diff --git a/test-wheel.bash b/test-wheel.bash
index 03dd98e..cba84a0 100755
--- a/test-wheel.bash
+++ b/test-wheel.bash
@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
 
+set -e
+
 my_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
 . "$my_dir/python.bash"
 
@@ -13,13 +15,30 @@ pip install pytest
 cleanup=true
 
 trap '
-  if [[ -n $(jobs -p) ]]; then
-    echo "→ Killing $(jobs -p)"
-    kill $(jobs -p)
-  fi
+  failed_pids=()
+  for pid in $(jobs -p); do
+    if kill -0 $pid >/dev/null 2>&1; then
+      # Background process is still running - good.
+      kill $pid
+    else
+      exit_status=$?
+      if [[ $exit_status -eq 0 ]]; then
+        echo "Background task $pid already exited with zero status."
+      else
+        echo "Background task $pid exited with nonzero status ($exit_status)."
+        failed_pids+=("$pid")
+      fi
+    fi
+  done
+
   if [[ "$cleanup" == "true" ]]; then
     echo "→ Removing $venv"; rm -rf "$venv"
   fi
+
+  if [[ ${#failed_pids[@]} -gt 0 ]]; then
+    echo "The following background processes exited with nonzero status: ${failed_pids[@]}"
+    exit 1
+  fi
   ' EXIT
 
 while [[ $# -gt 0 ]]; do
@@ -31,14 +50,15 @@ while [[ $# -gt 0 ]]; do
       shift
       ;;
     -b|--background)
-      echo "→ Launching Background Task $2 ..."
+      echo "→ Launching background task: $2"
       $2 &
+      echo "... started with PID: $!"
       sleep 5
       shift
       shift
       ;;
     -f|--foreground)
-      echo "→ Starting $2 ..."
+      echo "→ Starting foreground task: $2"
       $2
       shift
       shift
@@ -51,5 +71,3 @@ while [[ $# -gt 0 ]]; do
       ;;
   esac
 done
-
-exit 0