diff --git a/bin/install-wp-tests.sh b/bin/install-wp-tests.sh
index 1c036e2..36fd652 100755
--- a/bin/install-wp-tests.sh
+++ b/bin/install-wp-tests.sh
@@ -92,7 +92,7 @@ install_wp() {
 		tar --strip-components=1 -zxmf $TMPDIR/wordpress.tar.gz -C $WP_CORE_DIR
 	fi
 
-	download https://raw.github.com/markoheijnen/wp-mysqli/master/db.php $WP_CORE_DIR/wp-content/db.php
+	download https://raw.githubusercontent.com/markoheijnen/wp-mysqli/master/db.php $WP_CORE_DIR/wp-content/db.php
 }
 
 install_test_suite() {
@@ -176,6 +176,11 @@ install_db() {
 	fi
 }
 
+install_gp() {
+	git clone --branch develop --single-branch -q https://github.com/GlotPress/GlotPress.git "$WP_CORE_DIR/wp-content/plugins/glotpress"
+}
+
 install_wp
 install_test_suite
 install_db
+install_gp
diff --git a/inc/class-anniversary.php b/inc/class-anniversary.php
index d031bc0..1ec2dcb 100644
--- a/inc/class-anniversary.php
+++ b/inc/class-anniversary.php
@@ -13,6 +13,9 @@
  * Sends an email to translators in their translation anniversary.
  */
 class Anniversary {
+	/**
+	 * Constructor.
+	 */
 	public function __construct() {
 		add_action( 'wporg_translate_notification_anniversary', array( $this, 'send_email_to_translator' ), 10, 3 );
 		add_action( 'wporg_translate_notification_summary_anniversary', array( $this, 'send_slack_notification' ), 10, 2 );
@@ -103,8 +106,8 @@ private function get_translators_in_anniversary( ?array $users ): array {
 	 */
 	private function get_number_of_translations( int $user_id ): int {
 		global $wpdb;
-		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
 		return intval(
+			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
 			$wpdb->get_var(
 				$wpdb->prepare(
 					"SELECT COUNT(id)
@@ -120,9 +123,9 @@ private function get_number_of_translations( int $user_id ): int {
 	/**
 	 * Send an email to the translators.
 	 *
-	 * @param int $user_id      The user_id of the anniversary user.
+	 * @param int    $user_id      The user_id of the anniversary user.
 	 * @param string $date      The user's first translation date (Y-m-d format).
-	 * @param int $number_of_translations The number of translations made so far.
+	 * @param int    $number_of_translations The number of translations made so far.
 	 *
 	 * @return void
 	 */
@@ -139,7 +142,7 @@ public function send_email_to_translator( int $user_id, string $date, int $numbe
 		$message = sprintf(
 		// translators: Email body. %1$s: Display name. %2$d: number of years since the first translation. %3$d: number of translations.
 			_n(
-					'
+				'
 Dear %1$s,
 <br><br>
 do you remember? On this day, %2$d year ago, you contributed your first translation to translate.wordpress.org.
@@ -150,7 +153,7 @@ public function send_email_to_translator( int $user_id, string $date, int $numbe
 <br><br>
 The Global Polyglots Team
 ',
-					'
+				'
 Dear %1$s,
 <br><br>
 do you remember? On this day, %2$d years ago, you contributed your first translation to translate.wordpress.org.
diff --git a/inc/class-consistency.php b/inc/class-consistency.php
index f435ca2..4ecd711 100644
--- a/inc/class-consistency.php
+++ b/inc/class-consistency.php
@@ -19,6 +19,9 @@ class Consistency {
 	 */
 	private array $months_to_notify = array( 48, 24, 12, 6 );
 
