diff --git a/includes/event/event-form-handler.php b/includes/event/event-form-handler.php
index 9e1aad09..20c5e979 100644
--- a/includes/event/event-form-handler.php
+++ b/includes/event/event-form-handler.php
@@ -21,26 +21,35 @@ public function __construct( DateTimeImmutable $now, Event_Repository $event_rep
 	}
 
 	public function handle( array $form_data ): void {
+		$response = $this->process_form( $form_data );
+		if ( is_wp_error( $response ) ) {
+			$status_code = $response->get_error_data( 'status' );
+			wp_send_json_error( $response->get_error_message(), $status_code );
+		}
+		wp_send_json_success( $response );
+	}
+
+	public function process_form( array $form_data ) {
 		if ( ! is_user_logged_in() ) {
-			wp_send_json_error( esc_html__( 'The user must be logged in.', 'gp-translation-events' ), 403 );
+			return new WP_Error( 'not_logged_in', esc_html__( 'The user must be logged in.', 'gp-translation-events' ), array( 'status' => 403 ) );
 		}
 
 		$action = isset( $form_data['form_name'] ) ? sanitize_text_field( wp_unslash( $form_data['form_name'] ) ) : '';
 		if ( ! in_array( $action, array( 'create_event', 'edit_event', 'trash_event' ), true ) ) {
-			wp_send_json_error( esc_html__( 'Invalid form name.', 'gp-translation-events' ), 403 );
+			return new WP_Error( 'form_name_error', esc_html__( 'Invalid form name.', 'gp-translation-events' ), array( 'status' => 403 ) );
 		}
 
 		$event_id = isset( $form_data['event_id'] ) ? intval( sanitize_text_field( wp_unslash( $form_data['event_id'] ) ) ) : 0;
 		$event    = null;
 
 		if ( 'create_event' === $action && ( ! current_user_can( 'create_translation_event' ) ) ) {
-			wp_send_json_error( esc_html__( 'You do not have permissions to create events.', 'gp-translation-events' ), 403 );
+			return new WP_Error( 'permission_error', esc_html__( 'You do not have permissions to create events.', 'gp-translation-events' ), array( 'status' => 403 ) );
 		}
 		if ( 'edit_event' === $action && ( ! current_user_can( 'edit_translation_event', $event_id ) ) ) {
-			wp_send_json_error( esc_html__( 'You do not have permissions to edit this event.', 'gp-translation-events' ), 403 );
+			return new WP_Error( 'permission_error', esc_html__( 'You do not have permissions to edit this event.', 'gp-translation-events' ), array( 'status' => 403 ) );
 		}
 		if ( 'trash_event' === $action && ( ! current_user_can( 'trash_translation_event', $event_id ) ) ) {
-			wp_send_json_error( esc_html__( 'You do not have permissions to delete this event.', 'gp-translation-events' ), 403 );
+			return new WP_Error( 'permission_error', esc_html__( 'You do not have permissions to delete this event.', 'gp-translation-events' ), array( 'status' => 403 ) );
 		}
 
 		$is_nonce_valid = false;
@@ -52,7 +61,7 @@ public function handle( array $form_data ): void {
 			}
 		}
 		if ( ! $is_nonce_valid ) {
-			wp_send_json_error( esc_html__( 'Nonce verification failed.', 'gp-translation-events' ), 403 );
+			return new WP_Error( 'invalid_nonce', esc_html__( 'Nonce verification failed.', 'gp-translation-events' ), array( 'status' => 403 ) );
 		}
 
 		$response_message = '';
@@ -63,17 +72,17 @@ public function handle( array $form_data ): void {
 		if ( 'trash_event' === $action ) {
 			// Trash event.
 			if ( ! $event ) {
-				wp_send_json_error( esc_html__( 'Event does not exist.', 'gp-translation-events' ), 404 );
+				return new WP_Error( 'inexistent_event', esc_html__( 'Event does not exist.', 'gp-translation-events' ), array( 'status' => 404 ) );
 			}
 
