diff --git a/tests/ACL/ACLScannerTest.php b/tests/ACL/ACLScannerTest.php
index c6f72b523..622f0632d 100644
--- a/tests/ACL/ACLScannerTest.php
+++ b/tests/ACL/ACLScannerTest.php
@@ -40,6 +40,7 @@ public function testScanAclStorage(): void {
 		$cache->calculateFolderSize('foo/bar');
 		$cache->calculateFolderSize('foo');
 
+		/** @psalm-suppress PossiblyFalseReference */
 		$this->assertEquals(-1, $cache->get('foo/bar')->getSize());
 
 		$acls = $this->getAclManager([
@@ -57,8 +58,10 @@ public function testScanAclStorage(): void {
 		$aclCache = $aclStorage->getCache();
 		$scanner->scan('');
 
+		/** @psalm-suppress PossiblyFalseReference */
 		$this->assertEquals(0, $cache->get('foo/bar')->getSize());
 
+		/** @psalm-suppress PossiblyFalseReference */
 		$this->assertEquals(31, $cache->get('foo/bar')->getPermissions());
 		$this->assertEquals(false, $aclCache->get('foo/bar'));
 	}
diff --git a/tests/ACL/ACLStorageWrapperTest.php b/tests/ACL/ACLStorageWrapperTest.php
index 6eabafd46..e448d7b17 100644
--- a/tests/ACL/ACLStorageWrapperTest.php
+++ b/tests/ACL/ACLStorageWrapperTest.php
@@ -59,6 +59,7 @@ public function testOpenDir(): void {
 
 		$dh = $this->storage->opendir('foo');
 		$result = [];
+		/** @psalm-suppress PossiblyFalseArgument */
 		while ($file = readdir($dh)) {
 			$result[] = $file;
 		}
diff --git a/tests/ACL/RuleManagerTest.php b/tests/ACL/RuleManagerTest.php
index 6db0cc766..c4272b861 100644
--- a/tests/ACL/RuleManagerTest.php
+++ b/tests/ACL/RuleManagerTest.php
@@ -40,7 +40,9 @@ protected function setUp(): void {
 		$this->userMappingManager = $this->createMock(IUserMappingManager::class);
 		$this->userMappingManager->expects($this->any())
 			->method('mappingFromId')
-			->willReturnCallback(fn (string $type, string $id): UserMapping => new UserMapping($type, $id));
+			->willReturnCallback(fn (string $type, string $id): UserMapping =>
+	   /** @var 'user'|'group'|'dummy' $type */
+	   new UserMapping($type, $id));
 
 		$this->eventDispatcher = $this->createMock(IEventDispatcher::class);
 		$this->ruleManager = new RuleManager(Server::get(IDBConnection::class), $this->userMappingManager, $this->eventDispatcher);