diff --git a/server/scanner/LibraryItemScanData.js b/server/scanner/LibraryItemScanData.js
index f583b8278..032a636cd 100644
--- a/server/scanner/LibraryItemScanData.js
+++ b/server/scanner/LibraryItemScanData.js
@@ -243,7 +243,7 @@ class LibraryItemScanData {
       } else {
         libraryFilesAdded = libraryFilesAdded.filter((lf) => lf !== matchingLibraryFile)
         let existingLibraryFileBefore = structuredClone(existingLibraryFile)
-        if (this.compareUpdateLibraryFile(existingLibraryItem.path, existingLibraryFile, matchingLibraryFile, libraryScan)) {
+        if (LibraryItemScanData.compareUpdateLibraryFile(existingLibraryItem.path, existingLibraryFile, matchingLibraryFile, libraryScan)) {
           this.libraryFilesModified.push({ old: existingLibraryFileBefore, new: existingLibraryFile })
           this.hasChanges = true
         }
@@ -289,10 +289,10 @@ class LibraryItemScanData {
    * @param {string} libraryItemPath
    * @param {LibraryItem.LibraryFileObject} existingLibraryFile
    * @param {import('../objects/files/LibraryFile')} scannedLibraryFile
-   * @param {import('./LibraryScan')} libraryScan
+   * @param {import('./LibraryScan') | import('./ScanLogger')} libraryScan
    * @returns {boolean} false if no changes
    */
-  compareUpdateLibraryFile(libraryItemPath, existingLibraryFile, scannedLibraryFile, libraryScan) {
+  static compareUpdateLibraryFile(libraryItemPath, existingLibraryFile, scannedLibraryFile, libraryScan) {
     let hasChanges = false
 
     if (existingLibraryFile.ino !== scannedLibraryFile.ino && existingLibraryFile.deviceId !== scannedLibraryFile.deviceId) {
diff --git a/test/server/MockDatabase.js b/test/server/MockDatabase.js
index 880eded69..142eb4af2 100644
--- a/test/server/MockDatabase.js
+++ b/test/server/MockDatabase.js
@@ -2,6 +2,8 @@ const Database = require('../../server/Database')
 const { Sequelize } = require('sequelize')
 const LibraryFile = require('../../server/objects/files/LibraryFile')
 const fileUtils = require('../../server/utils/fileUtils')
+const FileMetadata = require('../../server/objects/metadata/FileMetadata')
+const Path = require('path')
 const sinon = require('sinon')
 
