log more to identify what failed

parallel_test.sh

@@ -20,9 +20,9 @@ fi
 
 # run tests
 for t in "${tests[@]}"; do
-    echo "Starting test ${t}"
     ./node_modules/.bin/mocha "test/${t}.js" > "logs/${t}.log" 2>&1 &
     test_pids+=("$!")
+    echo "Starting test ${t} with pid ${test_pids[-1]}"
     test_logs+=("logs/${t}.log")
 done
 
@@ -40,7 +40,10 @@ tail_pid=$!
 fail=0
 echo "Waiting for jobs to finish"
 for pid in "${test_pids[@]}"; do
-    wait $pid || let "fail+=1"
+    if ! wait $pid; then
+        let "fail+=1"
+        echo "$pid failed"
+    fi
 done
 
 kill -9 "${tail_pid}"