+	/**
+	 * Constructor.
+	 */
 	public function __construct() {
 		add_action( 'wporg_translate_notification_consistency', array( $this, 'send_email_to_translator' ), 10, 2 );
 		add_action( 'wporg_translate_notification_summary_consistency', array( $this, 'send_slack_notification' ) );
@@ -111,11 +114,12 @@ private function get_users_with_consistency_last_months( int $months = 6 ): arra
 	/**
 	 * Send an email to the translators.
 	 *
-	 * @param array $users_to_notify The users to notify.
+	 * @param int $months  The number of months.
+	 * @param int $user_id The user ID.
 	 *
 	 * @return void
 	 */
-	public function send_email_to_translators( $months, $user_id ): void {
+	public function send_email_to_translators( int $months, int $user_id ): void {
 		$years = intdiv( $months, 12 );
 		// Translators: Number of years or months of translation consistency, to be used in the email subject.
 		$time_period = $years > 0 ? sprintf( _n( '%d year', '%d years', $years, 'wporg-gp-engagement' ), $years ) : sprintf( _n( '%d month', '%d months', $months, 'wporg-gp-engagement' ), $months );
@@ -158,12 +162,12 @@ public function send_email_to_translators( $months, $user_id ): void {
 	}
 
 	/**
-	 * Send a Slack notification to the users
+	 * Send a Slack notification about the notified users
 	 *
-	 * @param array $users_to_notify The users to notify.
+	 * @param array $users_notified The users that were notify.
 	 */
-	public function send_slack_notifications( array $users_to_notify ) {
-		foreach ( $users_to_notify as $months => $user_ids ) {
+	public function send_slack_notifications( array $users_notified ) {
+		foreach ( $users_notified as $months => $user_ids ) {
 			$years = intdiv( $months, 12 );
 			// Translators: Number of years or months of translation consistency, to be used in the Slack message.
 			$time_period = $years > 0 ? sprintf( _n( '%d year', '%d years', $years, 'wporg-gp-engagement' ), $years ) : sprintf( _n( '%d month', '%d months', $months, 'wporg-gp-engagement' ), $months );
diff --git a/inc/class-first-translation.php b/inc/class-first-translation.php
index f284806..bb65725 100644
--- a/inc/class-first-translation.php
+++ b/inc/class-first-translation.php
@@ -15,6 +15,9 @@
  * Sends an email to translators who for the first time had a translation approved.
  */
 class First_Translation {
+	/**
+	 * Constructor.
+	 */
 	public function __construct() {
 		add_action( 'wporg_translate_notification_first_translation', array( $this, 'send_email_to_translator' ) );
 		add_action( 'wporg_translate_notification_summary_first_translation', array( $this, 'send_slack_notification' ) );
@@ -41,7 +44,6 @@ public function __invoke( ?GP_Translation $translation ) {
 		do_action( 'wporg_translate_notification_first_translation', $translation );
 		$this->update_user_option( $translation->user_id );
 		do_action( 'wporg_translate_notification_summary_first_translation', $translation );
-
 	}
 
 	/**
diff --git a/inc/class-inactive.php b/inc/class-inactive.php
index 40b1761..2339a02 100644
--- a/inc/class-inactive.php
+++ b/inc/class-inactive.php
@@ -14,22 +14,25 @@
  * Sends an email to translators in their translation anniversary.
  */
 class Inactive {
+	/**
+	 * Constructor.
+	 */
 	public function __construct() {
 		add_action( 'wporg_translate_notification_inactive', array( $this, 'send_email_to_translator' ) );
 		add_action( 'wporg_translate_notification_summary_inactive', array( $this, 'send_slack_notification' ) );
 	}
 		/**
-	 * Send an email to translators who have been inactive in the last years.
-	 *
-	 * @return void
-	 */
+		 * Send an email to translators who have been inactive in the last years.
+		 *
+		 * @return void
+		 */
 	public function __invoke() {
 			$one_year_ago   = ( new DateTime() )->modify( '-1 year' )->format( 'Y-m-d' );
 			$all_users      = $this->get_users_with_translation_on_date( $one_year_ago );
 			$inactive_users = $this->get_inactive_users( $all_users, $one_year_ago );
-			foreach ( $inactive_users as $user_id ) {
-				do_action( 'wporg_translate_notification_inactive', $user_id );
-			}
+		foreach ( $inactive_users as $user_id ) {
+			do_action( 'wporg_translate_notification_inactive', $user_id );
+		}
 
