fmt-workspaces-test: one fault case per fixture package, root included (improvise-90ea)

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VdfEGXA7aJ6ftMsCc9PJze

scripts/fmt-workspaces-test.sh

@@ -76,36 +76,37 @@ run_case() {
 scaffold
 run_case "both workspaces clean is a pass" 0 "$work/repo"
 
-# The load-bearing case. `cargo fmt --all` at the outer root cannot reach this
-# file, and `cargo fmt -p inner-pkg` from the outer root exits 1 saying `not a
-# member of the workspace` -- the usage error this whole script exists to split
-# from a real verdict.
+# One fault case PER PACKAGE, enumerated from the fixture rather than
+# hand-picked: three hand-picked shapes each missed a rival, and the fourth
+# missed the root package itself (improvise-90ea). Reasoning:
+# context/test-evidence/tooling.md. The enumeration is a find over
+# `[package]` manifests, deliberately NOT the script's own `[workspace]` +
+# `cargo metadata` discovery, which is the thing under test.
 scaffold
-printf '%s' "$DIRTY" > "$work/repo/nested/src/lib.rs"
-if run_case "a fault in the NESTED workspace is reported" 1 "$work/repo"; then
-  case "$OUT" in
-    *nested/src/lib.rs*) ok "  and the nested file is named" ;;
-    *) bad "  and the nested file is named" "output did not name it: ${OUT:0:300}" ;;
-  esac
+pkg_manifests=()
+while IFS= read -r m; do pkg_manifests+=("$m"); done < <(
+  cd "$work/repo" && grep -rl --include=Cargo.toml '^\[package\]' . | sort)
+# An empty or shrunken enumeration would make the loop below vacuous.
+if [ "${#pkg_manifests[@]}" = 3 ]; then
+  ok "the fixture enumerates all three packages (root, member, nested)"
+else
+  bad "the fixture enumerates all three packages" "found: ${pkg_manifests[*]:-none}"
 fi
-
-scaffold
-printf '%s' "$DIRTY" > "$work/repo/a/src/lib.rs"
-if run_case "a fault in the OUTER workspace is reported" 1 "$work/repo"; then
-  case "$OUT" in
-    *a/src/lib.rs*) ok "  and the outer file is named" ;;
-    *) bad "  and the outer file is named" "output did not name it: ${OUT:0:300}" ;;
-  esac
-  # The rival: spelling the per-root check `--all` instead of `-p <members>`
-  # walks PAST the nested workspace boundary (measured), so the OUTER file is
-  # reported a second time under the inner root. Counting is what sees that.
-  n="$(printf '%s\n' "$OUT" | grep -c 'a/src/lib.rs')"
-  if [ "$n" = 1 ]; then
-    ok "  and it is named ONCE -- no root reaches past its own boundary"
-  else
-    bad "  and it is named ONCE" "named $n times; a root is walking past its boundary"
+for m in "${pkg_manifests[@]}"; do
+  rel="$(dirname "${m#./}")/src/lib.rs"; rel="${rel#./}"
+  scaffold
+  printf '%s' "$DIRTY" > "$work/repo/$rel"
+  if run_case "a fault in $rel is reported" 1 "$work/repo"; then
+    # Counting, not matching: `--all` for `-p` walks PAST the nested boundary
+    # (measured) and names an outer file a second time under the inner root.
+    n="$(printf '%s\n' "$OUT" | grep -cF "$work/repo/$rel")"
+    if [ "$n" = 1 ]; then
+      ok "  and $rel is named exactly once"
+    else
+      bad "  and $rel is named exactly once" "named $n times; output: ${OUT:0:300}"
+    fi
   fi
-fi
+done
 
 # A usage error must NOT wear a formatting failure's exit code. This is the
 # whole ticket: `cargo fmt -p opfs-contract` from the repo root exits 1.