diff --git a/tests/Console/ContaoApplicationTest.php b/tests/Console/ContaoApplicationTest.php
index 3ac847f..1d1a7a4 100644
--- a/tests/Console/ContaoApplicationTest.php
+++ b/tests/Console/ContaoApplicationTest.php
@@ -26,6 +26,8 @@ protected function setUp(): void
         parent::setUp();
 
         $this->backupServerEnvGetPost();
+
+        unset($_SERVER['APP_ENV'], $_ENV['APP_ENV']);
     }
 
     protected function tearDown(): void
diff --git a/tests/HttpKernel/ContaoKernelTest.php b/tests/HttpKernel/ContaoKernelTest.php
index 5d77d96..73e4c39 100644
--- a/tests/HttpKernel/ContaoKernelTest.php
+++ b/tests/HttpKernel/ContaoKernelTest.php
@@ -45,6 +45,8 @@ protected function setUp(): void
 
         $this->backupServerEnvGetPost();
 
+        $_ENV['APP_ENV'] = $_SERVER['APP_ENV'] = 'prod';
+
         $this->shellVerbosityBackup = getenv('SHELL_VERBOSITY');
     }
 
@@ -369,7 +371,7 @@ public function testReturnsTheContaoKernelInDevMode(): void
      */
     public function testReturnsTheContaoCacheInProdMode(): void
     {
-        unset($_SERVER['APP_ENV']);
+        unset($_SERVER['APP_ENV'], $_ENV['APP_ENV'], $_ENV['DISABLE_HTTP_CACHE'], $_SERVER['DISABLE_HTTP_CACHE']);
 
         $tempDir = realpath($this->getTempDir());
         $kernel = ContaoKernel::fromRequest($tempDir, Request::create('/'));