diff --git a/tests/run-bats.sh b/tests/run-bats.sh
index 9059661..8aff317 100755
--- a/tests/run-bats.sh
+++ b/tests/run-bats.sh
@@ -39,11 +39,12 @@ fi
 SCRATCH_ROOT="$(mktemp -d)"
 trap 'rm -rf "$SCRATCH_ROOT"' EXIT
 
-# A failing test is the normal case a CI runner must handle, and a failing
-# background job makes `wait`/`wait -n` return non-zero -- under `set -e` that
-# would abort the script right here, before the per-file report below ever
-# runs. Every wait in this dispatcher is therefore explicitly guarded.
-JOBS="$(nproc 2>/dev/null || echo 4)"
+# Batches (not a rolling pool) because a bounded rolling pool needs `wait -n`,
+# which is bash 4.3+ and this script is explicitly bash-3.2-safe like
+# run-tests.sh; plain `wait` -- waiting for every job in the current batch --
+# is available since ancient bash. `getconf` over `nproc` for the same
+# reason: `nproc` doesn't exist on macOS.
+JOBS="$(getconf _NPROCESSORS_ONLN 2>/dev/null || echo 4)"
 running=0
 i=0
 for f in "${TEST_FILES[@]}"; do
@@ -51,11 +52,11 @@ for f in "${TEST_FILES[@]}"; do
     ( "$BATS" "$f" >"$SCRATCH_ROOT/$i.log" 2>&1; echo $? >"$SCRATCH_ROOT/$i.status" ) &
     running=$((running + 1))
     if [[ "$running" -ge "$JOBS" ]]; then
-        wait -n || true
-        running=$((running - 1))
+        wait
+        running=0
     fi
 done
-wait || true
+wait
 
 FAIL=0
 TOTAL_OK=0