 			do_action( 'wporg_translate_notification_summary_inactive', $inactive_users );
 	}
diff --git a/inc/class-plugin.php b/inc/class-plugin.php
index fcfb728..4e7c860 100644
--- a/inc/class-plugin.php
+++ b/inc/class-plugin.php
@@ -112,9 +112,4 @@ public function wp_schedule_crons() {
 			wp_schedule_event( $timestamp, 'monthly', 'gp_engagement_consistency' );
 		}
 	}
-
-	public function send_notification_email( $user, $subject, $message ) {
-		$email = new Notification();
-		$email->send_email( $user, $subject, $message );
-	}
 }
diff --git a/inc/class-translation-milestone.php b/inc/class-translation-milestone.php
index 10793f7..dc7374f 100644
--- a/inc/class-translation-milestone.php
+++ b/inc/class-translation-milestone.php
@@ -34,6 +34,9 @@ class Translation_Milestone {
 		1000000,
 	);
 
+	/**
+	 * Constructor.
+	 */
 	public function __construct() {
 		add_action( 'wporg_translate_notification_milestone', array( $this, 'send_email_to_translator' ), 10, 2 );
 		add_action( 'wporg_translate_notification_summary_milestone', array( $this, 'send_slack_notification' ), 10, 2 );
diff --git a/phpcs.xml b/phpcs.xml
index 79d4c42..0ddacba 100644
--- a/phpcs.xml
+++ b/phpcs.xml
@@ -7,6 +7,10 @@
     <file>.</file>
     <file>inc</file>
 
+    <rule ref="WordPress.Files.FileName.InvalidClassFileName">
+        <exclude-pattern>tests/*</exclude-pattern>
+    </rule>
+
     <!-- Exclude the vendor directory -->
     <exclude-pattern>*/vendor/*</exclude-pattern>
 
@@ -17,4 +21,4 @@
 
     <!-- Additional arguments -->
     <arg name="basepath" value="."/>
-</ruleset>
\ No newline at end of file
+</ruleset>
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 9ee8f4e..3407df6 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -1,10 +1,21 @@
 <?php
+/**
+ * GlotPress Engagement Tests Bootstrap.
+ *
+ * @package wporg-gp-engagement
+ */
 
 $_tests_dir = getenv( 'WP_TESTS_DIR' );
 if ( ! $_tests_dir ) {
 	$_tests_dir = rtrim( sys_get_temp_dir(), '/\\' ) . '/wordpress-tests-lib';
 }
 
+/**
+ * Get the path to the GlotPress repository.
+ *
+ * @param string $path The path to append to the GlotPress repository path.
+ * @return string The full path to the GlotPress repository.
+ */
 function _glotpress_path( string $path ): string {
 	$glotpress_path = dirname( __DIR__, 2 ) . '/glotpress/';
 	if ( getenv( 'GITHUB_ACTIONS' ) ) {
@@ -47,4 +58,3 @@ function _manually_load_plugin() {
 require_once _glotpress_path( '/tests/phpunit/lib/testcase.php' );
 require_once _glotpress_path( '/tests/phpunit/lib/testcase-route.php' );
 require_once _glotpress_path( '/tests/phpunit/lib/testcase-request.php' );
-
diff --git a/tests/test-anniversary.php b/tests/test-anniversary.php
index 7dbfde4..5854952 100644
--- a/tests/test-anniversary.php
+++ b/tests/test-anniversary.php
@@ -1,33 +1,53 @@
 <?php
+/**
+ * Tests for the Anniversary class.
+ *
+ * @package wporg-gp-engagement
+ */
+
 namespace WordPressdotorg\GlotPress\Engagement;
 
