diff --git a/mailpoet/tests/integration/API/JSON/v1/FeatureFlagsTest.php b/mailpoet/tests/integration/API/JSON/v1/FeatureFlagsTest.php
index 9187fda34d..52dc034465 100644
--- a/mailpoet/tests/integration/API/JSON/v1/FeatureFlagsTest.php
+++ b/mailpoet/tests/integration/API/JSON/v1/FeatureFlagsTest.php
@@ -103,7 +103,7 @@ class FeatureFlagsTest extends \MailPoetTest {
     ]);
 
     $endpoint = $this->createEndpointWithFeatureDefaults([]);
-    expect($endpoint->getAll()->data)->isEmpty();
+    verify($endpoint->getAll()->data)->empty();
   }
 
   public function testItDoesNotSaveUnknownFlag() {
diff --git a/mailpoet/tests/integration/API/JSON/v1/FormsTest.php b/mailpoet/tests/integration/API/JSON/v1/FormsTest.php
index d9a483e527..87a3ec86a9 100644
--- a/mailpoet/tests/integration/API/JSON/v1/FormsTest.php
+++ b/mailpoet/tests/integration/API/JSON/v1/FormsTest.php
@@ -229,7 +229,7 @@ class FormsTest extends \MailPoetTest {
     $response = $this->endpoint->restore(['id' => 'Invalid ID']);
     verify($response->errors[0]['error'])->equals('not_found');
     verify($response->status)->equals(APIResponse::STATUS_NOT_FOUND);
-    expect($response->meta)->isEmpty();
+    verify($response->meta)->empty();
   }
 
   public function testItCanTrashAForm() {
@@ -246,12 +246,12 @@ class FormsTest extends \MailPoetTest {
     $response = $this->endpoint->trash(['id' => 'Invalid ID']);
     verify($response->errors[0]['error'])->equals('not_found');
     verify($response->status)->equals(APIResponse::STATUS_NOT_FOUND);
-    expect($response->meta)->isEmpty();
+    verify($response->meta)->empty();
   }
 
   public function testItCanDeleteAForm() {
     $response = $this->endpoint->delete(['id' => $this->form3->getId()]);
-    expect($response->data)->isEmpty();
+    verify($response->data)->empty();
     verify($response->status)->equals(APIResponse::STATUS_OK);
     verify($response->meta['count'])->equals(1);
   }
@@ -260,7 +260,7 @@ class FormsTest extends \MailPoetTest {
     $response = $this->endpoint->delete(['id' => 'Invalid ID']);
     verify($response->errors[0]['error'])->equals('not_found');
     verify($response->status)->equals(APIResponse::STATUS_NOT_FOUND);
-    expect($response->meta)->isEmpty();
+    verify($response->meta)->empty();
   }
 
   public function testItCanDuplicateAForm() {
diff --git a/mailpoet/tests/integration/API/JSON/v1/NewslettersTest.php b/mailpoet/tests/integration/API/JSON/v1/NewslettersTest.php
index 1f886b4084..816e19af8d 100644
--- a/mailpoet/tests/integration/API/JSON/v1/NewslettersTest.php
+++ b/mailpoet/tests/integration/API/JSON/v1/NewslettersTest.php
@@ -348,7 +348,7 @@ class NewslettersTest extends \MailPoetTest {
 
   public function testItCanDeleteANewsletter() {
     $response = $this->endpoint->delete(['id' => $this->newsletter->getId()]);
-    expect($response->data)->isEmpty();
+    verify($response->data)->empty();
     verify($response->status)->equals(APIResponse::STATUS_OK);
     verify($response->meta['count'])->equals(1);
   }
diff --git a/mailpoet/tests/integration/API/JSON/v1/SegmentsTest.php b/mailpoet/tests/integration/API/JSON/v1/SegmentsTest.php
index 0908c177f1..abd31ed3f3 100644
--- a/mailpoet/tests/integration/API/JSON/v1/SegmentsTest.php
+++ b/mailpoet/tests/integration/API/JSON/v1/SegmentsTest.php
@@ -203,7 +203,7 @@ class SegmentsTest extends \MailPoetTest {
 
   public function testItCanDeleteASegment() {
     $response = $this->endpoint->delete(['id' => $this->segment3->getId()]);
-    expect($response->data)->isEmpty();
+    verify($response->data)->empty();
     verify($response->status)->equals(APIResponse::STATUS_OK);
     verify($response->meta['count'])->equals(1);
   }
diff --git a/mailpoet/tests/integration/API/JSON/v1/SettingsTest.php b/mailpoet/tests/integration/API/JSON/v1/SettingsTest.php
index 8e309bec20..3c185daa60 100644
--- a/mailpoet/tests/integration/API/JSON/v1/SettingsTest.php
+++ b/mailpoet/tests/integration/API/JSON/v1/SettingsTest.php
@@ -269,7 +269,7 @@ class SettingsTest extends \MailPoetTest {
 
     $this->settings->resetCache();
     verify($this->settings->get('sender')['address'])->equals('johndoeexampletestnonexistinghopefullyfreemail@gmail.com');
-    expect($this->settings->get('reply_to'))->isEmpty();
+    verify($this->settings->get('reply_to'))->empty();
   }
 
   public function testItDeactivatesReEngagementEmailsIfTrackingDisabled(): void {
diff --git a/mailpoet/tests/integration/API/JSON/v1/SubscribersTest.php b/mailpoet/tests/integration/API/JSON/v1/SubscribersTest.php
index ab5f95f57d..2d0dd412ac 100644
--- a/mailpoet/tests/integration/API/JSON/v1/SubscribersTest.php
+++ b/mailpoet/tests/integration/API/JSON/v1/SubscribersTest.php
@@ -350,7 +350,7 @@ class SubscribersTest extends \MailPoetTest {
 
   public function testItCanDeleteASubscriber() {
     $response = $this->endpoint->delete(['id' => $this->subscriber1->getId()]);
-    expect($response->data)->isEmpty();
+    verify($response->data)->empty();
     verify($response->status)->equals(APIResponse::STATUS_OK);
     verify($response->meta['count'])->equals(1);
   }
@@ -604,7 +604,7 @@ class SubscribersTest extends \MailPoetTest {
       'action' => 'delete',
     ]);
     verify($response->status)->equals(APIResponse::STATUS_OK);
-    expect($response->data)->isEmpty();
+    verify($response->data)->empty();
     verify($response->meta['count'])->equals(count($selectionIds));
 
