Fix error detection to check error value, not just key presence

- Change error detection from checking key existence to checking value
- Only treat as error if error key has non-None value
- Add test for success case with 'error': None in response
- Fixes false positive error detection when API returns success

The Pocket API returns {'error': None, 'list': {...}} for successful
responses, so we need to check the error value, not just key presence.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: digithree

pocket_to_sqlite/utils.py

@@ -126,9 +126,9 @@ def __iter__(self):
             page = response.json()
             logging.debug(f"API response keys: {list(page.keys())}")
 
-            # Check for API errors
-            if "error" in page:
-                error_msg = page.get('error', 'Unknown error')
+            # Check for API errors (error key present AND has a non-None value)
+            error_msg = page.get('error')
+            if error_msg is not None:
                 logging.error(f"API returned error: {page}")
 
                 # Handle payload too large by reducing page size

tests/test_save_pocket.py

@@ -185,6 +185,41 @@ def test_fetch_items_handles_payload_too_large():
         assert fetcher.page_size == 50  # 100 // 2
 
 
+def test_fetch_items_handles_error_none_success():
+    """Test that FetchItems handles responses with error: None as success."""
+    from unittest.mock import Mock, patch
+    
+    # Mock auth
+    auth = {
+        "pocket_consumer_key": "test_key",
+        "pocket_access_token": "test_token"
+    }
+    
+    # Mock response with error: None (this is actually success)
+    mock_response_success = Mock()
+    mock_response_success.status_code = 200
+    mock_response_success.json.return_value = {
+        "error": None,
+        "list": {"1": {"item_id": "1", "title": "Test"}}, 
+        "since": 123
+    }
+    mock_response_success.raise_for_status.return_value = None
+    
+    # Mock empty response to end iteration
+    mock_response_empty = Mock()
+    mock_response_empty.status_code = 200
+    mock_response_empty.json.return_value = {"error": None, "list": {}, "since": 124}
+    mock_response_empty.raise_for_status.return_value = None
+    
+    with patch('requests.post', side_effect=[mock_response_success, mock_response_empty]):
+        fetcher = utils.FetchItems(auth, page_size=50)
+        items = list(fetcher)
+        
+        # Should successfully fetch items despite error key being present
+        assert len(items) == 1
+        assert items[0]["item_id"] == "1"
+
+
 def test_ensure_fts_with_no_items_table():
     """Test that ensure_fts handles case when items table doesn't exist."""
     db = sqlite_utils.Database(":memory:")