+/**
+ * Test the Anniversary class.
+ */
 class Anniversary_Test extends \GP_UnitTestCase {
-
+	/**
+	 * Data provider for the anniversary tests.
+	 *
+	 * @return array
+	 */
 	public function anniversary_data_provider() {
 		return array(
-			'today' => array( time(), 0 ),
-			'1 years ago' => array( strtotime( '-1 year' ), 1 ),
+			'today'         => array( time(), 0 ),
+			'1 years ago'   => array( strtotime( '-1 year' ), 1 ),
 			'1.5 years ago' => array( strtotime( '-1.5 year' ), 0 ),
-			'2 years ago' => array( strtotime( '-2 year' ), 1 ),
+			'2 years ago'   => array( strtotime( '-2 year' ), 1 ),
 		);
 	}
 
 	/**
+	 * Test the anniversary notification
+	 *
 	 * @dataProvider anniversary_data_provider
+	 *
+	 * @param int $date     The date to test.
+	 * @param int $expected The expected number of calls to the mock action.
 	 */
 	public function test_anniversary( $date, $expected ) {
 
 		$user = $this->factory->user->create();
 
-		$translation = $this->factory->translation->create( array(
-			'status' => 'current',
-			'locale' => 'en',
-			'translation_set_id' => 1,
-			'user_id' => $user,
-			'user_id_last_modified' => $user,
-		) );
+		$translation = $this->factory->translation->create(
+			array(
+				'status'                => 'current',
+				'locale'                => 'en',
+				'translation_set_id'    => 1,
+				'user_id'               => $user,
+				'user_id_last_modified' => $user,
+			)
+		);
 
-		$translation->update( array( 'date_added' => date( 'Y-m-d H:i:s', $date ) ) );
+		$translation->update( array( 'date_added' => gmdate( 'Y-m-d H:i:s', $date ) ) );
 
 		remove_all_actions( 'wporg_translate_notification_milestone' );
 		remove_all_actions( 'wporg_translate_notification_summary_milestone' );
diff --git a/tests/test-consistency.php b/tests/test-consistency.php
index 923697d..9915bf4 100644
--- a/tests/test-consistency.php
+++ b/tests/test-consistency.php
@@ -1,5 +1,14 @@
 <?php
+/**
+ * Tests for the Consistency class.
+ *
+ * @package wporg-gp-engagement
+ */
+
 namespace WordPressdotorg\GlotPress\Engagement;
 
+/**
+ * Test the Consistency class.
+ */
 class Consistency_Test {
 }
diff --git a/tests/test-first-translation.php b/tests/test-first-translation.php
index 50a3529..3ef737a 100644
--- a/tests/test-first-translation.php
+++ b/tests/test-first-translation.php
@@ -1,4 +1,14 @@
 <?php
+/**
+ * Tests for the First_Translation class.
+ *
+ * @package wporg-gp-engagement
+ */
+
 namespace WordPressdotorg\GlotPress\Engagement;
+
+/**
+ * Test the First_Translation class.
+ */
 class First_Translation_Test {
 }
diff --git a/tests/test-inactive.php b/tests/test-inactive.php
index b75c4b4..1fa6194 100644
--- a/tests/test-inactive.php
+++ b/tests/test-inactive.php
@@ -1,5 +1,14 @@
 <?php
+/**
+ * Tests for the Inactive class.
+ *
+ * @package wporg-gp-engagement
+ */
+
 namespace WordPressdotorg\GlotPress\Engagement;
 
+/**
+ * Test the Inactive class.
+ */
 class Inactive_Test {
 }
diff --git a/tests/test-translation-milestone.php b/tests/test-translation-milestone.php
index 29f1aa5..7614098 100644
--- a/tests/test-translation-milestone.php
+++ b/tests/test-translation-milestone.php
@@ -1,5 +1,14 @@
 <?php
+/**
+ * Tests for the Translation_Milestone class.
+ *
+ * @package wporg-gp-engagement
+ */
+
 namespace WordPressdotorg\GlotPress\Engagement;
 
+/**
+ * Test the Translation_Milestone class.
+ */
 class Translation_Milestone_Test {
 }