     $this->entityManager->clear();
@@ -938,7 +938,7 @@ class SubscribersTest extends \MailPoetTest {
 
     // welcome notification is created only for segment #1
     $this->endpoint->save($subscriberData);
-    expect($this->sendingQueuesRepository->findAll())->isEmpty();
+    verify($this->sendingQueuesRepository->findAll())->empty();
 
     $subscriberData['segments'] = [$this->segment1->getId()];
     $this->endpoint->save($subscriberData);
diff --git a/mailpoet/tests/integration/AutomaticEmails/WooCommerce/Events/FirstPurchaseTest.php b/mailpoet/tests/integration/AutomaticEmails/WooCommerce/Events/FirstPurchaseTest.php
index 03c0661dc0..6779c45f8d 100644
--- a/mailpoet/tests/integration/AutomaticEmails/WooCommerce/Events/FirstPurchaseTest.php
+++ b/mailpoet/tests/integration/AutomaticEmails/WooCommerce/Events/FirstPurchaseTest.php
@@ -157,7 +157,7 @@ class FirstPurchaseTest extends \MailPoetTest {
     ]);
     $event = new FirstPurchase($helper);
     $result = $event->scheduleEmailWhenOrderIsPlaced(12);
-    expect($result)->isEmpty();
+    verify($result)->empty();
   }
 
   public function testItDoesNotScheduleEmailWhenCustomerEmailIsEmpty() {
@@ -173,7 +173,7 @@ class FirstPurchaseTest extends \MailPoetTest {
     ]);
     $event = new FirstPurchase($helper);
     $result = $event->scheduleEmailWhenOrderIsPlaced(12);
-    expect($result)->isEmpty();
+    verify($result)->empty();
   }
 
   public function testItDoesNotScheduleEmailWhenItIsNotCustomersFirstPurchase() {
@@ -185,7 +185,7 @@ class FirstPurchaseTest extends \MailPoetTest {
       'getCustomerOrderCount' => 2,
     ]);
     $result = $event->scheduleEmailWhenOrderIsPlaced(12);
-    expect($result)->isEmpty();
+    verify($result)->empty();
   }
 
   public function testItDoesNotScheduleEmailWhenCustomerIsNotAWCSegmentSubscriber() {
@@ -216,7 +216,7 @@ class FirstPurchaseTest extends \MailPoetTest {
 
     $event = new FirstPurchase($helper);
     $result = $event->scheduleEmailWhenOrderIsPlaced(12);
-    expect($result)->isEmpty();
+    verify($result)->empty();
   }
 
   public function testItScheduleEmailForGuestCustomer() {
@@ -240,7 +240,7 @@ class FirstPurchaseTest extends \MailPoetTest {
 
     $event = new FirstPurchase($this->wooCommerceHelper);
     $result = $event->scheduleEmailWhenOrderIsPlaced($order->get_id());
-    expect($result)->isEmpty();
+    verify($result)->empty();
 
     $sendingQueue = $this->sendingQueueRepository->findOneBy(['newsletter' => $newsletter]);
     $this->assertInstanceOf(SendingQueueEntity::class, $sendingQueue);
diff --git a/mailpoet/tests/integration/AutomaticEmails/WooCommerce/Events/PurchasedProductTest.php b/mailpoet/tests/integration/AutomaticEmails/WooCommerce/Events/PurchasedProductTest.php
index 6ee41b6991..db5fd9181f 100644
--- a/mailpoet/tests/integration/AutomaticEmails/WooCommerce/Events/PurchasedProductTest.php
+++ b/mailpoet/tests/integration/AutomaticEmails/WooCommerce/Events/PurchasedProductTest.php
@@ -53,7 +53,7 @@ class PurchasedProductTest extends \MailPoetTest {
     ]);
     $event = new PurchasedProduct($helper);
     $result = $event->scheduleEmailWhenProductIsPurchased(12);
-    expect($result)->isEmpty();
+    verify($result)->empty();
   }
 
   public function testItDoesNotScheduleEmailWhenCustomerEmailIsEmpty() {
@@ -70,7 +70,7 @@ class PurchasedProductTest extends \MailPoetTest {
     $event = new PurchasedProduct($helper);
 
     $result = $event->scheduleEmailWhenProductIsPurchased(12);
-    expect($result)->isEmpty();
+    verify($result)->empty();
   }
 
   public function testItDoesNotScheduleEmailWhenCustomerIsNotAWCSegmentSubscriber() {
@@ -97,7 +97,7 @@ class PurchasedProductTest extends \MailPoetTest {
     $event = new PurchasedProduct($helper);
 
     $result = $event->scheduleEmailWhenProductIsPurchased(12);
-    expect($result)->isEmpty();
+    verify($result)->empty();
   }
 
   public function testItDoesNotScheduleEmailWhenAlreadySent() {
@@ -139,7 +139,7 @@ class PurchasedProductTest extends \MailPoetTest {
     $email = $this->createEmailTriggeredByProductIds([2000, 3000]);
     $event = $this->createOrderEvent($subscriber, [1000]);
     $scheduledTask = $this->triggerEmailForState('completed', $email, $event);
-    expect($scheduledTask)->isEmpty();
+    verify($scheduledTask)->empty();
   }
 
   public function testItSchedulesEmailForProcessingOrder() {
diff --git a/mailpoet/tests/integration/Config/TranslationUpdaterTest.php b/mailpoet/tests/integration/Config/TranslationUpdaterTest.php
index 81f60e6bfb..2ec9bec02c 100644
--- a/mailpoet/tests/integration/Config/TranslationUpdaterTest.php
+++ b/mailpoet/tests/integration/Config/TranslationUpdaterTest.php
@@ -169,7 +169,7 @@ class TranslationUpdaterTest extends \MailPoetTest {
       ]
     );
     $result = $updater->checkForTranslations($updateTransient);
-    expect($result->translations)->isEmpty();
+    verify($result->translations)->empty();
   }
 
