fix: task 10 + review fix #1 — thread safety and sleep bug

Fix #1: Don't sleep after the final exhausted retry attempt in
_graph_request(). The sleep on the last iteration was pure overhead —
the loop exits immediately after, so the caller just waited an extra
backoff period for no reason. Guard with attempt < _MAX_RETRIES - 1.

Task 10: Add threading.Lock (_edits_lock) for all compound operations
on active_edits, which is accessed from both the UI thread and
background edit threads:
- __init__: declare self._edits_lock = threading.Lock()
- open_file: snapshot already_editing and at_limit under the lock,
  then release before showing blocking UI dialogs
- process_file: wrap initial dict assignment, waiting=True, the
  in-check+waiting=False, and in-check+del under the lock
- on_done_editing_clicked: lock the items() snapshot used to build
  waiting_files, preventing iteration over a dict being mutated

Add 8 new unit tests (1 for Fix #1 sleep count, 7 for Task 10 lock).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

sharepoint_browser.py

@@ -67,13 +67,36 @@ def load_settings():
     with open(SETTINGS_FILE, 'r', encoding='utf-8') as f:
         try:
             return json.load(f)
-        except:
+        except Exception:
             return default_settings
 
 def save_settings(new_settings):
     with open(SETTINGS_FILE, 'w', encoding='utf-8') as f:
         json.dump(new_settings, f, indent=4)
 
+# --- GRAPH API REQUEST HELPER ---
+_RETRY_STATUSES = {429, 503}
+_MAX_RETRIES = 3
+
+def _graph_request(method, url, **kwargs):
+    """Thin wrapper around requests.request with retry for 429/503.
+
+    Retries up to _MAX_RETRIES times when Graph API signals rate limiting
+    (429) or transient unavailability (503), honouring the Retry-After header
+    when present.  A default timeout of 30 s is injected if the caller does
+    not supply one.  File-upload calls that pass an open stream as data=
+    should use requests.put() directly, since a stream cannot be re-read.
+    """
+    kwargs.setdefault("timeout", 30)
+    for attempt in range(_MAX_RETRIES):
+        res = requests.request(method, url, **kwargs)
+        if res.status_code not in _RETRY_STATUSES:
+            return res
+        if attempt < _MAX_RETRIES - 1:  # Don't sleep after the final attempt
+            retry_after = int(res.headers.get("Retry-After", 2 ** attempt))
+            time.sleep(min(retry_after, 60))
+    return res  # Return last response after exhausting retries
+
 settings = load_settings()
 CLIENT_ID = settings.get("client_id")
 TENANT_ID = settings.get("tenant_id")
@@ -675,6 +698,7 @@ class SharePointApp(wx.Frame):
         self.tree_root = None
         self.is_navigating_back = False
         self.active_edits = {} # item_id -> { "name": name, "event": Event, "waiting": bool }
+        self._edits_lock = threading.Lock()
         self.favorites = settings.get("favorites", [])
         self.fav_visible = settings.get("fav_visible", True)
         self.sort_col = 0 # Default (Navn)
@@ -708,7 +732,7 @@ class SharePointApp(wx.Frame):
             try:
                 self.msal_app = msal.PublicClientApplication(CLIENT_ID, authority=AUTHORITY)
             except Exception as e:
-                print(f"MSAL Init Error: {e}")
+                logger.error(f"MSAL Init Error: {e}")
         
         self.InitUI()
         self.Centre()
@@ -737,7 +761,7 @@ class SharePointApp(wx.Frame):
         if kwargs:
             try:
                 return text.format(**kwargs)
-            except:
+            except Exception:
                 pass
         return text
 
