diff --git a/.forgejo/workflows/phpunit.yml b/.forgejo/workflows/phpunit.yml
index 23321d9..f4a03dd 100644
--- a/.forgejo/workflows/phpunit.yml
+++ b/.forgejo/workflows/phpunit.yml
@@ -37,7 +37,7 @@ jobs:
           path: |
             ${{ env.WP_CORE_DIR }}
             ${{ env.WP_TESTS_DIR }}
-          key: cache-wordpress-3
+          key: cache-wordpress-4
 
       - name: Cache Composer
         id: cache-composer-phpunit
@@ -74,7 +74,12 @@ jobs:
         if: steps.cache-wordpress.outputs.cache-hit != 'false'
         run: bash bin/install-wp-tests.sh wordpress_test root root 127.0.0.1 6.6 false true true true
 
-      - name: Run PHPUnit
-        run: cd /workspace/Event-Federation/wordpress-activitypub-event-extensions/ && ./vendor/bin/phpunit
+      - name: Run Integration tests for The Events Calendar
+        run: cd /workspace/Event-Federation/wordpress-activitypub-event-extensions/ && ./vendor/bin/phpunit --filter=the_events_calendar
+        env:
+          PHP_VERSION: ${{ matrix.php-version }}
+
+      - name: Run Integration tests for VS Event List
+        run: cd /workspace/Event-Federation/wordpress-activitypub-event-extensions/ && ./vendor/bin/phpunit --filter=vs_event_list
         env:
           PHP_VERSION: ${{ matrix.php-version }}
diff --git a/bin/install-wp-tests.sh b/bin/install-wp-tests.sh
index ff43d3a..8d495bf 100755
--- a/bin/install-wp-tests.sh
+++ b/bin/install-wp-tests.sh
@@ -209,7 +209,12 @@ install_wp_plugin() {
 
 	# Get the latest tag.
     LATEST_TAG=$(svn log https://plugins.svn.wordpress.org/$PLUGIN_NAME/tags --limit 1 | awk 'NR == 4 { print $4 }')
-	PLUGIN_FILE="$PLUGIN_NAME.$LATEST_TAG.zip"
+	if [ -n "$LATEST_TAG" ]; then
+		PLUGIN_FILE="$PLUGIN_NAME.$LATEST_TAG.zip"
+	else
+		PLUGIN_FILE="$PLUGIN_NAME.zip"
+	fi
+
 	URL="https://downloads.wordpress.org/plugin/$PLUGIN_FILE"
 
     # Check if the plugin file already exists
@@ -226,16 +231,13 @@ install_wp_plugins() {
         echo "Skipping WordPress plugin installation."
         return 0
     fi
-	# Always install the ActivityPub plugin.
+	# Install the one and only ActivityPub plugin (greetings @pfefferle).
 	install_wp_plugin activitypub
+	# Install (not-activate) all supported event plugins.
 	install_wp_plugin the-events-calendar
-	# Install additional plugins.
-	# if [[ -n "$PLUGINS" ]]; then
-	# 	IFS=',' read -ra PLUGIN_ARRAY <<< "$PLUGINS"
-	# 	for plugin in "${PLUGIN_ARRAY[@]}"; do
-	# 		install_wp_plugin "$plugin"
-	# 	done
-	# fi
+	install_wp_plugin very-simple-event-list
+	install_wp_plugin gatherpress
+	install_wp_plugin events-manager
 }
 