   public function testItDoesNotOverrideNewerVersionInCaseItWasInstalledFromDotOrg(): void {
diff --git a/mailpoet/tests/integration/Cron/CronWorkerRunnerTest.php b/mailpoet/tests/integration/Cron/CronWorkerRunnerTest.php
index 7430c8dce0..c7b6ee6548 100644
--- a/mailpoet/tests/integration/Cron/CronWorkerRunnerTest.php
+++ b/mailpoet/tests/integration/Cron/CronWorkerRunnerTest.php
@@ -143,7 +143,7 @@ class CronWorkerRunnerTest extends \MailPoetTest {
     $this->assertInstanceOf(ScheduledTaskEntity::class, $task);
     expect($task->getScheduledAt())->greaterThan($scheduledAt);
     verify($task->getStatus())->same(ScheduledTaskEntity::STATUS_SCHEDULED);
-    expect($task->getInProgress())->isEmpty();
+    verify($task->getInProgress())->empty();
 
     // reset the state of the updatedAt field. this is needed to reset the state of TimestampListener::now otherwise it will impact other tests.
     // this code can be removed once https://mailpoet.atlassian.net/browse/MAILPOET-3870 is fixed.
@@ -171,7 +171,7 @@ class CronWorkerRunnerTest extends \MailPoetTest {
       expect($task->getScheduledAt())->greaterThan($scheduledAt);
       verify($task->getStatus())->same(ScheduledTaskEntity::STATUS_SCHEDULED);
       verify($task->getRescheduleCount())->equals(1);
-      expect($task->getInProgress())->isEmpty();
+      verify($task->getInProgress())->empty();
     }
   }
 
diff --git a/mailpoet/tests/integration/Cron/Triggers/WordPressTest.php b/mailpoet/tests/integration/Cron/Triggers/WordPressTest.php
index dcc7bd6a71..b361abd01f 100644
--- a/mailpoet/tests/integration/Cron/Triggers/WordPressTest.php
+++ b/mailpoet/tests/integration/Cron/Triggers/WordPressTest.php
@@ -89,7 +89,7 @@ class WordPressTest extends \MailPoetTest {
     $this->settings->set(WordPress::LAST_RUN_AT_SETTING, $currentTime);
     $this->addQueue(SendingQueueEntity::STATUS_SCHEDULED);
     WordPress::resetRunInterval();
-    expect($this->settings->get(WordPress::LAST_RUN_AT_SETTING))->isEmpty();
+    verify($this->settings->get(WordPress::LAST_RUN_AT_SETTING))->empty();
     verify($this->wordpressTrigger->run())->notEmpty();
   }
 
diff --git a/mailpoet/tests/integration/Cron/Workers/BounceTest.php b/mailpoet/tests/integration/Cron/Workers/BounceTest.php
index 22125326de..12b9619797 100644
--- a/mailpoet/tests/integration/Cron/Workers/BounceTest.php
+++ b/mailpoet/tests/integration/Cron/Workers/BounceTest.php
@@ -107,7 +107,7 @@ class BounceTest extends \MailPoetTest {
     $this->truncateEntity(SubscriberEntity::class);
     $task = $this->createScheduledTask();
     $this->worker->prepareTaskStrategy($task, microtime(true));
-    expect($this->scheduledTaskSubscribersRepository->findBy(['task' => $task]))->isEmpty();
+    verify($this->scheduledTaskSubscribersRepository->findBy(['task' => $task]))->empty();
   }
 
   public function testItPreparesTask() {
@@ -134,7 +134,7 @@ class BounceTest extends \MailPoetTest {
     // process - no subscribers found, ScheduledTaskSubscriber will be cleaned up
     $task = $this->createScheduledTask();
     $this->worker->processTaskStrategy($task, microtime(true));
-    expect($this->scheduledTaskSubscribersRepository->findBy(['task' => $task]))->isEmpty();
+    verify($this->scheduledTaskSubscribersRepository->findBy(['task' => $task]))->empty();
   }
 
   public function testItProcessesTask() {
diff --git a/mailpoet/tests/integration/Cron/Workers/SchedulerTest.php b/mailpoet/tests/integration/Cron/Workers/SchedulerTest.php
index 3eb14ea67d..4799ee4be2 100644
--- a/mailpoet/tests/integration/Cron/Workers/SchedulerTest.php
+++ b/mailpoet/tests/integration/Cron/Workers/SchedulerTest.php
@@ -125,7 +125,7 @@ class SchedulerTest extends \MailPoetTest {
 
   public function testItCanGetScheduledQueues() {
     $scheduler = $this->diContainer->get(Scheduler::class);
-    expect($scheduler->getScheduledSendingTasks())->isEmpty();
+    verify($scheduler->getScheduledSendingTasks())->empty();
     $queue = SendingTask::create();
     $queue->newsletterId = 1;
     $queue->status = SendingQueueEntity::STATUS_SCHEDULED;
@@ -148,7 +148,7 @@ class SchedulerTest extends \MailPoetTest {
 
     // ensure that notification history does not exist
     $notificationHistory = $this->newslettersRepository->findOneBy(['parent' => $newsletter, 'type' => NewsletterEntity::TYPE_NOTIFICATION_HISTORY]);
-    expect($notificationHistory)->isEmpty();
+    verify($notificationHistory)->empty();
 
