diff --git a/phpunit.xml b/phpunit.xml
index a199dcf3..e9a25f46 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -38,5 +38,6 @@
         <env name="SESSION_DRIVER" value="array"/>
         <env name="TELESCOPE_ENABLED" value="false"/>
         <env name="AUDITING_ENABLED" value="true"/>
+        <env name="NEWSLETTER_URL" value="null"/>
     </php>
 </phpunit>
diff --git a/tests/TestCase.php b/tests/TestCase.php
index 54f86be5..cc158eca 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -11,6 +11,7 @@ use Carbon\CarbonImmutable;
 use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Foundation\Testing\TestCase as BaseTestCase;
 use Illuminate\Support\Carbon;
+use Illuminate\Support\Facades\Http;
 use Illuminate\Support\Facades\Mail;
 use Illuminate\Support\Facades\Storage;
 use Mockery\MockInterface;
@@ -25,6 +26,7 @@ abstract class TestCase extends BaseTestCase
         parent::setUp();
         Mail::fake();
         LogFake::bind();
+        Http::preventStrayRequests();
         $this->actAsOrganizationWithoutSubscriptionAndWithoutTrial();
         // Note: The following line can be used to test timezone edge cases.
         // $this->travelTo(Carbon::now()->timezone('Europe/Vienna')->setHour(0)->setMinute(59)->setSecond(0));