Migration¶

This guide outlines how to migrate from an ad hoc "run R chunks and save outputs" approach to pytest-r-snapshot.

Keep your existing R chunks¶

If your tests already include commented fenced chunks like:

# ```{r, minimal_rtf}
# ...
# ```

you can keep them as-is. The plugin uses a compatible chunk syntax and requires only that every chunk has a unique label per file.

Instead of custom "expected output" readers, use:

r_snapshot.read_text(name="label", ext=".rtf") to load an expected snapshot
r_snapshot.assert_match_text(actual, name="label", ext=".rtf") to compare with diffs

If you already store recorded outputs under a specific root, configure the plugin:

pytest --r-snapshot=record --r-snapshot-dir=vendor/rtflite/tests/fixtures/r_outputs

With --r-snapshot-dir=..., the plugin writes snapshots under:

vendor/rtflite/tests/fixtures/r_outputs/<test_file_stem>/<name><ext>

If your existing layout differs, the simplest migration is to record once with the plugin and commit the new layout.