     // create notification history and ensure that it exists
     $scheduler = $this->getScheduler();
diff --git a/mailpoet/tests/integration/Cron/Workers/SimpleWorkerTest.php b/mailpoet/tests/integration/Cron/Workers/SimpleWorkerTest.php
index 2b932b42c9..c2b591fe95 100644
--- a/mailpoet/tests/integration/Cron/Workers/SimpleWorkerTest.php
+++ b/mailpoet/tests/integration/Cron/Workers/SimpleWorkerTest.php
@@ -42,7 +42,7 @@ class SimpleWorkerTest extends \MailPoetTest {
   }
 
   public function testItSchedulesTask() {
-    expect($this->scheduledTasksRepository->findBy(['type' => MockSimpleWorker::TASK_TYPE]))->isEmpty();
+    verify($this->scheduledTasksRepository->findBy(['type' => MockSimpleWorker::TASK_TYPE]))->empty();
     (new MockSimpleWorker())->schedule();
     verify($this->scheduledTasksRepository->findBy(['type' => MockSimpleWorker::TASK_TYPE]))->notEmpty();
   }
diff --git a/mailpoet/tests/integration/Cron/Workers/WooCommerceOrdersTest.php b/mailpoet/tests/integration/Cron/Workers/WooCommerceOrdersTest.php
index 4a6602f050..e84c1605ed 100644
--- a/mailpoet/tests/integration/Cron/Workers/WooCommerceOrdersTest.php
+++ b/mailpoet/tests/integration/Cron/Workers/WooCommerceOrdersTest.php
@@ -59,7 +59,7 @@ class WooCommerceOrdersTest extends \MailPoetTest {
 
     $this->cronWorkerRunner->run($this->worker);
     $tasks = $this->scheduledTaskRepository->findBy(['type' => WooCommercePastOrders::TASK_TYPE]);
-    expect($tasks)->isEmpty();
+    verify($tasks)->empty();
   }
 
   public function testItRunsIfWooCommerceIsEnabled() {
diff --git a/mailpoet/tests/integration/Logging/LogHandlerTest.php b/mailpoet/tests/integration/Logging/LogHandlerTest.php
index 30dbba3e9a..b66105f137 100644
--- a/mailpoet/tests/integration/Logging/LogHandlerTest.php
+++ b/mailpoet/tests/integration/Logging/LogHandlerTest.php
@@ -75,7 +75,7 @@ class LogHandlerTest extends \MailPoetTest {
     ]);
 
     $log = $this->repository->findBy(['name' => 'old name']);
-    expect($log)->isEmpty();
+    verify($log)->empty();
   }
 
   public function testItNotPurgesOldLogs() {
diff --git a/mailpoet/tests/integration/Mailer/Methods/SMTPTest.php b/mailpoet/tests/integration/Mailer/Methods/SMTPTest.php
index bda9080f70..ca56b93991 100644
--- a/mailpoet/tests/integration/Mailer/Methods/SMTPTest.php
+++ b/mailpoet/tests/integration/Mailer/Methods/SMTPTest.php
@@ -141,7 +141,7 @@ class SMTPTest extends \MailPoetTest {
 
   public function testItAppliesSMTPOptionsFilter() {
     $mailer = $this->mailer->buildMailer();
-    expect($mailer->SMTPOptions)->isEmpty();
+    verify($mailer->SMTPOptions)->empty();
     (new WPFunctions)->addFilter(
       'mailpoet_mailer_smtp_options',
       function() {
diff --git a/mailpoet/tests/integration/Models/NewsletterTest.php b/mailpoet/tests/integration/Models/NewsletterTest.php
index 3cd2daa7ca..b9f2b25d85 100644
--- a/mailpoet/tests/integration/Models/NewsletterTest.php
+++ b/mailpoet/tests/integration/Models/NewsletterTest.php
@@ -237,10 +237,10 @@ class NewsletterTest extends \MailPoetTest {
     }
 
     Newsletter::filter('bulkTrash');
-    expect(Newsletter::whereNull('deleted_at')->findArray())->isEmpty();
+    verify(Newsletter::whereNull('deleted_at')->findArray())->empty();
 
     Newsletter::filter('bulkRestore');
-    expect(Newsletter::whereNotNull('deleted_at')->findArray())->isEmpty();
+    verify(Newsletter::whereNotNull('deleted_at')->findArray())->empty();
   }
 
   public function testItDeletesSegmentAndQueueAssociationsWhenNewsletterIsDeleted() {
@@ -260,9 +260,9 @@ class NewsletterTest extends \MailPoetTest {
 
     // delete newsletter and check that relations no longer exist
     $newsletter->delete();
-    expect(SendingQueue::where('newsletter_id', $newsletter->id)->findArray())->isEmpty();
+    verify(SendingQueue::where('newsletter_id', $newsletter->id)->findArray())->empty();
     $newsletterSegments = NewsletterSegment::where('newsletter_id', $newsletter->id)->findArray();
-    expect($newsletterSegments)->isEmpty();
+    verify($newsletterSegments)->empty();
   }
 
   public function testItDeletesChildrenSegmentAndQueueAssociationsWhenParentNewsletterIsDeleted() {
@@ -415,7 +415,7 @@ class NewsletterTest extends \MailPoetTest {
     $this->newsletterOptionFactory->create($newsletterEntity, 'meta', json_encode($meta));
 
     // by default meta option does not exist on newsletter object
-    expect($newsletter->getMeta())->isEmpty();
+    verify($newsletter->getMeta())->empty();
 
     // if meta option exists, it should be returned as an array
     $newsletter = Newsletter::filter('filterWithOptions', Newsletter::TYPE_AUTOMATIC)->findOne($newsletter->id);
diff --git a/mailpoet/tests/integration/Models/SubscriberCustomFieldTest.php b/mailpoet/tests/integration/Models/SubscriberCustomFieldTest.php
index c53ab3c1f4..7b01e49332 100644
--- a/mailpoet/tests/integration/Models/SubscriberCustomFieldTest.php
+++ b/mailpoet/tests/integration/Models/SubscriberCustomFieldTest.php
@@ -64,7 +64,7 @@ class SubscriberCustomFieldTest extends \MailPoetTest {
       ]
     );
     $records = SubscriberCustomField::findArray();
-    expect($records)->isEmpty();
+    verify($records)->empty();
   }
 
   public function testItCanDeleteSubscriberRelations() {
diff --git a/mailpoet/tests/integration/Models/SubscriberSegmentTest.php b/mailpoet/tests/integration/Models/SubscriberSegmentTest.php
index 7aa6a97a0a..40818442db 100644
--- a/mailpoet/tests/integration/Models/SubscriberSegmentTest.php
+++ b/mailpoet/tests/integration/Models/SubscriberSegmentTest.php
@@ -155,7 +155,7 @@ class SubscriberSegmentTest extends \MailPoetTest {
     verify($result)->true();
 
