Running the diff-slider tests

The tests compare gix-diff with Git using data produced by diff-slider-tools. The commands below don't create or discover a corpus: they require a .sliders file and its corresponding Git repository.

Prepare the corpus once

From a diff-slider-tools checkout:

repo=gitoxide
echo https://github.com/GitoxideLabs/gitoxide >"corpus/$repo.info"
./get-corpus "$repo"
git -C "corpus/$repo.git" log --min-parents=1 --max-parents=1 --format='%P..%H' HEAD |
  ./enumerate-sliders --repo="$repo" >"corpus/$repo.sliders"

export SLIDERS_FILE="$PWD/corpus/$repo.sliders"
export SLIDER_REPOSITORY="$PWD/corpus/$repo.git"

get-corpus reads corpus/gitoxide.info and creates corpus/gitoxide.git. enumerate-sliders then reads that repository and creates corpus/gitoxide.sliders.

Optionally, see the complete upstream corpus instructions for other repositories or commit ranges.

If the corpus already exists, only set its explicit paths:

export SLIDERS_FILE=/path/to/diff-slider-tools/corpus/gitoxide.sliders
export SLIDER_REPOSITORY=/path/to/diff-slider-tools/corpus/gitoxide.git

Then run these two commands from the gitoxide root:

cargo run --package internal-tools -- create-diff-cases \
  --count 2024 \
  --sliders-file "$SLIDERS_FILE" \
  --worktree-dir "$SLIDER_REPOSITORY" \
  --destination-dir gix-diff/tests/fixtures/

cargo test -p gix-diff slider::baseline -- --nocapture

--count limits how many slider records are read; lower it for a quicker run. With the current gitoxide corpus, --count 2024 produces 3,094 cases after duplicate blob pairs are removed.

The default report prints all mismatch categories without failing. Set GIX_DIFF_SLIDER_STRICT=1 to require a non-empty external baseline and fail on any mismatch. The small built-in baseline always runs strictly.

Inspect one case

Copy a primary baseline filename from the report and select it explicitly:

GIX_DIFF_SLIDER_CASE='<old>-<new>.myers.baseline' \
  cargo test -p gix-diff --test diff blob::slider::baseline -- --exact --nocapture

The selector must match the complete filename, including the algorithm and .baseline suffix. Inspection replaces the aggregate report with a StrComparison between the two unified diffs: Gitoxide with slider heuristics on the left and Git with the indent heuristic on the right. Matching output is reported explicitly. A mismatch doesn't fail inspection; an empty, missing, or ambiguous selection does.

GIX_DIFF_SLIDER_CASE cannot be combined with GIX_DIFF_SLIDER_STRICT. Only the selected external case is loaded and diffed when GIX_DIFF_SLIDER_CASE is given.