Fix for the issues raised in the code review

browser/main/lib/dataApi/attachmentManagement.js

@@ -232,7 +232,7 @@ function deleteAttachmentFolder (storageKey, noteKey) {
  * @param noteKey NoteKey of the current note. Is used to determine the belonging attachment folder.
  */
 function deleteAttachmentsNotPresentInNote (markdownContent, storageKey, noteKey) {
-  if (storageKey && noteKey && markdownContent !== null && typeof markdownContent !== 'undefined') {
+  if (storageKey != null && noteKey != null && markdownContent != null) {
     const targetStorage = findStorage.findStorage(storageKey)
     const attachmentFolder = path.join(targetStorage.path, DESTINATION_FOLDER, noteKey)
     const attachmentsInNote = getAttachmentsInContent(markdownContent)

tests/dataApi/attachmentManagement.test.js

@@ -383,3 +383,35 @@ it('should test that moveAttachments returns a correct modified content version'
   const actualContent = systemUnderTest.moveAttachments(oldPath, newPath, oldNoteKey, newNoteKey, testInput)
   expect(actualContent).toBe(expectedOutput)
 })
+
+it('should test that deleteAttachmentsNotPresentInNote does nothing if noteKey, storageKey or noteContent was null', function () {
+  const noteKey = null
+  const storageKey = null
+  const markdownContent = ''
+
+  findStorage.findStorage = jest.fn()
+  fs.existsSync = jest.fn()
+  fs.readdir = jest.fn()
+  fs.unlink = jest.fn()
+
+  systemUnderTest.deleteAttachmentsNotPresentInNote(markdownContent, storageKey, noteKey)
+  expect(fs.existsSync).not.toHaveBeenCalled()
+  expect(fs.readdir).not.toHaveBeenCalled()
+  expect(fs.unlink).not.toHaveBeenCalled()
+})
+
+it('should test that deleteAttachmentsNotPresentInNote does nothing if noteKey, storageKey or noteContent was undefined', function () {
+  const noteKey = undefined
+  const storageKey = undefined
+  const markdownContent = ''
+
+  findStorage.findStorage = jest.fn()
+  fs.existsSync = jest.fn()
+  fs.readdir = jest.fn()
+  fs.unlink = jest.fn()
+
+  systemUnderTest.deleteAttachmentsNotPresentInNote(markdownContent, storageKey, noteKey)
+  expect(fs.existsSync).not.toHaveBeenCalled()
+  expect(fs.readdir).not.toHaveBeenCalled()
+  expect(fs.unlink).not.toHaveBeenCalled()
+})