     $subscribedSegments = $this->subscriber->segments()->findArray();
-    expect($subscribedSegments)->isEmpty();
+    verify($subscribedSegments)->empty();
 
     // the relations still exist but now have a status of "unsubscribed"
     $subscriptionsCount = SubscriberSegment::where(
diff --git a/mailpoet/tests/integration/Models/SubscriberTest.php b/mailpoet/tests/integration/Models/SubscriberTest.php
index 45235128b7..f472a0a3f3 100644
--- a/mailpoet/tests/integration/Models/SubscriberTest.php
+++ b/mailpoet/tests/integration/Models/SubscriberTest.php
@@ -440,7 +440,7 @@ class SubscriberTest extends \MailPoetTest {
     $record->lastName = 'Mailer';
     $result = Subscriber::createOrUpdate($record->asArray());
     verify($result)->notEquals(false);
-    expect($result->getValidationErrors())->isEmpty();
+    verify($result->getValidationErrors())->empty();
     $record = Subscriber::where('email', $data['email'])
       ->findOne();
     verify($record->lastName)->equals('Mailer');
@@ -855,8 +855,8 @@ class SubscriberTest extends \MailPoetTest {
       ]
     );
     verify($result->getErrors())->false();
-    expect($result->firstName)->isEmpty();
-    expect($result->lastName)->isEmpty();
+    verify($result->firstName)->empty();
+    verify($result->lastName)->empty();
     verify($result->status)->equals(Subscriber::STATUS_UNCONFIRMED);
   }
 
diff --git a/mailpoet/tests/integration/Newsletter/Scheduler/SchedulerTest.php b/mailpoet/tests/integration/Newsletter/Scheduler/SchedulerTest.php
index eed167c4f4..0b60bb626d 100644
--- a/mailpoet/tests/integration/Newsletter/Scheduler/SchedulerTest.php
+++ b/mailpoet/tests/integration/Newsletter/Scheduler/SchedulerTest.php
@@ -26,7 +26,7 @@ class SchedulerTest extends \MailPoetTest {
     $newsletterFactory->withWelcomeTypeForSegment()->withActiveStatus()->create();
 
     // no newsletters with type "notification" should be found
-    expect($this->testee->getNewsletters(NewsletterEntity::TYPE_NOTIFICATION))->isEmpty();
+    verify($this->testee->getNewsletters(NewsletterEntity::TYPE_NOTIFICATION))->empty();
 
     // one newsletter with type "welcome" should be found
     expect($this->testee->getNewsletters(NewsletterEntity::TYPE_WELCOME))->count(1);
@@ -35,7 +35,7 @@ class SchedulerTest extends \MailPoetTest {
     $newsletter = $newsletterFactory->withAutomaticType()->withActiveStatus()->create();
     $newsletterOptionFactory->create($newsletter, 'group', 'test');
 
-    expect($this->testee->getNewsletters(NewsletterEntity::TYPE_WELCOME, 'group_does_not_exist'))->isEmpty();
+    verify($this->testee->getNewsletters(NewsletterEntity::TYPE_WELCOME, 'group_does_not_exist'))->empty();
     expect($this->testee->getNewsletters(NewsletterEntity::TYPE_AUTOMATIC, 'test'))->count(1);
   }
 
diff --git a/mailpoet/tests/integration/Newsletter/ShortcodesTest.php b/mailpoet/tests/integration/Newsletter/ShortcodesTest.php
index 591bf08e58..e8f72358c2 100644
--- a/mailpoet/tests/integration/Newsletter/ShortcodesTest.php
+++ b/mailpoet/tests/integration/Newsletter/ShortcodesTest.php
@@ -93,10 +93,10 @@ class ShortcodesTest extends \MailPoetTest {
     verify($details['argument_value'])->equals('default_value');
     $content = '[category:action|default]';
     $details = $shortcodesObject->match($content);
-    expect($details)->isEmpty();
+    verify($details)->empty();
     $content = '[category|default:default_value]';
     $details = $shortcodesObject->match($content);
-    expect($details)->isEmpty();
+    verify($details)->empty();
   }
 
   public function testItCanProcessCustomShortcodes() {
diff --git a/mailpoet/tests/integration/Segments/DynamicSegments/Filters/SubscriberSubscribedViaFormTest.php b/mailpoet/tests/integration/Segments/DynamicSegments/Filters/SubscriberSubscribedViaFormTest.php
index c632a1520a..e157c8ea1d 100644
--- a/mailpoet/tests/integration/Segments/DynamicSegments/Filters/SubscriberSubscribedViaFormTest.php
+++ b/mailpoet/tests/integration/Segments/DynamicSegments/Filters/SubscriberSubscribedViaFormTest.php
@@ -35,7 +35,7 @@ class SubscriberSubscribedViaFormTest extends \MailPoetTest {
     $subscriber = (new Subscriber())->withEmail('subscriber1@example.com')->create();
     (new StatisticsForms($form, $subscriber))->create();
     $matching = $this->getMatchingEmails('any', [$form->getId() + 1]);
-    expect($matching)->isEmpty();
+    verify($matching)->empty();
   }
 
   public function testItWorksWithMultipleForms(): void {
diff --git a/mailpoet/tests/integration/Segments/WPTest.php b/mailpoet/tests/integration/Segments/WPTest.php
index fda8f20ba1..772cb23dbd 100644
--- a/mailpoet/tests/integration/Segments/WPTest.php
+++ b/mailpoet/tests/integration/Segments/WPTest.php
@@ -222,7 +222,7 @@ class WPTest extends \MailPoetTest {
     $this->updateWPUserEmail($id, '');
     $this->wpSegment->synchronizeUsers();
     $subscriber = Subscriber::where('wp_user_id', $id)->findOne();
-    expect($subscriber)->isEmpty();
+    verify($subscriber)->empty();
     $this->deleteWPUser($id);
   }
 