@@ -1170,7 +1194,7 @@ class SharePointApp(wx.Frame):
             status_text = "Sletter" if self.lang == "da" else "Deleting"
             self.set_status(f"{status_text} {count+1}/{total}: '{item['name']}'...")
             url = f"https://graph.microsoft.com/v1.0/drives/{item['drive_id']}/items/{item['id']}"
-            res = requests.delete(url, headers=self.headers)
+            res = _graph_request("DELETE", url, headers=self.headers, timeout=30)
             if res.status_code in [204, 200]:
                 count += 1
             else:
@@ -1197,7 +1221,7 @@ class SharePointApp(wx.Frame):
         url = f"https://graph.microsoft.com/v1.0/drives/{drive_id}/items/{parent_id}:/{filename}:/content"
         try:
             with open(local_path, 'rb') as f:
-                res = requests.put(url, headers=self.headers, data=f)
+                res = requests.put(url, headers=self.headers, data=f, timeout=120)
             if res.status_code in [200, 201]:
                 self.set_status(self.get_txt("msg_upload_success", name=filename))
                 self._refresh_current_view()
@@ -1238,7 +1262,7 @@ class SharePointApp(wx.Frame):
     def _create_folder_sync(self, name, drive_id, parent_id):
         url = f"https://graph.microsoft.com/v1.0/drives/{drive_id}/items/{parent_id}/children"
         body = {"name": name, "folder": {}, "@microsoft.graph.conflictBehavior": "rename"}
-        res = requests.post(url, headers=self.headers, json=body)
+        res = _graph_request("POST", url, headers=self.headers, json=body, timeout=30)
         if res.status_code in [200, 201]:
             return res.json().get('id')
         return None
@@ -1248,7 +1272,7 @@ class SharePointApp(wx.Frame):
         filename = os.path.basename(local_path)
         url = f"https://graph.microsoft.com/v1.0/drives/{drive_id}/items/{parent_id}:/{filename}:/content"
         with open(local_path, 'rb') as f:
-            requests.put(url, headers=self.headers, data=f)
+            requests.put(url, headers=self.headers, data=f, timeout=120)
 
     def on_new_folder_clicked(self, event):
         if not self.current_drive_id: return
@@ -1282,7 +1306,7 @@ class SharePointApp(wx.Frame):
         self.set_status(f"{self.get_txt('msg_rename')}...")
         url = f"https://graph.microsoft.com/v1.0/drives/{item['drive_id']}/items/{item['id']}"
         body = {"name": new_name}
-        res = requests.patch(url, headers=self.headers, json=body)
+        res = _graph_request("PATCH", url, headers=self.headers, json=body, timeout=30)
         if res.status_code in [200, 201]:
             self.set_status(self.get_txt("msg_success"))
             self._refresh_current_view()
@@ -1303,7 +1327,7 @@ class SharePointApp(wx.Frame):
             with wx.DirDialog(self, self.get_txt("msg_select_folder"), style=wx.DD_DEFAULT_STYLE | wx.DD_DIR_MUST_EXIST) as dd:
                 if dd.ShowModal() == wx.ID_OK:
                     parent_path = dd.GetPath()
-                    dest_path = os.path.join(parent_path, item['name'])
+                    dest_path = os.path.join(parent_path, os.path.basename(item['name']))
                     threading.Thread(target=self._download_folder_bg_task, args=(item, dest_path), daemon=True).start()
 
     def _download_file_bg_task(self, item, dest_path):
@@ -1319,7 +1343,7 @@ class SharePointApp(wx.Frame):
 
     def _download_file_sync_call(self, drive_id, item_id, dest_path):
         url = f"https://graph.microsoft.com/v1.0/drives/{drive_id}/items/{item_id}/content"
-        res = requests.get(url, headers=self.headers)
+        res = _graph_request("GET", url, headers=self.headers, timeout=30)
         if res.status_code == 200:
             with open(dest_path, 'wb') as f:
                 f.write(res.content)
@@ -1338,12 +1362,12 @@ class SharePointApp(wx.Frame):
             
         url = f"https://graph.microsoft.com/v1.0/drives/{drive_id}/items/{folder_id}/children"
         while url:
-            res = requests.get(url, headers=self.headers)
+            res = _graph_request("GET", url, headers=self.headers, timeout=30)
             if res.status_code == 200:
                 res_data = res.json()
                 items = res_data.get('value', [])
                 for item in items:
-                    item_path = os.path.join(local_dir, item['name'])
+                    item_path = os.path.join(local_dir, os.path.basename(item['name']))
                     if 'folder' in item:
                         self._download_folder_recursive_sync(drive_id, item['id'], item_path)
                     else:
@@ -1382,7 +1406,8 @@ class SharePointApp(wx.Frame):
         wx.CallAfter(_do)
 
     def on_done_editing_clicked(self, event):
-        waiting_files = [fid for fid, d in self.active_edits.items() if d.get("waiting")]
+        with self._edits_lock:
+            waiting_files = [fid for fid, d in self.active_edits.items() if d.get("waiting")]
         if not waiting_files:
             return
             