 install_wp
diff --git a/composer.json b/composer.json
index ba5b52a..d4048d0 100644
--- a/composer.json
+++ b/composer.json
@@ -41,10 +41,20 @@
         "lint:fix": [
             "vendor/bin/phpcbf"
         ],
-        "test": [
+        "prepare-test": [
             "composer install",
-            "bin/install-wp-tests.sh wordpress-test root wordpress-test test-db latest true",
-            "phpunit"
-        ]
+            "bin/install-wp-tests.sh wordpress-test root wordpress-test test-db latest true"
+        ],
+        "test": [
+            "@prepare-test",
+            "@test-vs-event-list",
+            "@test-the-events-calendar",
+            "@test-gatherpress",
+            "@test-events-manager"
+        ],
+        "test-vs-event_list": "phpunit --filter=vs_event_list",
+        "test-the-events-calendar": "phpunit --filter=the_events_calendar",
+        "test-gatherpress": "phpunit --filter=gatherpress",
+        "test-events-manager": "phpunit --filter=events-manager"
     }
 }
diff --git a/docker-compose.yml b/docker-compose.yml
index 47d5117..a1d0658 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -26,10 +26,10 @@ services:
       MARIADB_ROOT_PASSWORD: wordpress-test
     healthcheck:
       test: ["CMD", "healthcheck.sh", "--connect", "--innodb_initialized"]
-      start_period: 5s
-      interval: 4s
+      start_period: 2s
+      interval: 1s
       timeout: 5s
-      retries: 5
+      retries: 10
 
   test-php:
     build:
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index e32baa7..c586a84 100755
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -30,17 +30,46 @@ require_once "{$_tests_dir}/includes/functions.php";
  */
 function _manually_load_plugin() {
 	$plugin_dir = ABSPATH . '/wp-content/plugins/';
+
+	// Always manually load the ActivityPub plugin.
 	require_once $plugin_dir . 'activitypub/activitypub.php';
-	$event_plugin = 'the-events-calendar';
-	switch ( $event_plugin ) {
-		case 'the-events-calendar':
-			$plugin_file = 'the-events-calendar/the-events-calendar.php';
-			require_once $plugin_dir . $plugin_file;
-			$current   = get_option( 'active_plugins', array() );
-			$current[] = $plugin_file;
-			sort( $current );
-			update_option( 'active_plugins', $current );
+
+	// Capture the --filter argument.
+	$activitypub_event_extension_integration_filter = null;
+	foreach ( $_SERVER['argv'] as $arg ) {
+		if ( strpos( $arg, '--filter=' ) === 0 ) {
+			$activitypub_event_extension_integration_filter = substr( $arg, strlen( '--filter=' ) );
+			break;
+		}
 	}
+
+	$plugin_file = null;
+	// See if we want to run integration tests for a specific event-plugin.
+	switch ( $activitypub_event_extension_integration_filter ) {
+		case 'the_events_calendar':
+			$plugin_file = 'the-events-calendar/the-events-calendar.php';
+			break;
+		case 'vs_event_list':
+			$plugin_file = 'very-simple-event-list/vsel.php';
+			break;
+		case 'events_manager':
+			$plugin_file = 'events-manager/events-manager.php';
+			break;
+		case 'gatherpress':
+			$plugin_file = 'gatherpress/gatherpress.php';
+			break;
+	}
+
+	if ( $plugin_file ) {
+		// Manually load the event plugin.
+		require_once $plugin_dir . $plugin_file;
+		$current   = get_option( 'active_plugins', array() );
+		$current[] = $plugin_file;
+		sort( $current );
+		update_option( 'active_plugins', $current );
+	}
+
+	// At last manually load our WordPress plugin.
 	require dirname( __DIR__ ) . '/activitypub-event-extensions.php';
 }
 
diff --git a/tests/test-class-plugin-the-events-calendar.php b/tests/test-class-plugin-the-events-calendar.php
index 3f161f7..424a420 100644
--- a/tests/test-class-plugin-the-events-calendar.php
+++ b/tests/test-class-plugin-the-events-calendar.php
@@ -72,7 +72,7 @@ class Test_The_Events_Calendar extends WP_UnitTestCase {
 	/**
 	 * Test that the right transformer gets applied.
 	 */
-	public function test_transformer_class() {
+	public function test_the_events_calendar_transformer_class() {
 		// We only test for one event plugin being active at the same time,
 		// even though we support multiple onces in theory.
 		// But testing all combinations is beyond scope.