 			$stats_calculator = new Stats_Calculator();
 			try {
 				$event_stats = $stats_calculator->for_event( $event->id() );
 			} catch ( Exception $e ) {
-				wp_send_json_error( esc_html__( 'Failed to calculate event stats.', 'gp-translation-events' ), 500 );
+				return new WP_Error( 'stats_calculation_error', esc_html__( 'Failed to calculate event stats.', 'gp-translation-events' ), array( 'status' => 500 ) );
 			}
 			if ( ! empty( $event_stats->rows() ) ) {
-				wp_send_json_error( esc_html__( 'Event has stats so it cannot be deleted.', 'gp-translation-events' ), 422 );
+				return new WP_Error( 'cannot_delete_event', esc_html__( 'Event has stats so it cannot be deleted.', 'gp-translation-events' ), array( 'status' => 422 ) );
 			}
 
 			if ( false === $this->event_repository->trash_event( $event ) ) {
@@ -90,35 +99,30 @@ public function handle( array $form_data ): void {
 			try {
 				$new_event = $this->parse_form_data( $form_data );
 			} catch ( InvalidTimeZone $e ) {
-				wp_send_json_error( esc_html__( 'Invalid time zone.', 'gp-translation-events' ), 422 );
-				return;
+				return new WP_Error( 'invalid_timezone', esc_html__( 'Invalid time zone.', 'gp-translation-events' ), array( 'status' => 422 ) );
 			} catch ( InvalidStart $e ) {
-				wp_send_json_error( esc_html__( 'Invalid start date.', 'gp-translation-events' ), 422 );
-				return;
+				return new WP_Error( 'invalid_start_date', esc_html__( 'Invalid start date.', 'gp-translation-events' ), array( 'status' => 422 ) );
 			} catch ( InvalidEnd $e ) {
-				wp_send_json_error( esc_html__( 'Invalid end date.', 'gp-translation-events' ), 422 );
-				return;
+				return new WP_Error( 'invalid_end_date', esc_html__( 'Invalid end date.', 'gp-translation-events' ), array( 'status' => 422 ) );
 			} catch ( InvalidStatus $e ) {
-				wp_send_json_error( esc_html__( 'Invalid status.', 'gp-translation-events' ), 422 );
-				return;
+				return new WP_Error( 'invalid_status', esc_html__( 'Invalid status.', 'gp-translation-events' ), array( 'status' => 422 ) );
 			}
 
 			if ( empty( $new_event->title() ) ) {
-				wp_send_json_error( esc_html__( 'Invalid title.', 'gp-translation-events' ), 422 );
-				return;
+				return new WP_Error( 'invalid_title', esc_html__( 'Invalid title.', 'gp-translation-events' ), array( 'status' => 422 ) );
 			}
 
 			// This is a list of slugs that are not allowed, as they conflict with the event URLs.
 			$invalid_slugs = array( 'new', 'edit', 'attend', 'my-events' );
 			if ( in_array( sanitize_title( $new_event->title() ), $invalid_slugs, true ) ) {
-				wp_send_json_error( esc_html__( 'Invalid slug.', 'gp-translation-events' ), 422 );
+				return new WP_Error( 'invalid_slug', esc_html__( 'Invalid slug.', 'gp-translation-events' ), array( 'status' => 422 ) );
 			}
 
 			if ( 'create_event' === $action ) {
 				$result = $this->event_repository->insert_event( $new_event );
 				if ( $result instanceof WP_Error ) {
-					wp_send_json_error( esc_html__( 'Failed to create event.', 'gp-translation-events' ), 422 );
-					return;
+					return new WP_Error( 'cannot_create_event', esc_html__( 'Failed to create event.', 'gp-translation-events' ), array( 'status' => 422 ) );
+
 				}
 				$response_message = esc_html__( 'Event created successfully.', 'gp-translation-events' );
 				$this->notifications_schedule->schedule_emails( $result );
@@ -126,7 +130,7 @@ public function handle( array $form_data ): void {
 			if ( 'edit_event' === $action ) {
 				$event = $this->event_repository->get_event( $new_event->id() );
 				if ( ! $event ) {
-					wp_send_json_error( esc_html__( 'Event does not exist.', 'gp-translation-events' ), 404 );
+					return new WP_Error( 'inexistent_event', esc_html__( 'Event does not exist.', 'gp-translation-events' ), array( 'status' => 404 ) );
 				}
 
 				try {
@@ -153,14 +157,14 @@ public function handle( array $form_data ): void {
 						$event->set_attendance_mode( $new_event->attendance_mode() );
 					}
 				} catch ( Exception $e ) {
-					wp_send_json_error( esc_html__( 'Failed to update event.', 'gp-translation-events' ), 422 );
-					return;
+					return new WP_Error( 'cannot_update_event', esc_html__( 'Failed to update event.', 'gp-translation-events' ), array( 'status' => 422 ) );
+
 				}
 
