open-standards/scripts/pr-touches-paths-selftest.sh

#!/usr/bin/env bash
# Self-test for pr-touches-paths.py, run by the workflow-hygiene job.
#
# A gate that decides whether tests run is itself load-bearing: a wrong `false`
# silently skips a whole workflow. These cases pin both directions and, most
# importantly, that every way of failing fails OPEN.
set -euo pipefail
cd "$(dirname "$0")/.."
G=scripts/pr-touches-paths.py
tmp=$(mktemp -d); trap 'rm -rf "$tmp"' EXIT
fail=0
check() { # name expected actual
  if [ "$2" = "$3" ]; then printf '  ok    %s\n' "$1"
  else printf '  FAIL  %s: expected %s, got %s\n' "$1" "$2" "$3"; fail=1; fi
}

# A throwaway repo, so the diffs are real git diffs and not a mock.
repo="$tmp/r"; mkdir -p "$repo/wai/wai-pack" "$repo/jcp"
git -C "$repo" init -q
git -C "$repo" config user.email t@e; git -C "$repo" config user.name t
echo x > "$repo/jcp/SPEC.md"; echo y > "$repo/wai/wai-pack/lib.rs"
git -C "$repo" add -A; git -C "$repo" commit -qm base
BASE=$(git -C "$repo" rev-parse HEAD)
echo changed > "$repo/jcp/SPEC.md"
git -C "$repo" add -A; git -C "$repo" commit -qm jcp-only
JCP=$(git -C "$repo" rev-parse HEAD)
echo changed > "$repo/wai/wai-pack/lib.rs"
git -C "$repo" add -A; git -C "$repo" commit -qm wai-too
WAI=$(git -C "$repo" rev-parse HEAD)

wf="$tmp/w.yml"
cat > "$wf" <<'Y'
on:
  pull_request:
    paths:
      - 'wai/wai-pack/**'
Y

run() { ( cd "$repo" && python3 "$OLDPWD/$G" "$1" "$2" "$3" ); }
check "a jcp-only diff does not touch a wai filter" false "$(run "$wf" "$BASE" "$JCP")"
check "a diff that touches the filter runs"          true  "$(run "$wf" "$BASE" "$WAI")"

# Every failure mode must fail OPEN.
check "a missing workflow file"      true "$(run "$tmp/nope.yml" "$BASE" "$JCP")"
check "a workflow with no filter"    true "$(printf 'on:\n  pull_request:\n' > "$tmp/nofilter.yml"; run "$tmp/nofilter.yml" "$BASE" "$JCP")"
check "an empty base sha"            true "$(run "$wf" "" "$JCP")"
check "a sha git cannot resolve"     true "$(run "$wf" "$BASE" deadbeefdeadbeefdeadbeefdeadbeefdeadbeef)"
check "too few arguments"            true "$( cd "$repo" && python3 "$OLDPWD/$G" "$wf" )"
check "an empty diff"                true "$(run "$wf" "$JCP" "$JCP")"

# `**` spans separators; `*` does not.
cat > "$tmp/star.yml" <<'Y'
on:
  pull_request:
    paths:
      - 'jcp/*.md'
Y
# Only the NESTED file changes, so `jcp/*.md` must not match it. (A top-level
# .md in the same commit would match legitimately and prove nothing — which is
# how this case failed the first time it was written.)
mkdir -p "$repo/jcp/sub"; echo z > "$repo/jcp/sub/x.md"
git -C "$repo" add -A >/dev/null; git -C "$repo" commit -qm sub >/dev/null
SUB=$(git -C "$repo" rev-parse HEAD)
check "a single star does not span a separator" false "$(run "$tmp/star.yml" "$WAI" "$SUB")"
# And it does match a file at that level, so the glob is not simply never matching.
echo z > "$repo/jcp/top.md"
git -C "$repo" add -A >/dev/null; git -C "$repo" commit -qm top >/dev/null
check "a single star matches at its own level" true "$(run "$tmp/star.yml" "$SUB" "$(git -C "$repo" rev-parse HEAD)")"

# A comment or a blank line inside a list does not end it, and a trailing comment is not
# part of a glob. (Lists with a comment used to be read only up to it, so a pull request
# touching a path after the comment was answered `false` and its tests skipped.)
cat > "$tmp/commented.yml" <<'Y'
on:
  pull_request:
    paths:
      - 'jcp/nothing-here/**'
      # a comment between entries

      - 'wai/wai-pack/**'   # and one after an entry
Y
check "a path listed after a comment and a blank line" true "$(run "$tmp/commented.yml" "$BASE" "$WAI")"
check "and the list still says false for a diff outside it" false "$(run "$tmp/commented.yml" "$BASE" "$JCP")"

[ "$fail" = 0 ] && echo "pr-touches-paths self-test: all cases pass" || { echo "pr-touches-paths self-test FAILED"; exit 1; }