diff --git tests/phpunit/tests/privacy/wpPrivacySendErasureFulfillmentNotification.php tests/phpunit/tests/privacy/wpPrivacySendErasureFulfillmentNotification.php
new file mode 100644
index 0000000..5164ddf
--- /dev/null
+++ tests/phpunit/tests/privacy/wpPrivacySendErasureFulfillmentNotification.php
@@ -0,0 +1,279 @@
+<?php
+/**
+ * Test cases for the `_wp_privacy_send_erasure_fulfillment_notification()` function.
+ *
+ * @package WordPress
+ * @subpackage UnitTests
+ * @since 4.9.9
+ */
+
+/**
+ * Tests_Privacy_WpPrivacySendErasureFulfillmentNotification class.
+ *
+ * @group privacy
+ * @covers ::_wp_privacy_send_erasure_fulfillment_notification
+ *
+ * @since 4.9.9
+ */
+class Tests_Privacy_WpPrivacySendErasureFulfillmentNotification extends WP_UnitTestCase {
+	/**
+	 * Request ID.
+	 *
+	 * @since 4.9.9
+	 *
+	 * @var int $request_id
+	 */
+	protected static $request_id;
+
+	/**
+	 * Requester Email.
+	 *
+	 * @since 4.9.9
+	 *
+	 * @var string $requester_email
+	 */
+	protected static $requester_email;
+
+	/**
+	 * Create user request fixtures shared by test methods.
+	 *
+	 * @since 4.9.9
+	 *
+	 * @param WP_UnitTest_Factory $factory Factory.
+	 */
+	public static function wpSetUpBeforeClass( $factory ) {
+		self::$requester_email = 'erase-my-data@local.test';
+		self::$request_id      = wp_create_user_request( self::$requester_email, 'erase_personal_data' );
+		wp_update_post(
+			array(
+				'ID'          => self::$request_id,
+				'post_status' => 'request-completed',
+			)
+		);
+	}
+
+	/**
+	 * Reset the mocked PHPMailer instance before each test method.
+	 *
+	 * @since 4.9.9
+	 */
+	public function setUp() {
+		parent::setUp();
+		reset_phpmailer_instance();
+	}
+
+	/**
+	 * Reset the mocked PHPMailer instance after each test method.
+	 *
+	 * @since 4.9.9
+	 */
+	public function tearDown() {
+		reset_phpmailer_instance();
+		parent::tearDown();
+	}
+
+	/**
+	 * The function should send an email when a valid request ID is passed.
+	 *
+	 * @ticket 44234
+	 */
+	public function test_should_send_email_no_privacy_policy() {
+
+		_wp_privacy_send_erasure_fulfillment_notification( self::$request_id );
+
+		$mailer = tests_retrieve_phpmailer_instance();
+		$this->assertContains( self::$requester_email, $mailer->get_recipient( 'to' )->address );
+		$this->assertContains( 'Erasure Request Fulfilled', $mailer->get_sent()->subject );
+		$this->assertContains( 'Your request to erase your personal data', $mailer->get_sent()->body );
+		$this->assertContains( 'has been completed.', $mailer->get_sent()->body );
+		$this->assertContains( wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES ), $mailer->get_sent()->body );
+		$this->assertContains( home_url(), $mailer->get_sent()->body );
+
+		$this->assertNotContains( 'you can also read our privacy policy', $mailer->get_sent()->body );
+		$this->assertTrue( (bool) get_post_meta( self::$request_id, '_wp_user_notified', true ) );
+	}
+
+	/**
+	 * The email should include a link to the site's privacy policy when set.
+	 *
+	 * @ticket 44234
+	 */
+	public function test_should_send_email_with_privacy_policy() {
+		$privacy_policy = $this->factory->post->create(
+			array(
+				'post_type'   => 'page',
+				'title'       => 'Site Privacy Policy',
+				'post_status' => 'publish',
+			)
+		);
+		update_option( 'wp_page_for_privacy_policy', $privacy_policy );
+
+		_wp_privacy_send_erasure_fulfillment_notification( self::$request_id );
+
+		$mailer = tests_retrieve_phpmailer_instance();
+
+		$this->assertContains( self::$requester_email, $mailer->get_recipient( 'to' )->address );
+		$this->assertContains( 'you can also read our privacy policy', $mailer->get_sent()->body );
+		$this->assertContains( get_privacy_policy_url(), $mailer->get_sent()->body );
+		$this->assertTrue( (bool) get_post_meta( self::$request_id, '_wp_user_notified', true ) );
+	}
+
+	/**
+	 * The function should send a fulfillment email only once.
+	 *
+	 * @ticket 44234
+	 */
+	public function test_should_send_email_only_once() {
+		// First function call.
+		_wp_privacy_send_erasure_fulfillment_notification( self::$request_id );
+
+		$mailer = tests_retrieve_phpmailer_instance();
+
+		// Should send an email.