 				$result = $this->event_repository->update_event( $event );
 				if ( $result instanceof WP_Error ) {
-					wp_send_json_error( esc_html__( 'Failed to update event.', 'gp-translation-events' ), 422 );
-					return;
+					return new WP_Error( 'cannot_update_event', esc_html__( 'Failed to update event.', 'gp-translation-events' ), array( 'status' => 422 ) );
+
 				}
 				$response_message = esc_html__( 'Event updated successfully', 'gp-translation-events' );
 				$this->notifications_schedule->schedule_emails( $result );
@@ -170,7 +174,7 @@ public function handle( array $form_data ): void {
 			$event_status = $new_event->status();
 		}
 
-		wp_send_json_success(
+		return(
 			array(
 				'message'       => $response_message,
 				'eventId'       => $event_id,
diff --git a/tests/event/event-form-handler.php b/tests/event/event-form-handler.php
new file mode 100644
index 00000000..0519a8b4
--- /dev/null
+++ b/tests/event/event-form-handler.php
@@ -0,0 +1,103 @@
+<?php
+
+namespace Wporg\Tests\Event;
+
+use Wporg\Tests\Base_Test;
+use Wporg\TranslationEvents\Attendee\Attendee_Repository;
+use Wporg\TranslationEvents\Event\Event_Repository;
+use Wporg\TranslationEvents\Event\Event_Form_Handler;
+use Wporg\TranslationEvents\Tests\Event_Form_Handler_Factory;
+
+class Event_Form_Handler_Test extends Base_Test {
+	private Event_Repository $event_repository;
+	private Attendee_Repository $attendee_repository;
+	private Event_Form_Handler $event_form_handler;
+	private Event_Form_Handler_Factory $event_form_handler_factory;
+
+	public function setUp(): void {
+		parent::setUp();
+		$this->attendee_repository        = new Attendee_Repository();
+		$this->event_repository           = new Event_Repository( $this->now, $this->attendee_repository );
+		$this->event_form_handler         = new Event_Form_Handler( $this->now, $this->event_repository );
+		$this->event_form_handler_factory = new Event_Form_Handler_Factory();
+		$this->set_normal_user_as_current();
+	}
+
+	/**
+	 * Test that the user must be logged in to create an event.
+	 *
+	 * @return void
+	 */
+	public function test_user_is_not_logged_in() {
+		wp_set_current_user( 0 );
+		$form_data = $this->event_form_handler_factory->future_inactive_event_form_data( 'create_event', $this->now );
+		$response  = $this->event_form_handler->process_form( $form_data );
+
+		$this->assertEquals( 'The user must be logged in.', $response->get_error_message() );
+	}
+
+	public function test_form_name_is_invalid() {
+		$form_data = $this->event_form_handler_factory->future_inactive_event_form_data( 'invalid_form_name', $this->now );
+		$response  = $this->event_form_handler->process_form( $form_data );
+
+		$this->assertEquals( 'Invalid form name.', $response->get_error_message() );
+	}
+
+	public function test_invalid_permissions() {
+		$event_id    = 9999;
+		$form_data_1 = $this->event_form_handler_factory->future_inactive_event_form_data( 'create_event', $this->now );
+		$response_1  = $this->event_form_handler->process_form( $form_data_1 );
+		$this->assertEquals( 'You do not have permissions to create events.', $response_1->get_error_message() );
+
+		$form_data_2 = $this->event_form_handler_factory->future_inactive_event_form_data( 'edit_event', $this->now, $event_id );
+		$response_2  = $this->event_form_handler->process_form( $form_data_2 );
+		$this->assertEquals( 'You do not have permissions to edit this event.', $response_2->get_error_message() );
+
+		$form_data_3 = $this->event_form_handler_factory->future_inactive_event_form_data( 'trash_event', $this->now, $event_id );
