diff --git a/tests/lib/Files/Cache/ScannerTest.php b/tests/lib/Files/Cache/ScannerTest.php
index 90c059238e3bb..0ec56213e3738 100644
--- a/tests/lib/Files/Cache/ScannerTest.php
+++ b/tests/lib/Files/Cache/ScannerTest.php
@@ -160,14 +160,14 @@ public function testBackgroundScan(): void {
 
 		$this->scanner->scan('', IScanner::SCAN_SHALLOW);
 		$this->assertFalse($this->cache->inCache('folder/bar.txt'));
-		$this->assertFalse($this->cache->inCache('folder/2bar.txt'));
+		$this->assertFalse($this->cache->inCache('folder2/bar.txt'));
 		$cachedData = $this->cache->get('');
 		$this->assertEquals(-1, $cachedData['size']);
 
 		$this->scanner->backgroundScan();
 
 		$this->assertTrue($this->cache->inCache('folder/bar.txt'));
-		$this->assertTrue($this->cache->inCache('folder/bar.txt'));
+		$this->assertTrue($this->cache->inCache('folder2/bar.txt'));
 
 		$cachedData = $this->cache->get('');
 		$this->assertnotEquals(-1, $cachedData['size']);
@@ -182,16 +182,15 @@ public function testBackgroundScanOnlyRecurseIncomplete(): void {
 
 		$this->scanner->scan('', IScanner::SCAN_SHALLOW);
 		$this->assertFalse($this->cache->inCache('folder/bar.txt'));
-		$this->assertFalse($this->cache->inCache('folder/2bar.txt'));
 		$this->assertFalse($this->cache->inCache('folder2/bar.txt'));
-		$this->cache->put('folder2', ['size' => 1]); // mark as complete
+		// Mark folder2 complete so the incomplete-only scan skips its contents.
+		$this->cache->put('folder2', ['size' => 1]);
 
 		$cachedData = $this->cache->get('');
 		$this->assertEquals(-1, $cachedData['size']);
 
 		$this->scanner->scan('', IScanner::SCAN_RECURSIVE_INCOMPLETE, IScanner::REUSE_ETAG | IScanner::REUSE_SIZE);
 
-		$this->assertTrue($this->cache->inCache('folder/bar.txt'));
 		$this->assertTrue($this->cache->inCache('folder/bar.txt'));
 		$this->assertFalse($this->cache->inCache('folder2/bar.txt'));
 
@@ -212,7 +211,7 @@ public function testBackgroundScanNestedIncompleteFolders(): void {
 		$this->cache->put('folder', ['size' => -1]);
 		$this->cache->put('folder/subfolder1', ['size' => -1]);
 
-		// do a scan to get the folders into the cache.
+		// Cache the newly created directory tree before adding files to it.
 		$this->scanner->backgroundScan();
 
 		$this->assertTrue($this->cache->inCache('folder/subfolder1/subfolder3'));
@@ -221,7 +220,7 @@ public function testBackgroundScanNestedIncompleteFolders(): void {
 		$this->storage->file_put_contents('folder/subfolder1/subfolder3/bar3.txt', 'foobar');
 		$this->storage->file_put_contents('folder/subfolder2/bar2.txt', 'foobar');
 
-		//mark folders as incomplete.
+		// Mark the new files' parent folders incomplete to simulate notifications.
 		$this->cache->put('folder/subfolder1', ['size' => -1]);
 		$this->cache->put('folder/subfolder2', ['size' => -1]);
 		$this->cache->put('folder/subfolder1/subfolder3', ['size' => -1]);
@@ -232,7 +231,6 @@ public function testBackgroundScanNestedIncompleteFolders(): void {
 		$this->assertTrue($this->cache->inCache('folder/subfolder2/bar2.txt'));
 		$this->assertTrue($this->cache->inCache('folder/subfolder1/subfolder3/bar3.txt'));
 
-		//check if folder sizes are correct.
 		$this->assertEquals(18, $this->cache->get('folder')['size']);
 		$this->assertEquals(12, $this->cache->get('folder/subfolder1')['size']);
 		$this->assertEquals(6, $this->cache->get('folder/subfolder1/subfolder3')['size']);
@@ -314,7 +312,7 @@ public function testETagRecreation(): void {
 
 		$this->scanner->scan('folder/bar.txt');
 
-		// manipulate etag to simulate an empty etag
+		// Simulate a cached file with an empty ETag.
 		$this->scanner->scan('', IScanner::SCAN_SHALLOW, IScanner::REUSE_ETAG);
 		/** @var CacheEntry $data0 */
 		$data0 = $this->cache->get('folder/bar.txt');
@@ -326,10 +324,10 @@ public function testETagRecreation(): void {
 		$data0['etag'] = '';
 		$this->cache->put('folder/bar.txt', $data0->getData());
 
-		// rescan
+		// Rescanning must replace the empty cached ETag.
 		$this->scanner->scan('folder/bar.txt', IScanner::SCAN_SHALLOW, IScanner::REUSE_ETAG);
 
-		// verify cache content
+		// The recreated ETag must be non-empty.
 		$newData0 = $this->cache->get('folder/bar.txt');
 		$this->assertIsString($newData0['etag']);
 		$this->assertNotEmpty($newData0['etag']);
@@ -415,14 +413,14 @@ public function testNoETagUnscannedFolder(): void {
 		$this->scanner->scan('');
 
 		$oldFolderEntry = $this->cache->get('folder');
-		// create a new file in a folder by keeping the mtime unchanged, but mark the folder as unscanned
+		// Add a file without changing the folder mtime, then mark the folder unscanned.
 		$this->storage->file_put_contents('folder/new.txt', 'foo');
 		$this->storage->touch('folder', $oldFolderEntry->getMTime());
 		$this->cache->update($oldFolderEntry->getId(), ['size' => -1]);
 
 		$this->scanner->scan('');
 
-		$this->cache->inCache('folder/new.txt');
+		$this->assertTrue($this->cache->inCache('folder/new.txt'));
 
 		$newFolderEntry = $this->cache->get('folder');
 		$this->assertNotEquals($newFolderEntry->getEtag(), $oldFolderEntry->getEtag());
@@ -436,17 +434,18 @@ public function testNoETagUnscannedSubFolder(): void {
 
 		$oldFolderEntry1 = $this->cache->get('folder');
 		$oldFolderEntry2 = $this->cache->get('folder/sub');
-		// create a new file in a folder by keeping the mtime unchanged, but mark the folder as unscanned
+		// Add a file without changing its parent folder's mtime, then mark that folder unscanned.
 		$this->storage->file_put_contents('folder/sub/new.txt', 'foo');
-		$this->storage->touch('folder/sub', $oldFolderEntry1->getMTime());
+		$this->storage->touch('folder/sub', $oldFolderEntry2->getMTime());
 
-		// we only mark the direct parent as unscanned, which is the current "notify" behavior
+		// Notifications mark the new file's direct parent as unscanned, not its ancestors.
 		$this->cache->update($oldFolderEntry2->getId(), ['size' => -1]);
 
 		$this->scanner->scan('');
 
-		$this->cache->inCache('folder/new.txt');
+		$this->assertTrue($this->cache->inCache('folder/sub/new.txt'));
 
+		// The changed subfolder ETag must also be reflected in its ancestor.
 		$newFolderEntry1 = $this->cache->get('folder');
 		$this->assertNotEquals($newFolderEntry1->getEtag(), $oldFolderEntry1->getEtag());
 		$newFolderEntry2 = $this->cache->get('folder/sub');