@@ -1666,7 +1691,7 @@ class SharePointApp(wx.Frame):
                 self.headers = {'Authorization': f'Bearer {self.access_token}'}
                 return True
         except Exception as e:
-            print(f"Token refresh error: {e}")
+            logger.error(f"Token refresh error: {e}")
             
         self.set_status(self.get_txt("status_login_needed"))
         return False
@@ -1715,9 +1740,9 @@ class SharePointApp(wx.Frame):
         self.pulse_gauge(True)
         all_sites = []
         url = "https://graph.microsoft.com/v1.0/sites?search=*"
-        
+
         while url:
-            res = requests.get(url, headers=self.headers)
+            res = _graph_request("GET", url, headers=self.headers, timeout=30)
             if res.status_code == 200:
                 data = res.json()
                 all_sites.extend(data.get('value', []))
@@ -1783,7 +1808,7 @@ class SharePointApp(wx.Frame):
             url = f"https://graph.microsoft.com/v1.0/drives/{data['drive_id']}/items/{data['id']}/children"
         
         while url:
-            res = requests.get(url, headers=self.headers)
+            res = _graph_request("GET", url, headers=self.headers, timeout=30)
             if res.status_code == 200:
                 res_data = res.json()
                 all_children.extend(res_data.get('value', []))
@@ -1906,7 +1931,7 @@ class SharePointApp(wx.Frame):
             
         first_chunk = True
         while url:
-            res = requests.get(url, headers=self.headers)
+            res = _graph_request("GET", url, headers=self.headers, timeout=30)
             if res.status_code != 200: break
             
             res_data = res.json()
@@ -2073,7 +2098,7 @@ class SharePointApp(wx.Frame):
                             idx = self.image_list.Add(bmp)
                             self.ext_icons[ext] = idx
                             return idx
-        except:
+        except Exception:
             pass
 
         self.ext_icons[ext] = self.idx_file
@@ -2231,12 +2256,16 @@ class SharePointApp(wx.Frame):
         item_id = item['id']
         file_name = item['name']
         drive_id = item['drive_id']
-        
-        if item_id in self.active_edits:
+
+        with self._edits_lock:
+            already_editing = item_id in self.active_edits
+            at_limit = len(self.active_edits) >= 10
+
+        # UI dialogs are called outside the lock to avoid holding it during blocking calls
+        if already_editing:
             self.show_info(f"'{file_name}' er allerede ved at blive redigeret.", wx.ICON_INFORMATION)
             return
-
-        if len(self.active_edits) >= 10:
+        if at_limit:
             wx.MessageBox("Du kan kun have 10 filer åbne til redigering ad gangen.", "Maksimum grænse nået", wx.OK | wx.ICON_WARNING)
             return
 
@@ -2273,7 +2302,8 @@ class SharePointApp(wx.Frame):
         if not self.ensure_valid_token(): return
         
         edit_event = threading.Event()
-        self.active_edits[item_id] = {"name": file_name, "event": edit_event, "waiting": False}
+        with self._edits_lock:
+            self.active_edits[item_id] = {"name": file_name, "event": edit_event, "waiting": False}
         self.update_edit_ui()
         
         try:
@@ -2290,7 +2320,7 @@ class SharePointApp(wx.Frame):
 
             # 2. Download
             self.set_status(self.get_txt("msg_fetching_file", name=file_name))
-            res = requests.get(f"{base_url}/content", headers=self.headers)
+            res = _graph_request("GET", f"{base_url}/content", headers=self.headers, timeout=30)
             if res.status_code != 200:
                 raise Exception(f"{self.get_txt('msg_unknown_error')}: {res.status_code}")
             
@@ -2327,7 +2357,7 @@ class SharePointApp(wx.Frame):
             