@@ -412,7 +412,7 @@ class WPTest extends \MailPoetTest {
     verify($dbSubscriber)->notEmpty();
     $this->wpSegment->synchronizeUsers();
     $dbSubscriber = Subscriber::findOne($subscriber->id);
-    expect($dbSubscriber)->isEmpty();
+    verify($dbSubscriber)->empty();
   }
 
   public function testItAddsNewUserToDisabledWpSegmentAsUnconfirmedAndTrashed(): void {
diff --git a/mailpoet/tests/integration/Segments/WooCommerceTest.php b/mailpoet/tests/integration/Segments/WooCommerceTest.php
index 13e1aa41fd..b93dc59a7d 100644
--- a/mailpoet/tests/integration/Segments/WooCommerceTest.php
+++ b/mailpoet/tests/integration/Segments/WooCommerceTest.php
@@ -126,7 +126,7 @@ class WooCommerceTest extends \MailPoetTest {
     $guest = $this->insertGuestCustomer();
     $this->wooCommerceSegment->synchronizeGuestCustomer($guest['order_id']);
     $subscribers = $this->getWCSubscribersByEmails([$guest['email']]);
-    expect($subscribers)->isEmpty();
+    verify($subscribers)->empty();
     $subscriber = $this->subscribersRepository->findOneBy(['email' => $guest['email']]);
     $this->assertInstanceOf(SubscriberEntity::class, $subscriber);
     verify($subscriber->getFirstName())->equals($guest['first_name']);
@@ -142,7 +142,7 @@ class WooCommerceTest extends \MailPoetTest {
     $guest = $this->insertGuestCustomer();
     $this->wooCommerceSegment->synchronizeGuestCustomer($guest['order_id']);
     $subscribers = $this->getWCSubscribersByEmails([$guest['email']]);
-    expect($subscribers)->isEmpty();
+    verify($subscribers)->empty();
     $subscriber = $this->subscribersRepository->findOneBy(['email' => $guest['email']]);
     $this->assertInstanceOf(SubscriberEntity::class, $subscriber);
     verify($subscriber->getFirstName())->equals($guest['first_name']);
@@ -158,7 +158,7 @@ class WooCommerceTest extends \MailPoetTest {
     $guest = $this->insertGuestCustomer();
     $this->wooCommerceSegment->synchronizeGuestCustomer($guest['order_id']);
     $subscribers = $this->getWCSubscribersByEmails([$guest['email']]);
-    expect($subscribers)->isEmpty();
+    verify($subscribers)->empty();
     $subscriber = $this->subscribersRepository->findOneBy(['email' => $guest['email']]);
     $this->assertInstanceOf(SubscriberEntity::class, $subscriber);
     verify($subscriber->getFirstName())->equals($guest['first_name']);
@@ -271,7 +271,7 @@ class WooCommerceTest extends \MailPoetTest {
     update_post_meta($guest['order_id'], '_billing_email', '');
     $this->synchronizeAllCustomers();
     $subscriber = $this->subscribersRepository->findOneBy(['email' => '']);
-    expect($subscriber)->isEmpty();
+    verify($subscriber)->empty();
     $this->tester->deleteTestWooOrders();
   }
 
@@ -281,7 +281,7 @@ class WooCommerceTest extends \MailPoetTest {
     update_post_meta($guest['order_id'], '_billing_email', $invalidEmail);
     $this->synchronizeAllCustomers();
     $subscriber = $this->subscribersRepository->findOneBy(['email' => $invalidEmail]);
-    expect($subscriber)->isEmpty();
+    verify($subscriber)->empty();
     $this->tester->deleteTestWooOrders();
   }
 
@@ -442,7 +442,7 @@ class WooCommerceTest extends \MailPoetTest {
     verify($this->subscriberSegmentsRepository->findOneById($association->getId()))->notEmpty();
     $this->synchronizeAllCustomers();
     $this->entityManager->clear();
-    expect($this->subscriberSegmentsRepository->findOneById($association->getId()))->isEmpty();
+    verify($this->subscriberSegmentsRepository->findOneById($association->getId()))->empty();
   }
 
   public function testItUnsubscribesSubscribersWithoutEmailFromWCSegment(): void {
@@ -460,7 +460,7 @@ class WooCommerceTest extends \MailPoetTest {
     verify($this->subscriberSegmentsRepository->findOneById($association->getId()))->notEmpty();
     $this->entityManager->clear();
     $this->synchronizeAllCustomers();
-    expect($this->subscriberSegmentsRepository->findOneById($association->getId()))->isEmpty();
+    verify($this->subscriberSegmentsRepository->findOneById($association->getId()))->empty();
   }
 
   public function testItSetGlobalStatusUnsubscribedForUsersUnsyncedFromWooCommerceSegment(): void {
diff --git a/mailpoet/tests/integration/Statistics/Track/ClicksTest.php b/mailpoet/tests/integration/Statistics/Track/ClicksTest.php
index 6b97847c8c..25e3ab31d8 100644
--- a/mailpoet/tests/integration/Statistics/Track/ClicksTest.php
+++ b/mailpoet/tests/integration/Statistics/Track/ClicksTest.php
@@ -151,8 +151,8 @@ class ClicksTest extends \MailPoetTest {
     ], $this);
     $clicks->track($data);
 
