Fix timestamp issue in test_check_source_is_newer_when_using_jupytext_sync (#1461)

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: mwouts <[email protected]>

Author: Copilot

CHANGELOG.md

@@ -1,9 +1,12 @@
 Jupytext ChangeLog
 ==================
 
-1.18.0.post1 (unreleased)
+1.18.1 (2025-10-19)
 -------------------
 
+**Fixed**
+- Fixed test `test_check_source_is_newer_when_using_jupytext_sync` to work reliably on systems with low filesystem timestamp resolution ([#1460](https://github.com/mwouts/jupytext/issues/1460))
+
 **Changed**
 - We now use `pixi` to maintain the local Python environments used for developing and testing Jupytext.
 

src/jupytext/version.py

@@ -1,4 +1,4 @@
 """Jupytext's version number"""
 
 # Must match [N!]N(.N)*[{a|b|rc}N][.postN][.devN], cf. PEP 440
-__version__ = "1.18.0.post1"
+__version__ = "1.18.1"

tests/functional/cli/test_source_is_newer.py

@@ -2,6 +2,7 @@
 Here we test the --check-source-is-newer option of the jupytext CLI
 """
 
+import os
 from jupytext import cli
 from jupytext import write
 
@@ -45,6 +46,10 @@ def test_check_source_is_newer_when_using_jupytext_sync(tmp_path, python_noteboo
     # Running sync on the .py file works as .py is always more recent after a --sync operation
     cli.jupytext([str(tmp_py), "--sync", "--check-source-is-newer"])
 
+    # Make .ipynb slightly older again to ensure .py is newer
+    stat = os.stat(tmp_ipynb)
+    os.utime(tmp_ipynb, (stat.st_atime, stat.st_mtime - 1))
+
     # Now, trying to sync the .ipynb to .py raises an error because .ipynb is older than .py
     with pytest.raises(ValueError, match=r"Source .*notebook\.ipynb.* is older than paired file .*notebook\.py.*"):
         cli.jupytext([str(tmp_ipynb), "--sync", "--check-source-is-newer"])
@@ -53,6 +58,10 @@ def test_check_source_is_newer_when_using_jupytext_sync(tmp_path, python_noteboo
     text = tmp_ipynb.read_text().replace("A short notebook", "A short notebook with a modification")
     tmp_ipynb.write_text(text)
 
+    # Make .py slightly older to ensure .ipynb is newer
+    stat = os.stat(tmp_py)
+    os.utime(tmp_py, (stat.st_atime, stat.st_mtime - 1))
+
     # Now, trying to sync the .py to .ipynb raises an error because the .py is older than the .ipynb
     with pytest.raises(ValueError, match=r"Source .*notebook\.py.* is older than paired file .*notebook\.ipynb.*"):
         cli.jupytext([str(tmp_py), "--sync", "--check-source-is-newer"])