             # Checkout
             is_checked_out = False
-            checkout_res = requests.post(f"{base_url}/checkout", headers=self.headers)
+            checkout_res = _graph_request("POST", f"{base_url}/checkout", headers=self.headers, timeout=30)
             if checkout_res.status_code in [200, 201, 204]:
                 is_checked_out = True
                 logger.info(f"Fil {file_name} udtjekket succesfuldt.")
@@ -2360,13 +2390,15 @@ class SharePointApp(wx.Frame):
             else:
                 self.set_status(self.get_txt("msg_waiting_for_file", name=file_name))
                 edit_event.clear()
-                self.active_edits[item_id]["waiting"] = True
+                with self._edits_lock:
+                    self.active_edits[item_id]["waiting"] = True
                 self.update_edit_ui()
-                
+
                 edit_event.wait()
-                
-                if item_id in self.active_edits:
-                    self.active_edits[item_id]["waiting"] = False
+
+                with self._edits_lock:
+                    if item_id in self.active_edits:
+                        self.active_edits[item_id]["waiting"] = False
                 self.update_edit_ui()
 
             # 4. Tjek om noget er ændret
@@ -2387,7 +2419,7 @@ class SharePointApp(wx.Frame):
                 
                 if is_checked_out:
                     logger.info(f"Annullerer udtjekning (discardCheckout) for {file_name}...")
-                    res = requests.post(f"{base_url}/discardCheckout", headers=self.headers)
+                    res = _graph_request("POST", f"{base_url}/discardCheckout", headers=self.headers, timeout=30)
                     if res.status_code in [200, 204]:
                         is_checked_out = False
             else:
@@ -2395,14 +2427,14 @@ class SharePointApp(wx.Frame):
                 logger.info(f"Ændring fundet! Uploader {file_name}...")
                 self.set_status(self.get_txt("msg_updating_changes"))
                 with open(local_path, 'rb') as f:
-                    upload_res = requests.put(f"{base_url}/content", headers=self.headers, data=f)
+                    upload_res = requests.put(f"{base_url}/content", headers=self.headers, data=f, timeout=120)
                     if upload_res.status_code not in [200, 201]:
                         raise Exception(f"{self.get_txt('msg_update_failed_code', code=upload_res.status_code)}")
 
                 # 6. Checkin (Kun hvis vi faktisk uploadede noget)
                 if is_checked_out:
                     self.set_status(self.get_txt("msg_checking_in", name=file_name))
-                    res = requests.post(f"{base_url}/checkin", headers=self.headers, json={"comment": "SP Explorer Edit"})
+                    res = _graph_request("POST", f"{base_url}/checkin", headers=self.headers, json={"comment": "SP Explorer Edit"}, timeout=30)
                     if res.status_code in [200, 201, 204]:
                         is_checked_out = False
 
@@ -2410,7 +2442,7 @@ class SharePointApp(wx.Frame):
             try:
                 os.remove(local_path)
                 os.rmdir(working_dir)
-            except:
+            except Exception:
                 pass
                 
             self.set_status(self.get_txt("msg_update_success", name=file_name))
@@ -2424,10 +2456,11 @@ class SharePointApp(wx.Frame):
             if is_checked_out:
                 # Emergency cleanup hvis vi stadig har fat i filen (f.eks. ved crash eller afbrydelse)
                 logger.info(f"Rydder op: Kalder discardCheckout for {file_name}...")
-                requests.post(f"{base_url}/discardCheckout", headers=self.headers)
+                _graph_request("POST", f"{base_url}/discardCheckout", headers=self.headers, timeout=30)
                 
-            if item_id in self.active_edits:
-                del self.active_edits[item_id]
+            with self._edits_lock:
+                if item_id in self.active_edits:
+                    del self.active_edits[item_id]
             self.update_edit_ui()
 
 if __name__ == "__main__":

tests/test_review_fixes.py

@@ -221,5 +221,281 @@ class TestIsBreakcrumbRemoved(unittest.TestCase):
         self.assertIn("tree_item", sig.parameters)
 