-    expect($this->statisticsClicksRepository->findAll())->isEmpty();
-    expect($this->statisticsOpensRepository->findAll())->isEmpty();
+    verify($this->statisticsClicksRepository->findAll())->empty();
+    verify($this->statisticsOpensRepository->findAll())->empty();
   }
 
   public function testItTracksClickAndOpenEvent() {
diff --git a/mailpoet/tests/integration/Statistics/Track/OpensTest.php b/mailpoet/tests/integration/Statistics/Track/OpensTest.php
index df2d84f1a0..8f61ca0ced 100644
--- a/mailpoet/tests/integration/Statistics/Track/OpensTest.php
+++ b/mailpoet/tests/integration/Statistics/Track/OpensTest.php
@@ -97,7 +97,7 @@ class OpensTest extends \MailPoetTest {
       'returnResponse' => Expected::exactly(1),
     ], $this);
     $opens->track(false);
-    expect($this->statisticsOpensRepository->findAll())->isEmpty();
+    verify($this->statisticsOpensRepository->findAll())->empty();
   }
 
   public function testItDoesNotTrackOpenEventFromWpUserWhenPreviewIsEnabled() {
@@ -112,11 +112,11 @@ class OpensTest extends \MailPoetTest {
       'returnResponse' => null,
     ], $this);
     $opens->track($data);
-    expect($this->statisticsOpensRepository->findAll())->isEmpty();
+    verify($this->statisticsOpensRepository->findAll())->empty();
   }
 
   public function testItReturnsNothingWhenImageDisplayIsDisabled() {
-    expect($this->opens->track($this->trackData, $displayImage = false))->isEmpty();
+    verify($this->opens->track($this->trackData, $displayImage = false))->empty();
   }
 
   public function testItTracksOpenEvent() {
diff --git a/mailpoet/tests/integration/Subscribers/ImportExport/Import/ImportTest.php b/mailpoet/tests/integration/Subscribers/ImportExport/Import/ImportTest.php
index 3343e2e58e..086abd2ef3 100644
--- a/mailpoet/tests/integration/Subscribers/ImportExport/Import/ImportTest.php
+++ b/mailpoet/tests/integration/Subscribers/ImportExport/Import/ImportTest.php
@@ -252,7 +252,7 @@ class ImportTest extends \MailPoetTest {
     $result = $this->import->validateSubscribersData($data);
     $this->assertIsArray($result);
     expect($result['confirmed_ip'])->count(2);
-    expect($result['confirmed_ip'][0])->isEmpty();
+    verify($result['confirmed_ip'][0])->empty();
     verify($result['confirmed_ip'][1])->equals('192.68.69.32');
 
     // invalid IPv4 confirmed_ip is empty in the data object
@@ -263,7 +263,7 @@ class ImportTest extends \MailPoetTest {
     $result = $this->import->validateSubscribersData($data);
     $this->assertIsArray($result);
     expect($result['confirmed_ip'])->count(2);
-    expect($result['confirmed_ip'][0])->isEmpty();
+    verify($result['confirmed_ip'][0])->empty();
     verify($result['confirmed_ip'][1])->equals('192.68.69.32');
 
     // Empty confirmed_ip is empty in the data object
@@ -274,7 +274,7 @@ class ImportTest extends \MailPoetTest {
     $result = $this->import->validateSubscribersData($data);
     $this->assertIsArray($result);
     expect($result['confirmed_ip'])->count(2);
-    expect($result['confirmed_ip'][0])->isEmpty();
+    verify($result['confirmed_ip'][0])->empty();
     verify($result['confirmed_ip'][1])->equals('192.68.69.32');
 
     // normalize confirmed_at
diff --git a/mailpoet/tests/integration/Subscribers/SubscriberActionsTest.php b/mailpoet/tests/integration/Subscribers/SubscriberActionsTest.php
index 63b527f4df..b717f7f7b2 100644
--- a/mailpoet/tests/integration/Subscribers/SubscriberActionsTest.php
+++ b/mailpoet/tests/integration/Subscribers/SubscriberActionsTest.php
@@ -232,7 +232,7 @@ class SubscriberActionsTest extends \MailPoetTest {
     $this->assertInstanceOf(SubscriberCustomFieldEntity::class, $subscriberCustomField);
     verify($subscriberCustomField->getValue())->equals($data['cf_' . $customField->getId()]);
 
-    expect($subscriber->getUnconfirmedData())->isEmpty();
+    verify($subscriber->getUnconfirmedData())->empty();
 
     $data2 = $data;
     $data2['first_name'] = 'Aaa';
@@ -261,7 +261,7 @@ class SubscriberActionsTest extends \MailPoetTest {
     // during confirmation, manual admin editing
     $saveController = ContainerWrapper::getInstance()->get(SubscriberSaveController::class);
     $subscriber = $saveController->createOrUpdate($data2, $subscriber);
-    expect($subscriber->getUnconfirmedData())->isEmpty();
+    verify($subscriber->getUnconfirmedData())->empty();
 
     $this->settings->set('signup_confirmation.enabled', $originalSettingValue);
   }
diff --git a/mailpoet/tests/integration/Subscription/FormTest.php b/mailpoet/tests/integration/Subscription/FormTest.php
index 39e0e5c7d7..5ac1f4c790 100644
--- a/mailpoet/tests/integration/Subscription/FormTest.php
+++ b/mailpoet/tests/integration/Subscription/FormTest.php
@@ -120,7 +120,7 @@ class FormTest extends \MailPoetTest {
     ], $this);
     $formController = new Form(ContainerWrapper::getInstance()->get(API::class), $urlHelper);
     $result = $formController->onSubmit($requestData);
-    expect($this->subscribersRepository->findAll())->isEmpty();
+    verify($this->subscribersRepository->findAll())->empty();
     verify($result['mailpoet_error'])->equals($this->form->getId());
     verify($result['mailpoet_success'])->null();
   }
diff --git a/mailpoet/tests/integration/Tasks/SendingTest.php b/mailpoet/tests/integration/Tasks/SendingTest.php
index ae805abe2d..f11e52bb23 100644
--- a/mailpoet/tests/integration/Tasks/SendingTest.php
+++ b/mailpoet/tests/integration/Tasks/SendingTest.php
@@ -66,7 +66,7 @@ class SendingTest extends \MailPoetTest {
   public function testItDeletesInvalidTasksWhenCreatingManyFromTasks() {
     $this->queue->delete();
     $sendings = SendingTask::createManyFromTasks([$this->task]);
-    expect($sendings)->isEmpty();
+    verify($sendings)->empty();
     $task = ScheduledTask::findOne($this->task->id);
     $this->assertInstanceOf(ScheduledTask::class, $task);
     verify($task->status)->equals(ScheduledTask::STATUS_INVALID);
@@ -115,7 +115,7 @@ class SendingTest extends \MailPoetTest {
     $this->sending->delete();
     verify(ScheduledTask::findOne($this->task->id))->equals(false);
     verify(SendingQueue::findOne($this->queue->id))->equals(false);
-    expect(ScheduledTaskSubscriber::where('task_id', $this->task->id)->findMany())->isEmpty();
+    verify(ScheduledTaskSubscriber::where('task_id', $this->task->id)->findMany())->empty();
   }
 
