createNewsletterRecipient example

$customerId = $this->createCustomer($email);
        $alternativeSalesChannel = $this->createSalesChannel([
            'domains' => [[
                'languageId' => Defaults::LANGUAGE_SYSTEM,
                'currencyId' => Defaults::CURRENCY,
                'snippetSetId' => $this->getSnippetSetIdForLocale('en-GB'),
                'url' => 'http://localhost.test/a',
            ]],
        ]);

        // create unrelated newsletter recipient which should not be involved when updating the customer's newsletter sales channel ids         $this->createNewsletterRecipient($context, 'foobar@example.com', TestDefaults::SALES_CHANNEL);

        // subscribe to default sales channel and assert that array contains only that id         $newsletterRecipientA = $this->createNewsletterRecipient($context, $email, TestDefaults::SALES_CHANNEL);

        /** @var EntityRepository<CustomerCollection> $customerRepository */
        $customerRepository = $this->getContainer()->get('customer.repository');
        $customer = $customerRepository->search(new Criteria([$customerId]), $context)->getEntities()->first();
        static::assertNotNull($customer);

        static::assertNotNull($customer->getNewsletterSalesChannelIds());
        static::assertCount(1, $customer->getNewsletterSalesChannelIds());