 
+# ---------------------------------------------------------------------------
+# Task 7: bare except → except Exception, print → logger, basename sanitization
+# ---------------------------------------------------------------------------
+
+class TestTask7BareExcept(unittest.TestCase):
+    """Verify that bare except: clauses have been replaced with except Exception:."""
+
+    def _get_source_lines(self):
+        return inspect.getsource(sb).splitlines()
+
+    def test_no_bare_except_in_load_settings(self):
+        """7a: load_settings() uses except Exception, not bare except."""
+        source = inspect.getsource(sb.load_settings)
+        self.assertNotIn("except:", source,
+            "load_settings still has a bare except:")
+
+    def test_no_bare_except_in_get_txt(self):
+        """7a: get_txt() uses except Exception, not bare except."""
+        source = inspect.getsource(sb.SharePointApp.get_txt)
+        self.assertNotIn("except:", source,
+            "get_txt still has a bare except:")
+
+    def test_no_bare_except_in_get_icon_idx(self):
+        """7a: get_icon_idx_for_file() uses except Exception, not bare except."""
+        source = inspect.getsource(sb.SharePointApp.get_icon_idx_for_file)
+        self.assertNotIn("except:", source,
+            "get_icon_idx_for_file still has a bare except:")
+
+    def test_no_bare_except_in_process_file(self):
+        """7a: process_file() cleanup block uses except Exception, not bare except."""
+        source = inspect.getsource(sb.SharePointApp.process_file)
+        self.assertNotIn("except:", source,
+            "process_file still has a bare except: in cleanup block")
+
+    def test_no_print_in_msal_init(self):
+        """7b: MSAL init error uses logger, not print()."""
+        source = inspect.getsource(sb.SharePointApp.__init__)
+        self.assertNotIn('print(f"MSAL Init Error', source,
+            "__init__ still uses print() for MSAL Init Error")
+
+    def test_no_print_in_ensure_valid_token(self):
+        """7b: ensure_valid_token() uses logger, not print()."""
+        source = inspect.getsource(sb.SharePointApp.ensure_valid_token)
+        self.assertNotIn('print(f"Token refresh error', source,
+            "ensure_valid_token still uses print() for token error")
+
+    def test_basename_in_download_folder_recursive(self):
+        """7c: _download_folder_recursive_sync uses os.path.basename on item name."""
+        source = inspect.getsource(sb.SharePointApp._download_folder_recursive_sync)
+        self.assertIn("os.path.basename", source,
+            "_download_folder_recursive_sync does not sanitize item['name'] with basename")
+
+    def test_basename_in_on_download_clicked(self):
+        """7c: on_download_clicked uses os.path.basename when building dest_path for folders."""
+        source = inspect.getsource(sb.SharePointApp.on_download_clicked)
+        self.assertIn("os.path.basename", source,
+            "on_download_clicked does not sanitize item['name'] with basename for folder downloads")
+
+
+# ---------------------------------------------------------------------------
+# Task 8: all requests.* calls must carry a timeout= parameter
+# ---------------------------------------------------------------------------
+
+class TestNetworkTimeouts(unittest.TestCase):
+    """
+    Every requests.get/post/put/patch/delete call must include timeout=
+    so that background threads cannot hang indefinitely on a stalled network.
+    """
+
+    def _calls_missing_timeout(self):
+        """
+        Return a list of (line_number, line_text) for every requests.*()
+        call in the source file that is missing a timeout= argument.
+
+        Strategy: single-line calls are the norm in this codebase.  We look
+        for lines that contain 'requests.METHOD(' and do NOT also contain
+        'timeout='.  Lines that contain 'timeout=' anywhere on the same line
+        are considered compliant.
+        """
+        import re
+        src_path = os.path.join(
+            os.path.dirname(os.path.dirname(os.path.abspath(__file__))),
+            "sharepoint_browser.py"
+        )
+        # Matches real call sites: assignment or standalone call (not docstrings)
+        pattern = re.compile(
+            r'(=\s*|^\s*)requests\.(get|post|put|patch|delete)\('
+        )
+        missing = []
+        with open(src_path, encoding='utf-8') as fh:
+            for lineno, line in enumerate(fh, 1):
+                stripped = line.lstrip()
+                # Skip comment lines and docstring prose (lines that are plain text)
+                if stripped.startswith('#'):
