request;
+use WP_REST_Server;
+
+/**
+ * Test class for the Transmogrifier (import of ActivityPub Event objects) of GatherPress.
+ *
+ * @coversDefaultClass \Event_Bridge_For_ActivityPub\ActivityPub\Transmogrifier\GatherPress
+ */
+class Test_GatherPress extends \WP_UnitTestCase {
+	const FOLLOWED_ACTOR = array(
+		'id'      => 'https://remote.example/@organizer',
+		'type'    => 'Person',
+		'inbox'   => 'https://remote.example/@organizer/inbox',
+		'outbox'  => 'https://remote.example/@organizer/outbox',
+		'name'    => 'The Organizer',
+		'summary' => 'Just a random organizer of events in the Fediverse',
+	);
+
+	/**
+	 * Post ID.
+	 *
+	 * @var int
+	 */
+	protected static $event_source_post_id;
+
+	/**
+	 * REST Server.
+	 *
+	 * @var WP_REST_Server
+	 */
+	protected $server;
+
+	/**
+	 * Create fake data before tests run.
+	 */
+	public static function wpSetUpBeforeClass() {
+		// Follow actor.
+		$event_source = Event_Source::init_from_array( self::FOLLOWED_ACTOR );
+		$post_id      = $event_source->save();
+
+		// Save the post ID for usage in tests.
+		self::$event_source_post_id = $post_id;
+	}
+
+	/**
+	 * Set up the test.
+	 */
+	public function set_up() {
+		if ( ! defined( 'GATHERPRESS_CORE_FILE' ) ) {
+			self::markTestSkipped( 'GatherPress plugin is not active.' );
+		}
+
+		\add_option( 'permalink_structure', '/%postname%/' );
+
+		global $wp_rest_server;
+		$wp_rest_server = new WP_REST_Server();
+		$this->server   = $wp_rest_server;
+
+		do_action( 'rest_api_init' );
+
+		\Activitypub\Rest\Server::add_hooks();
+
+		// Mock the plugin activation.
+		\GatherPress\Core\Setup::get_instance()->activate_gatherpress_plugin( false );
+
+		// Make sure that ActivityPub support is enabled for GatherPress.
+		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
+		$aec->activate_activitypub_support_for_active_event_plugins();
+
+		\update_option( 'event_bridge_for_activitypub_event_sources_active', true );
+		\update_option( 'event_bridge_for_activitypub_integration_used_for_event_sources_feature', \Event_Bridge_For_ActivityPub\Integrations\GatherPress::class );
+		\update_option( 'activitypub_actor_mode', ACTIVITYPUB_BLOG_MODE );
+	}
+
+	/**
+	 * Tear down the test.
+	 */
+	public function tear_down() {
+		\delete_option( 'permalink_structure' );
+		\add_filter( 'activitypub_defer_signature_verification', '__return_false' );
+	}
+
+	/**
+	 * Test receiving event from followed actor.
+	 */
+	public function test_incoming_event() {
+		\add_filter( 'activitypub_defer_signature_verification', '__return_true' );
+
+		$json = array(
+			'id'     => 'https://remote.example/@organizer/events/new-year-party#create',
+			'type'   => 'Create',
+			'actor'  => 'https://remote.example/@organizer',
+			'object' => array(
+				'id'        => 'https://remote.example/@organizer/events/new-year-party',
+				'type'      => 'Event',
+				'startTime' => \gmdate( 'Y-m-d\TH:i:s\Z', time() + WEEK_IN_SECONDS ),
+				'endTime'   => \gmdate( 'Y-m-d\TH:i:s\Z', time() + WEEK_IN_SECONDS + HOUR_IN_SECONDS ),
+				'name'      => 'Fediverse Party',
+				'to'        => 'https://www.w3.org/ns/activitystreams#Public',
+				'published' => '2020-01-01T00:00:00Z',
+				'location'  => array(
+					'type'    => 'Place',
+					'name'    => 'Fediverse Concert Hall',
+					'address' => 'Fedistreet 13, Feditown 1337',
+				),
+			),
+		);
+
+		$request = new WP_REST_Request( 'POST', '/activitypub/1.0/users/0/inbox' );
+		$request->set_header( 'Content-Type', 'application/activity+json' );
+		$request->set_body( \wp_json_encode( $json ) );
+
+		// Dispatch the request.
+		$response = \rest_do_request( $request );
+		$this->assertEquals( 202, $response->get_status() );
+
+		// Check if post has been created.
