diff --git a/apps/files_sharing/tests/ShareMountEventsTest.php b/apps/files_sharing/tests/ShareMountEventsTest.php
new file mode 100644
index 0000000000000..28cd0bdcdcd67
--- /dev/null
+++ b/apps/files_sharing/tests/ShareMountEventsTest.php
@@ -0,0 +1,134 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Files_Sharing\Tests;
+
+use OCA\Files_Sharing\Listener\SharesUpdatedListener;
+use OCP\Constants;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\Files\Config\Event\UserMountAddedEvent;
+use OCP\Files\Config\Event\UserMountRemovedEvent;
+use OCP\Files\Folder;
+use OCP\Server;
+use OCP\Share\IShare;
+use PHPUnit\Framework\Attributes\DataProvider;
+
+/**
+ * Apps like recognize keep per-user data in sync with file access by listening to
+ * UserMountAddedEvent and UserMountRemovedEvent. These events have to be dispatched
+ * for the recipients of a share when it is created or deleted, at the latest when a
+ * recipient sets up their file system afterwards, regardless of whether the share
+ * mounts of the recipient are updated immediately or deferred until then.
+ */
+#[\PHPUnit\Framework\Attributes\Group(name: 'DB')]
+class ShareMountEventsTest extends TestCase {
+	private const FOLDER = 'shared-folder';
+
+	private IEventDispatcher $eventDispatcher;
+	/** @var list<Event> */
+	private array $events = [];
+	/** @var \Closure(Event): void */
+	private \Closure $listener;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->eventDispatcher = Server::get(IEventDispatcher::class);
+		$this->listener = function (Event $event): void {
+			$this->events[] = $event;
+		};
+		$this->eventDispatcher->addListener(UserMountAddedEvent::class, $this->listener);
+		$this->eventDispatcher->addListener(UserMountRemovedEvent::class, $this->listener);
+
+		$this->rootFolder->getUserFolder(self::TEST_FILES_SHARING_API_USER1)->newFolder(self::FOLDER);
+
+		// The recipient has used their file system before
+		$this->assertFalse($this->getUserFolder(self::TEST_FILES_SHARING_API_USER2)->nodeExists(self::FOLDER));
+		$this->loginHelper(self::TEST_FILES_SHARING_API_USER1);
+		$this->events = [];
+	}
+
+	protected function tearDown(): void {
+		$this->eventDispatcher->removeListener(UserMountAddedEvent::class, $this->listener);
+		$this->eventDispatcher->removeListener(UserMountRemovedEvent::class, $this->listener);
+		Server::get(SharesUpdatedListener::class)->setCutOffMarkTime(-1);
+
+		parent::tearDown();
+	}
+
+	/**
+	 * @return array<string, array{int, string, float}>
+	 */
+	public static function shareProvider(): array {
+		// A cutoff time of -1 updates the share mounts of recipients immediately,
+		// 0 marks recipients so their share mounts are updated on their next setup
+		return [
+			'user share, immediate update' => [IShare::TYPE_USER, self::TEST_FILES_SHARING_API_USER2, -1],
+			'user share, deferred update' => [IShare::TYPE_USER, self::TEST_FILES_SHARING_API_USER2, 0],
+			'group share, immediate update' => [IShare::TYPE_GROUP, self::TEST_FILES_SHARING_API_GROUP1, -1],
+			'group share, deferred update' => [IShare::TYPE_GROUP, self::TEST_FILES_SHARING_API_GROUP1, 0],
+		];
+	}
+
+	#[DataProvider(methodName: 'shareProvider')]
+	public function testMountAddedEventForCreatedShare(int $shareType, string $recipient, float $cutOffTime): void {
+		Server::get(SharesUpdatedListener::class)->setCutOffMarkTime($cutOffTime);
+
+		$this->share($shareType, self::FOLDER, self::TEST_FILES_SHARING_API_USER1, $recipient, Constants::PERMISSION_ALL);
+		$this->getUserFolder(self::TEST_FILES_SHARING_API_USER2)->get(self::FOLDER);
+
+		$this->assertEquals(
+			['/' . self::TEST_FILES_SHARING_API_USER2 . '/files/' . self::FOLDER . '/'],
+			$this->getMountPointsOfEvents(UserMountAddedEvent::class, self::TEST_FILES_SHARING_API_USER2),
+			'A UserMountAddedEvent should be dispatched for the share mount of the recipient',
+		);
+	}
+
+	#[DataProvider(methodName: 'shareProvider')]
+	public function testMountRemovedEventForDeletedShare(int $shareType, string $recipient, float $cutOffTime): void {
+		$share = $this->share($shareType, self::FOLDER, self::TEST_FILES_SHARING_API_USER1, $recipient, Constants::PERMISSION_ALL);
+		$this->getUserFolder(self::TEST_FILES_SHARING_API_USER2)->get(self::FOLDER);
+		$this->loginHelper(self::TEST_FILES_SHARING_API_USER1);
+		$this->events = [];
+
+		Server::get(SharesUpdatedListener::class)->setCutOffMarkTime($cutOffTime);
+		$this->shareManager->deleteShare($share);
+		$this->assertFalse(
+			$this->getUserFolder(self::TEST_FILES_SHARING_API_USER2)->nodeExists(self::FOLDER),
+			'The share should no longer be mounted for the recipient',
+		);
+
+		$this->assertEquals(
+			['/' . self::TEST_FILES_SHARING_API_USER2 . '/files/' . self::FOLDER . '/'],
+			$this->getMountPointsOfEvents(UserMountRemovedEvent::class, self::TEST_FILES_SHARING_API_USER2),
+			'A UserMountRemovedEvent should be dispatched for the share mount of the recipient',
+		);
+	}
+
+	/**
+	 * Log in as the user and get their user folder, as a new request by them would
+	 */
+	private function getUserFolder(string $userId): Folder {
+		$this->loginHelper($userId);
+		return $this->rootFolder->getUserFolder($userId);
+	}
+
+	/**
+	 * @param class-string<UserMountAddedEvent|UserMountRemovedEvent> $eventClass
+	 * @return list<string>
+	 */
+	private function getMountPointsOfEvents(string $eventClass, string $userId): array {
+		$mountPoints = [];
+		foreach ($this->events as $event) {
+			if ($event instanceof $eventClass && $event->mountPoint->getUser()->getUID() === $userId) {
+				$mountPoints[] = $event->mountPoint->getMountPoint();
+			}
+		}
+		return $mountPoints;
+	}
+}