   public function testItGetsSubscribers() {
@@ -171,7 +171,7 @@ class SendingTest extends \MailPoetTest {
     // if task exists but sending queue is missing, results should not contain empty (false) values
     $this->queue->delete();
     $tasks = $this->scheduledTaskRepository->findRunningSendingTasks();
-    expect($tasks)->isEmpty();
+    verify($tasks)->empty();
   }
 
   public function testItGetsBatchOfScheduledQueues() {
@@ -200,7 +200,7 @@ class SendingTest extends \MailPoetTest {
     // if task exists but sending queue is missing, results should not contain empty (false) values
     $this->queue->delete();
     $tasks = $this->scheduledTaskRepository->findRunningSendingTasks();
-    expect($tasks)->isEmpty();
+    verify($tasks)->empty();
   }
 
   public function testItGetsBatchOfRunningQueues() {
diff --git a/mailpoet/tests/integration/Twig/FunctionsTest.php b/mailpoet/tests/integration/Twig/FunctionsTest.php
index 11a912c27a..2f08646f91 100644
--- a/mailpoet/tests/integration/Twig/FunctionsTest.php
+++ b/mailpoet/tests/integration/Twig/FunctionsTest.php
@@ -19,6 +19,6 @@ class FunctionsTest extends \MailPoetTest {
     $resultRtl = $twig->render('template');
     verify($resultRtl)->equals('rtl');
     $resultNoRtl = $twig->render('template');
-    expect($resultNoRtl)->isEmpty();
+    verify($resultNoRtl)->empty();
   }
 }
diff --git a/mailpoet/tests/integration/Util/Notices/AfterMigrationNoticeTest.php b/mailpoet/tests/integration/Util/Notices/AfterMigrationNoticeTest.php
index 820a510670..979bb61923 100644
--- a/mailpoet/tests/integration/Util/Notices/AfterMigrationNoticeTest.php
+++ b/mailpoet/tests/integration/Util/Notices/AfterMigrationNoticeTest.php
@@ -6,14 +6,14 @@ class AfterMigrationNoticeTest extends \MailPoetTest {
   public function testItDoesntDisplayIfShouldntDisplay() {
     $notice = new AfterMigrationNotice();
     $result = $notice->init(false);
-    expect($result)->isEmpty();
+    verify($result)->empty();
   }
 
   public function testItDoesntDisplayIfDisabled() {
     $notice = new AfterMigrationNotice();
     $notice->disable();
     $result = $notice->init(true);
-    expect($result)->isEmpty();
+    verify($result)->empty();
   }
 
   public function testItDisplayIfEnabled() {
diff --git a/mailpoet/tests/unit/EmailEditor/Engine/Renderer/PreprocessorTest.php b/mailpoet/tests/unit/EmailEditor/Engine/Renderer/PreprocessorTest.php
index 2a27002769..8a3abc1143 100644
--- a/mailpoet/tests/unit/EmailEditor/Engine/Renderer/PreprocessorTest.php
+++ b/mailpoet/tests/unit/EmailEditor/Engine/Renderer/PreprocessorTest.php
@@ -53,7 +53,7 @@ class PreprocessorTest extends \MailPoetUnitTest {
     verify($result[0]['innerBlocks'][0]['innerBlocks'][0]['blockName'])->equals('core/paragraph');
     // Second columns remains empty
     verify($result[1]['innerBlocks'][0]['blockName'])->equals('core/column');
-    expect($result[1]['innerBlocks'][0]['innerBlocks'])->isEmpty();
+    verify($result[1]['innerBlocks'][0]['innerBlocks'])->empty();
     // Third columns contain columns with two paragraph blocks
     verify($result[2]['innerBlocks'][0]['blockName'])->equals('core/column');
     expect($result[2]['innerBlocks'][0]['innerBlocks'])->count(2);
diff --git a/mailpoet/tests/unit/Entities/FormEntityTest.php b/mailpoet/tests/unit/Entities/FormEntityTest.php
index 0b2b334c8f..f77b2977f4 100644
--- a/mailpoet/tests/unit/Entities/FormEntityTest.php
+++ b/mailpoet/tests/unit/Entities/FormEntityTest.php
@@ -73,7 +73,7 @@ class FormEntityTest extends \MailPoetUnitTest {
     $formEntity = new FormEntity('Test' );
     $formEntity->setBody($this->body);
     $segmentIds = $formEntity->getSegmentBlocksSegmentIds();
-    expect($segmentIds)->isEmpty();
+    verify($segmentIds)->empty();
 
     // Add segment selection block to second columns
     $body = $this->body;
diff --git a/mailpoet/tests/unit/Features/FeaturesControllerTest.php b/mailpoet/tests/unit/Features/FeaturesControllerTest.php
index cd6fcddc21..3e871a3dbf 100644
--- a/mailpoet/tests/unit/Features/FeaturesControllerTest.php
+++ b/mailpoet/tests/unit/Features/FeaturesControllerTest.php
@@ -70,6 +70,6 @@ class FeaturesControllerTest extends \MailPoetUnitTest {
     } catch (\RuntimeException $e) {
       verify($e->getMessage())->equals("Unknown feature 'feature-unknown'");
     }
-    expect($controller->getAllFlags())->isEmpty();
+    verify($controller->getAllFlags())->empty();
   }
 }