+		$event_query = Event_Query::get_instance();
+		$the_query = $event_query->get_upcoming_events();
+
+		$this->assertEquals( true, $the_query->have_posts() );
+		$this->assertEquals( 1, $the_query->post_count );
+
+		// Initialize new GatherPress Event object.
+		$event = new Event( $the_query->get_posts()[0] );
+
+		$this->assertEquals( $json['object']['name'], $event->event->post_title );
+		$this->assertEquals( $json['object']['startTime'], $event->get_datetime_start( 'Y-m-d\TH:i:s\Z' ) );
+		$this->assertEquals( $json['object']['endTime'], $event->get_datetime_end( 'Y-m-d\TH:i:s\Z' ) );
+		$this->assertEquals( $json['object']['location']['address'], $event->get_venue_information()['full_address'] );
+		$this->assertEquals( $json['object']['location']['name'], $event->get_venue_information()['name'] );
+		$this->assertEquals( false, $event->get_venue_information()['is_online_event'] );
+	}
+}
diff --git a/tests/includes/activitypub/transmogrifier/class-test-the-events-calendar.php b/tests/includes/activitypub/transmogrifier/class-test-the-events-calendar.php
new file mode 100644
index 0000000..6f59712
--- /dev/null
+++ b/tests/includes/activitypub/transmogrifier/class-test-the-events-calendar.php
@@ -0,0 +1,160 @@
+<?php
+/**
+ * Test file for the Transmogrifier (import of ActivityPub Event objects) of GatherPress.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since   1.0.0
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Tests\ActivityPub\Transmogrifier;
+
+use Event_Bridge_For_ActivityPub\ActivityPub\Model\Event_Source;
+use WP_REST_Request;
+use WP_REST_Server;
+
+/**
+ * Test class for the Transmogrifier (import of ActivityPub Event objects) of GatherPress.
+ *
+ * @coversDefaultClass \Event_Bridge_For_ActivityPub\ActivityPub\Transmogrifier\The_Events_Calendar
+ */
+class Test_The_Events_Calendar extends \WP_UnitTestCase {
+	const FOLLOWED_ACTOR = array(
+		'id'      => 'https://remote.example/@organizer',
+		'type'    => 'Person',
+		'inbox'   => 'https://remote.example/@organizer/inbox',
+		'outbox'  => 'https://remote.example/@organizer/outbox',
+		'name'    => 'The Organizer',
+		'summary' => 'Just a random organizer of events in the Fediverse',
+	);
+
+	/**
+	 * Post ID.
+	 *
+	 * @var int
+	 */
+	protected static $event_source_post_id;
+
+	/**
+	 * REST Server.
+	 *
+	 * @var WP_REST_Server
+	 */
+	protected $server;
+
+	/**
+	 * Create fake data before tests run.
+	 */
+	public static function wpSetUpBeforeClass() {
+		// Follow actor.
+		$event_source = Event_Source::init_from_array( self::FOLLOWED_ACTOR );
+		$post_id      = $event_source->save();
+
+		// Save the post ID for usage in tests.
+		self::$event_source_post_id = $post_id;
+	}
+
+	/**
+	 * Set up the test.
+	 */
+	public function set_up() {
+		if ( ! class_exists( '\Tribe__Events__Main' ) ) {
+			self::markTestSkipped( 'The Events Calendar plugin is not active.' );
+		}
+
+		\add_option( 'permalink_structure', '/%postname%/' );
+
+		global $wp_rest_server;
+		$wp_rest_server = new WP_REST_Server();
+		$this->server   = $wp_rest_server;
+
+		do_action( 'rest_api_init' );
+
+		\Activitypub\Rest\Server::add_hooks();
+
+		// Mock the plugin activation.
+		\GatherPress\Core\Setup::get_instance()->activate_gatherpress_plugin( false );
+
+		// Make sure that ActivityPub support is enabled for The Events Calendar.
+		$aec = \Event_Bridge_For_ActivityPub\Setup::get_instance();
+		$aec->activate_activitypub_support_for_active_event_plugins();
+
+		\update_option( 'event_bridge_for_activitypub_event_sources_active', true );
+		\update_option(
+			'event_bridge_for_activitypub_integration_used_for_event_sources_feature',
+			\Event_Bridge_For_ActivityPub\Integrations\The_Events_Calendar::class
+		);
+		\update_option( 'activitypub_actor_mode', ACTIVITYPUB_BLOG_MODE );
+	}
+
+	/**
+	 * Tear down the test.