 async function loadTestDatabase(mockFileInfo) {
@@ -120,3 +122,22 @@ function stubFileUtils() {
   })
 }
 exports.stubFileUtils = stubFileUtils
+
+/** @returns {{ libraryFolderId: any; libraryId: any; mediaType: any; ino: any; deviceId: any; mtimeMs: any; ctimeMs: any; birthtimeMs: any; path: any; relPath: any; isFile: any; mediaMetadata: any; libraryFiles: any; }} */
+function buildFileProperties(path = '/tmp/foo.epub', ino = '12345', deviceId = '9876') {
+  const metadata = new FileMetadata()
+  metadata.filename = Path.basename(path)
+  metadata.path = path
+  metadata.relPath = path
+  metadata.ext = Path.extname(path)
+
+  return {
+    ino: ino,
+    deviceId: deviceId,
+    metadata: metadata,
+    isSupplementary: false,
+    addedAt: Date.now(),
+    updatedAt: Date.now()
+  }
+}
+exports.buildFileProperties = buildFileProperties
diff --git a/test/server/objects/LibraryItemScanData.test.js b/test/server/objects/LibraryItemScanData.test.js
index 6322ef7db..03ef963aa 100644
--- a/test/server/objects/LibraryItemScanData.test.js
+++ b/test/server/objects/LibraryItemScanData.test.js
@@ -1,5 +1,68 @@
+const chai = require('chai')
+const expect = chai.expect
+const sinon = require('sinon')
+const rewire = require('rewire')
+const Path = require('path')
+
+const { stubFileUtils, getMockFileInfo, loadTestDatabase, buildFileProperties } = require('../MockDatabase')
+
+const LibraryItemScanData = require('../../../server/scanner/LibraryItemScanData')
+const LibraryFile = require('../../../server/objects/files/LibraryFile')
+const LibraryScan = require('../../../server/scanner/LibraryScan')
+
 // TODO - need to check
-// compareUpdateLibraryFile
+// compareUpdateLibraryFile - returns false if no changes; true if changes
+describe('compareUpdateLibraryFileWithDeviceId', () => {
+  it('fileChangeDetectedWhenInodeAndDeviceIdPairDiffers', () => {
+    const existing_lf = buildLibraryFileObject('/tmp/file.pdf', '4432', '300')
+    const scanned_lf = new LibraryFile({
+      ino: '1',
+      deviceId: '100'
+    })
+
+    expect(existing_lf.ino).to.not.equal(scanned_lf.ino)
+    expect(existing_lf.deviceId).to.not.equal(scanned_lf.deviceId)
+    const changeDetected = LibraryItemScanData.compareUpdateLibraryFile('/file/path.pdf', existing_lf, scanned_lf, new LibraryScan())
+    expect(changeDetected).to.be.true
+  })
+
+  it('fileChangeNotDetectedWhenInodeSameButDeviceIdDiffers', () => {
+    // Same inode on different deviceId does NOT mean these are the same file
+    const existing_lf = buildLibraryFileObject('/tmp/file.pdf', '4432', '300')
+    const scanned_lf = new LibraryFile(buildLibraryFileObject('/tmp/file.pdf', '4432', '100'))
+
+    expect(existing_lf.ino).to.equal(scanned_lf.ino)
+    expect(existing_lf.deviceId).to.not.equal(scanned_lf.deviceId)
+    const changeDetected = LibraryItemScanData.compareUpdateLibraryFile('/file/path.pdf', existing_lf, scanned_lf, new LibraryScan())
+    expect(changeDetected).to.be.false
+  })
+})
+
+/**
+ * @returns {import('../../../server/models/LibraryItem').LibraryFileObject}
+ * @param {string} [path]
+ * @param {string} [ino]
+ * @param {string} [deviceId]
+ */
+function buildLibraryFileObject(path, ino, deviceId) {
+  return {
+    ino: ino,
+    deviceId: deviceId,
+    isSupplementary: false,
+    addedAt: 0,
+    updatedAt: 0,
+    metadata: {
+      filename: Path.basename(path),
+      ext: Path.extname(path),
+      path: path,
+      relPath: path,
+      size: 0,
+      mtimeMs: 0,
+      ctimeMs: 0,
+      birthtimeMs: 0
+    }
+  }
+}
 // checkEbookFileRemoved
 // checkAudioFileRemoved
 // libraryItemObject()
diff --git a/test/server/objects/SimilarLibraryFileObjects.test.js b/test/server/objects/SimilarLibraryFileObjects.test.js
index 0b9308fb0..d71df8fa0 100644
--- a/test/server/objects/SimilarLibraryFileObjects.test.js
+++ b/test/server/objects/SimilarLibraryFileObjects.test.js
@@ -4,14 +4,13 @@ const sinon = require('sinon')
 
 const Path = require('path')
 const Database = require('../../../server/Database')
-const { loadTestDatabase, stubFileUtils, getMockFileInfo } = require('../MockDatabase')
+const { loadTestDatabase, stubFileUtils, getMockFileInfo, buildFileProperties } = require('../MockDatabase')
 
 // TODO: all of these classes duplicate each other.
 const LibraryFile = require('../../../server/objects/files/LibraryFile')
 const EBookFile = require('../../../server/objects/files/EBookFile')
 const AudioFile = require('../../../server/objects/files/AudioFile')
 const LibraryItemScanData = require('../../../server/scanner/LibraryItemScanData')
-const FileMetadata = require('../../../server/objects/metadata/FileMetadata')
 
 const fileProperties = buildFileProperties()
 const lf = new LibraryFile(fileProperties)
@@ -77,25 +76,6 @@ describe('ObjectSetsDeviceIdWhenSerialized', () => {
   })
 })
 
-/** @returns {{ libraryFolderId: any; libraryId: any; mediaType: any; ino: any; deviceId: any; mtimeMs: any; ctimeMs: any; birthtimeMs: any; path: any; relPath: any; isFile: any; mediaMetadata: any; libraryFiles: any; }} */
-function buildFileProperties() {
-  const path = '/tmp/foo.epub'
-  const metadata = new FileMetadata()
-  metadata.filename = Path.basename(path)
-  metadata.path = path
-  metadata.relPath = path
-  metadata.ext = Path.extname(path)
-
-  return {
-    ino: '12345',
-    deviceId: '9876',
-    metadata: metadata,
-    isSupplementary: false,
-    addedAt: Date.now(),
-    updatedAt: Date.now()
-  }
-}
-
 function buildLibraryItemProperties(fileProperties) {
   return {
     id: '7792E90F-D526-4636-8A38-EA8342E71FEE',