+                    continue
+                if pattern.search(line) and 'timeout=' not in line:
+                    missing.append((lineno, line.rstrip()))
+        return missing
+
+    def test_all_requests_calls_have_timeout(self):
+        """Task 8: No requests.* call is missing a timeout= parameter."""
+        missing = self._calls_missing_timeout()
+        if missing:
+            details = "\n".join(f"  line {n}: {txt}" for n, txt in missing)
+            self.fail(
+                f"{len(missing)} requests call(s) are missing timeout=:\n{details}"
+            )
+
+
+# ---------------------------------------------------------------------------
+# Task 9: _graph_request helper — retry on 429/503 with Retry-After support
+# ---------------------------------------------------------------------------
+
+class TestGraphRequest(unittest.TestCase):
+    """Unit tests for the _graph_request() module-level helper."""
+
+    def test_helper_exists(self):
+        """Task 9: _graph_request function is defined at module level."""
+        self.assertTrue(
+            callable(getattr(sb, "_graph_request", None)),
+            "_graph_request is not defined in sharepoint_browser"
+        )
+
+    def test_success_on_first_attempt(self):
+        """Task 9: Returns immediately when first response is 200."""
+        mock_resp = MagicMock()
+        mock_resp.status_code = 200
+        with patch("sharepoint_browser.requests.request", return_value=mock_resp) as mock_req:
+            result = sb._graph_request("GET", "https://example.com/", headers={})
+        self.assertEqual(result.status_code, 200)
+        self.assertEqual(mock_req.call_count, 1)
+
+    def test_retries_on_429(self):
+        """Task 9: Retries when response is 429 (rate limited)."""
+        responses = [
+            MagicMock(status_code=429, headers={"Retry-After": "0"}),
+            MagicMock(status_code=429, headers={"Retry-After": "0"}),
+            MagicMock(status_code=200, headers={}),
+        ]
+        with patch("sharepoint_browser.requests.request", side_effect=responses) as mock_req:
+            with patch("sharepoint_browser.time.sleep"):
+                result = sb._graph_request("GET", "https://example.com/", headers={})
+        self.assertEqual(result.status_code, 200)
+        self.assertEqual(mock_req.call_count, 3)
+
+    def test_retries_on_503(self):
+        """Task 9: Retries when response is 503 (service unavailable)."""
+        responses = [
+            MagicMock(status_code=503, headers={}),
+            MagicMock(status_code=200, headers={}),
+        ]
+        with patch("sharepoint_browser.requests.request", side_effect=responses) as mock_req:
+            with patch("sharepoint_browser.time.sleep"):
+                result = sb._graph_request("POST", "https://example.com/", headers={})
+        self.assertEqual(result.status_code, 200)
+        self.assertEqual(mock_req.call_count, 2)
+
+    def test_returns_last_response_after_max_retries(self):
+        """Task 9: Returns last 429 response when all retries are exhausted."""
+        resp_429 = MagicMock(status_code=429, headers={"Retry-After": "0"})
+        responses = [resp_429] * sb._MAX_RETRIES
+        with patch("sharepoint_browser.requests.request", side_effect=responses):
+            with patch("sharepoint_browser.time.sleep"):
+                result = sb._graph_request("GET", "https://example.com/", headers={})
+        self.assertEqual(result.status_code, 429)
+
+    def test_respects_retry_after_header(self):
+        """Task 9: sleep() is called with the Retry-After value from the response."""
+        responses = [
+            MagicMock(status_code=429, headers={"Retry-After": "5"}),
+            MagicMock(status_code=200, headers={}),
+        ]
+        with patch("sharepoint_browser.requests.request", side_effect=responses):
+            with patch("sharepoint_browser.time.sleep") as mock_sleep:
+                sb._graph_request("GET", "https://example.com/", headers={})
+        mock_sleep.assert_called_once_with(5)
+
+    def test_default_timeout_injected(self):
+        """Task 9: timeout=30 is injected when caller does not provide one."""
+        mock_resp = MagicMock(status_code=200, headers={})
+        with patch("sharepoint_browser.requests.request", return_value=mock_resp) as mock_req:
+            sb._graph_request("GET", "https://example.com/", headers={})
+        _, kwargs = mock_req.call_args
+        self.assertEqual(kwargs.get("timeout"), 30)
+
+    def test_caller_timeout_not_overridden(self):
+        """Task 9: Explicit timeout from caller is not overwritten by the helper."""