+	 */
+	public function tear_down() {
+		\delete_option( 'permalink_structure' );
+		\add_filter( 'activitypub_defer_signature_verification', '__return_false' );
+	}
+
+	/**
+	 * Test receiving event from followed actor.
+	 */
+	public function test_incoming_event() {
+		\add_filter( 'activitypub_defer_signature_verification', '__return_true' );
+
+		$json = array(
+			'id'     => 'https://remote.example/@organizer/events/new-year-party#create',
+			'type'   => 'Create',
+			'actor'  => 'https://remote.example/@organizer',
+			'object' => array(
+				'id'        => 'https://remote.example/@organizer/events/new-year-party',
+				'type'      => 'Event',
+				'startTime' => \gmdate( 'Y-m-d\TH:i:s\Z', time() + WEEK_IN_SECONDS ),
+				'endTime'   => \gmdate( 'Y-m-d\TH:i:s\Z', time() + WEEK_IN_SECONDS + HOUR_IN_SECONDS ),
+				'name'      => 'Fediverse Party',
+				'to'        => 'https://www.w3.org/ns/activitystreams#Public',
+				'published' => '2020-01-01T00:00:00Z',
+				'location'  => array(
+					'type'    => 'Place',
+					'name'    => 'Fediverse Concert Hall',
+					'address' => 'Fedistreet 13, Feditown 1337',
+				),
+			),
+		);
+
+		$request = new WP_REST_Request( 'POST', '/activitypub/1.0/users/0/inbox' );
+		$request->set_header( 'Content-Type', 'application/activity+json' );
+		$request->set_body( \wp_json_encode( $json ) );
+
+		// Dispatch the request.
+		$response = \rest_do_request( $request );
+		$this->assertEquals( 202, $response->get_status() );
+
+		// Check if post has been created.
+		$the_query = tribe_get_events();
+
+		$this->assertEquals( true, $the_query->have_posts() );
+		$this->assertEquals( 1, $the_query->post_count );
+
+		// Initialize new GatherPress Event object.
+		$event = tribe_get_event( $the_query->get_posts()[0] );
+
+		$this->assertEquals( $json['object']['name'], $event->post_title );
+		$this->assertEquals( $json['object']['startTime'], $event->start->format( 'Y-m-d\TH:i:s\Z' ) );
+		$this->assertEquals( $json['object']['endTime'], $event->end->format( 'Y-m-d\TH:i:s\Z' ) );
+
+		$venues = $event->venues;
+		// Get first venue. We currently only support a single venue.
+		if ( $venues instanceof \Tribe\Events\Collections\Lazy_Post_Collection ) {
+			$venue = $venues->first();
+		} elseif ( empty( $this->wp_object->venues ) || ! empty( $this->wp_object->venues[0] ) ) {
+			return null;
+		} else {
+			$venue = $venues[0];
+		}
+
+		$this->assertEquals( $json['object']['location']['address'], $venue->address );
+		$this->assertEquals( $json['object']['location']['name'], $venue->post_title );
+
+		\remove_filter( 'activitypub_defer_signature_verification', '__return_true' );
+	}
+}
diff --git a/tests/includes/class-test-event-sources.php b/tests/includes/class-test-event-sources.php
index b9afeea..8209a32 100644
--- a/tests/includes/class-test-event-sources.php
+++ b/tests/includes/class-test-event-sources.php
@@ -13,7 +13,7 @@ use WP_REST_Request;
 use WP_REST_Server;
 
 /**
- * Test class for Activitypub Rest Inbox.
+ * Test class for the Event Sources Feature.
  *
  * @coversDefaultClass \Event_Bridge_For_ActivityPub\Event_Sources
  */
@@ -48,9 +48,9 @@ class Test_Event_Sources extends \WP_UnitTestCase {
 	 */
 	public static function wpSetUpBeforeClass( $factory ) {
 		// Follow actor.
-		$event_source = new \Event_Bridge_For_ActivityPub\ActivityPub\Model\Event_Source();
-		$event_source->from_array( self::FOLLOWED_ACTOR );
-		$post_id     = $event_source->save();
+		$event_source = \Event_Bridge_For_ActivityPub\ActivityPub\Model\Event_Source::init_from_array( self::FOLLOWED_ACTOR );
+		$post_id      = $event_source->save();
+
 		self::$event_source_post_id = $post_id;
 	}