+		$response_3  = $this->event_form_handler->process_form( $form_data_3 );
+		$this->assertEquals( 'You do not have permissions to delete this event.', $response_3->get_error_message() );
+	}
+
+	public function test_invalid_nonce() {
+		add_filter( 'gp_translation_events_can_crud_event', '__return_true' );
+		$form_data                 = $this->event_form_handler_factory->future_inactive_event_form_data( 'create_event', $this->now );
+		$form_data['_event_nonce'] = wp_create_nonce( 'invalid_nonce' );
+		$response                  = $this->event_form_handler->process_form( $form_data );
+
+		$this->assertArrayHasKey( 'invalid_nonce', $response->error_data );
+		$this->assertEquals( 'Nonce verification failed.', $response->get_error_message() );
+	}
+
+	/**
+	 * @dataProvider emptyFormDataProvider
+	 */
+	public function test_empty_form_fields( $action, $field, $error_key ) {
+		add_filter( 'gp_translation_events_can_crud_event', '__return_true' );
+		$form_data           = $this->event_form_handler_factory->future_inactive_event_form_data( $action, $this->now );
+		$form_data[ $field ] = '';
+		$response            = $this->event_form_handler->process_form( $form_data );
+
+		$this->assertArrayHasKey( $error_key, $response->error_data );
+	}
+
+	/**
+	 * Data provider for invalid form data test cases.
+	 */
+	public function emptyFormDataProvider() {
+		return array(
+			array( 'create_event', 'event_title', 'invalid_title' ),
+			array( 'create_event', 'event_description', 'invalid_title' ),
+			array( 'create_event', 'event_start', 'invalid_start_date' ),
+			array( 'create_event', 'event_end', 'invalid_end_date' ),
+			array( 'create_event', 'event_timezone', 'invalid_timezone' ),
+			array( 'create_event', 'event_attendance_mode', 'invalid event_attendance_mode' ),
+			array( 'edit_event', 'event_title', 'invalid_title' ),
+			array( 'edit_event', 'event_description', 'invalid_title' ),
+			array( 'edit_event', 'event_start', 'invalid_start_date' ),
+			array( 'edit_event', 'event_end', 'invalid_end_date' ),
+			array( 'edit_event', 'event_timezone', 'invalid_timezone' ),
+			array( 'edit_event', 'event_attendance_mode', 'invalid event_attendance_mode' ),
+		);
+	}
+
+}
diff --git a/tests/lib/event-form-handler-factory.php b/tests/lib/event-form-handler-factory.php
new file mode 100644
index 00000000..abe38222
--- /dev/null
+++ b/tests/lib/event-form-handler-factory.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace Wporg\TranslationEvents\Tests;
+
+use DateTimeImmutable;
+use DateTimeZone;
+
+class Event_Form_Handler_Factory {
+
+	public function future_inactive_event_form_data( $form_name, DateTimeImmutable $now, $event_id = 0 ): array {
+		$timezone              = 'Europe/Lisbon';
+		$event_title           = 'Foo title';
+		$event_description     = 'Foo description';
+		$event_attendance_mode = 'hybrid';
+		$_event_id             = isset( $event_id ) ? $event_id : 0;
+		$event_nonce           = wp_create_nonce( '_event_nonce' );
+
+		return array(
+			'action'                => 'submit_event_ajax',
+			'form_name'             => $form_name,
+			'event_id'              => $_event_id,
+			'event_form_action'     => 'publish',
+			'event_title'           => $event_title,
+			'event_description'     => $event_description,
+			'event_start'           => $now->modify( '+1 month' )->format( 'Y-m-d H:i:s' ),
+			'event_end'             => $now->modify( '+2 month' )->format( 'Y-m-d H:i:s' ),
+			'event_timezone'        => $timezone,
+			'event_attendance_mode' => $event_attendance_mode,
+			'_event_nonce'          => $event_nonce,
+		);
+	}
+}