+        mock_resp = MagicMock(status_code=200, headers={})
+        with patch("sharepoint_browser.requests.request", return_value=mock_resp) as mock_req:
+            sb._graph_request("GET", "https://example.com/", headers={}, timeout=60)
+        _, kwargs = mock_req.call_args
+        self.assertEqual(kwargs.get("timeout"), 60)
+
+    def test_max_retries_constant_exists(self):
+        """Task 9: _MAX_RETRIES constant is defined."""
+        self.assertTrue(
+            hasattr(sb, "_MAX_RETRIES"),
+            "_MAX_RETRIES constant not found in sharepoint_browser"
+        )
+
+    def test_no_sleep_after_final_retry(self):
+        """Fix #1: sleep() is NOT called after the last exhausted attempt."""
+        resp_429 = MagicMock(status_code=429, headers={"Retry-After": "0"})
+        responses = [resp_429] * sb._MAX_RETRIES
+        with patch("sharepoint_browser.requests.request", side_effect=responses):
+            with patch("sharepoint_browser.time.sleep") as mock_sleep:
+                sb._graph_request("GET", "https://example.com/", headers={})
+        # sleep should be called for the first N-1 failures, NOT the last one
+        self.assertEqual(
+            mock_sleep.call_count,
+            sb._MAX_RETRIES - 1,
+            f"sleep() called {mock_sleep.call_count} times; expected {sb._MAX_RETRIES - 1} "
+            f"(no sleep after the final failed attempt)"
+        )
+
+
+# ---------------------------------------------------------------------------
+# Task 10: threading.Lock for active_edits compound operations
+# ---------------------------------------------------------------------------
+
+class TestActiveEditsLock(unittest.TestCase):
+    """Verify that _edits_lock exists and guards all compound active_edits operations."""
+
+    def test_edits_lock_declared_in_init(self):
+        """Task 10: SharePointApp.__init__ creates self._edits_lock."""
+        source = inspect.getsource(sb.SharePointApp.__init__)
+        self.assertIn("_edits_lock", source,
+            "__init__ does not declare _edits_lock")
+
+    def test_edits_lock_is_threading_lock(self):
+        """Task 10: _edits_lock initialisation uses threading.Lock()."""
+        source = inspect.getsource(sb.SharePointApp.__init__)
+        self.assertIn("threading.Lock()", source,
+            "__init__ does not initialise _edits_lock with threading.Lock()")
+
+    def test_open_file_uses_lock(self):
+        """Task 10: open_file() acquires _edits_lock before checking active_edits."""
+        source = inspect.getsource(sb.SharePointApp.open_file)
+        self.assertIn("_edits_lock", source,
+            "open_file does not use _edits_lock")
+
+    def test_process_file_uses_lock(self):
+        """Task 10: process_file() acquires _edits_lock when writing active_edits."""
+        source = inspect.getsource(sb.SharePointApp.process_file)
+        self.assertIn("_edits_lock", source,
+            "process_file does not use _edits_lock")
+
+    def test_process_file_lock_on_initial_assign(self):
+        """Task 10: active_edits[item_id] = ... assignment is inside a lock block."""
+        source = inspect.getsource(sb.SharePointApp.process_file)
+        # Check lock wraps the initial dict assignment
+        lock_idx = source.find("_edits_lock")
+        assign_idx = source.find('self.active_edits[item_id] = ')
+        self.assertGreater(assign_idx, 0,
+            "active_edits assignment not found in process_file")
+        # The lock must appear before the assignment
+        self.assertLess(lock_idx, assign_idx,
+            "_edits_lock must appear before the active_edits assignment in process_file")
+
+    def test_process_file_lock_on_delete(self):
+        """Task 10: del active_edits[item_id] is inside a lock block in process_file."""
+        source = inspect.getsource(sb.SharePointApp.process_file)
+        self.assertIn("del self.active_edits[item_id]", source,
+            "del active_edits[item_id] not found in process_file")
+        # Count lock usages — there should be at least 2
+        lock_count = source.count("_edits_lock")
+        self.assertGreaterEqual(lock_count, 2,
+            f"Expected at least 2 uses of _edits_lock in process_file, found {lock_count}")
+
+    def test_on_done_editing_uses_lock(self):
+        """Task 10: on_done_editing_clicked acquires lock for active_edits iteration."""
+        source = inspect.getsource(sb.SharePointApp.on_done_editing_clicked)
+        self.assertIn("_edits_lock", source,
+            "on_done_editing_clicked does not use _edits_lock")
+
+
 if __name__ == "__main__":
     unittest.main(verbosity=2)