+		$this->assertContains( self::$requester_email, $mailer->get_recipient( 'to' )->address );
+		$this->assertContains( 'Erasure Request Fulfilled', $mailer->get_sent()->subject );
+		$this->assertTrue( (bool) get_post_meta( self::$request_id, '_wp_user_notified', true ) );
+
+		reset_phpmailer_instance();
+
+		// Second function call.
+		_wp_privacy_send_erasure_fulfillment_notification( self::$request_id );
+
+		$mailer = tests_retrieve_phpmailer_instance();
+
+		// Should not send an email.
+		$this->assertEmpty( $mailer->mock_sent );
+		$this->assertTrue( metadata_exists( 'post', self::$request_id, '_wp_user_notified' ) );
+	}
+
+	/**
+	 * The email address of the recipient of the fulfillment notification should be filterable.
+	 *
+	 * @ticket 44234
+	 */
+	public function test_email_address_of_recipient_should_be_filterable() {
+		add_filter( 'user_erasure_fulfillment_email_to', array( $this, 'filter_email_address' ) );
+		_wp_privacy_send_erasure_fulfillment_notification( self::$request_id );
+
+		$mailer = tests_retrieve_phpmailer_instance();
+
+		$this->assertSame( 'modified-' . self::$requester_email, $mailer->get_recipient( 'to' )->address );
+	}
+
+	/**
+	 * Filter callback that modifies the email address of the recipient of the fulfillment notification.
+	 *
+	 * @since 4.9.9
+	 *
+	 * @param string $user_email The email address of the notification recipient.
+	 * @return string $user_email The email address of the notification recipient.
+	 */
+	public function filter_email_address( $user_email ) {
+		return 'modified-' . $user_email;
+	}
+
+	/**
+	 * The email subject of the fulfillment notification should be filterable.
+	 *
+	 * @ticket 44234
+	 */
+	public function test_email_subject_should_be_filterable() {
+		add_filter( 'user_erasure_complete_email_subject', array( $this, 'filter_email_subject' ) );
+		_wp_privacy_send_erasure_fulfillment_notification( self::$request_id );
+
+		$mailer = tests_retrieve_phpmailer_instance();
+
+		$this->assertSame( 'Modified subject', $mailer->get_sent()->subject );
+	}
+
+	/**
+	 * Filter callback that modifies the email subject of the data erasure fulfillment notification.
+	 *
+	 * @since 4.9.9
+	 *
+	 * @param string $subject The email subject.
+	 * @return string $subject The email subject.
+	 */
+	public function filter_email_subject( $subject ) {
+		return 'Modified subject';
+	}
+
+	/**
+	 * The email body text of the fulfillment notification should be filterable.
+	 *
+	 * @ticket 44234
+	 */
+	public function test_email_body_text_should_be_filterable() {
+		add_filter( 'user_confirmed_action_email_content', array( $this, 'filter_email_body_text' ) );
+		_wp_privacy_send_erasure_fulfillment_notification( self::$request_id );
+
+		$mailer = tests_retrieve_phpmailer_instance();
+
+		$this->assertSame( 'Modified text', trim( $mailer->get_sent()->body ) );
+	}
+
+	/**
+	 * Filter callback that modifies the email body text of the data erasure fulfillment notification.
+	 *
+	 * @since 4.9.9
+	 *
+	 * @param string $email_text Text in the email.
+	 * @return string $email_text Text in the email.
+	 */
+	public function filter_email_body_text( $email_text ) {
+		return 'Modified text';
+	}
+
+	/**
+	 * The function should not send an email when the request ID does not exist.
+	 *
+	 * @ticket 44234
+	 */
+	public function test_should_not_send_email_when_passed_invalid_request_id() {
+		_wp_privacy_send_erasure_fulfillment_notification( 1234567890 );
+
+		$mailer = tests_retrieve_phpmailer_instance();
+
+		$this->assertEmpty( $mailer->mock_sent );
+	}
+
+	/**
+	 * The function should not send an email when the ID passed does not correspond to a user request.
+	 *
+	 * @ticket 44234
+	 */
+	public function test_should_not_send_email_when_not_user_request() {
+		$post_id = $this->factory->post->create(
+			array(
+				'post_type' => 'post', // Should be 'user_request'.
+			)
+		);
+
+		_wp_privacy_send_erasure_fulfillment_notification( $post_id );
+		$mailer = tests_retrieve_phpmailer_instance();
+
+		$this->assertEmpty( $mailer->mock_sent );
+	}
+
+	/**
+	 * The function should not send an email when the request is not completed.
+	 *
+	 * @ticket 44234
+	 */
+	public function test_should_not_send_email_when_request_not_completed() {
+		wp_update_post(
+			array(
+				'ID'          => self::$request_id,
+				'post_status' => 'request-confirmed', // Should be 'request-completed'.
+			)
+		);
+
+		_wp_privacy_send_erasure_fulfillment_notification( self::$request_id );
+
+		$mailer = tests_retrieve_phpmailer_instance();
+
+		$this->assertEmpty( $mailer->mock_sent );
+		$this->assertFalse( metadata_exists( 'post', self::$request_id, '_wp_user_notified' ) );
+	}
+
+}