Skip checkpoint-equal incremental items

tests/test_pull_incremental_pagination.py

@@ -31,6 +31,52 @@ class MockHTTPResponse:
         return headers
 
 
+def test_backup_pulls_incremental_excludes_checkpoint_timestamp(create_args, tmp_path):
+    args = create_args(include_pulls=True, incremental=True)
+    args.since = "2026-04-26T08:13:46Z"
+    repository = {"full_name": "owner/repo"}
+
+    responses = [
+        MockHTTPResponse([]),
+        MockHTTPResponse(
+            [
+                {
+                    "number": 1,
+                    "title": "already backed up",
+                    "updated_at": "2026-04-26T08:13:46Z",
+                },
+            ],
+            link_header='<https://api.github.com/repos/owner/repo/pulls?per_page=100&state=closed&page=2>; rel="next"',
+        ),
+        MockHTTPResponse(
+            [
+                {
+                    "number": 0,
+                    "title": "older pull on page 2",
+                    "updated_at": "2026-04-25T07:00:00Z",
+                }
+            ]
+        ),
+    ]
+    requests_made = []
+
+    def mock_urlopen(request, *args, **kwargs):
+        requests_made.append(request.get_full_url())
+        return responses[len(requests_made) - 1]
+
+    with patch("github_backup.github_backup.urlopen", side_effect=mock_urlopen):
+        github_backup.backup_pulls(
+            args, tmp_path, repository, "https://api.github.com/repos"
+        )
+
+    assert len(requests_made) == 2
+    assert "state=open" in requests_made[0]
+    assert "state=closed" in requests_made[1]
+    assert all("page=2" not in url for url in requests_made)
+    assert not os.path.exists(tmp_path / "pulls" / "1.json")
+    assert not os.path.exists(tmp_path / "pulls" / "0.json")
+
+
 def test_backup_pulls_incremental_stops_before_fetching_old_pages(
     create_args, tmp_path
 ):