fixup! chore(tests): Adapt tests to IUser strict typing

Author: come-nc

tests/lib/TaskProcessing/TaskProcessingTest.php

@@ -912,7 +912,7 @@ public function testProviderShouldBeRegisteredAndTaskWithFilesFailValidation():
 			new ServiceRegistration('test', AsyncProvider::class)
 		]);
 		$user = $this->createMock(IUser::class);
-		$user->expects($this->any())->method('getUID')->willReturn(null);
+		$user->expects($this->any())->method('getUID')->willReturn('uid');
 		$mount = $this->createMock(ICachedMountInfo::class);
 		$mount->expects($this->any())->method('getUser')->willReturn($user);
 		$this->userMountCache->expects($this->any())->method('getMountsForFileId')->willReturn([$mount]);