Add BusyBox verification to test script and documentation

Co-authored-by: johndoe6345789 <224850594+johndoe6345789@users.noreply.github.com>

scripts/test.sh

@@ -2,9 +2,47 @@
 echo "SparkOS Docker Test Environment"
 echo "================================"
 echo ""
-echo "SparkOS init binary: /sparkos/rootfs/sbin/init"
+
+# Verify BusyBox is present and working
+echo "Verifying BusyBox..."
+echo "-------------------"
+if command -v busybox >/dev/null 2>&1; then
+    echo "✓ BusyBox is installed"
+    echo ""
+    echo "BusyBox version:"
+    busybox | head -n 1
+    echo ""
+    echo "BusyBox location:"
+    which busybox
+    ls -lh $(which busybox)
+    echo ""
+    echo "Shell (/bin/sh) is BusyBox:"
+    ls -lh /bin/sh
+    if [ -L /bin/sh ]; then
+        echo "  → /bin/sh is a symlink to: $(readlink /bin/sh)"
+    fi
+    echo ""
+    echo "Available BusyBox applets (sample):"
+    busybox --list | head -n 20
+    echo "  ... and $(busybox --list | wc -l) total applets"
+    echo ""
+    echo "Networking applets (required for SparkOS):"
+    for cmd in udhcpc ip ifconfig ping wget; do
+        if busybox --list | grep -q "^${cmd}$"; then
+            echo "  ✓ $cmd"
+        else
+            echo "  ✗ $cmd (NOT FOUND)"
+        fi
+    done
+else
+    echo "✗ BusyBox not found!"
+    echo "  SparkOS requires BusyBox for shell and utilities"
+    exit 1
+fi
+
 echo ""
-echo "Verifying init binary..."
+echo "Verifying SparkOS init binary..."
+echo "--------------------------------"
 if [ -f /sparkos/rootfs/sbin/init ]; then
     echo "✓ Init binary exists"
     ls -lh /sparkos/rootfs/sbin/init
@@ -22,11 +60,21 @@ else
     echo "✗ Init binary not found!"
     exit 1
 fi
+
 echo ""
 echo "Root filesystem structure:"
+echo "--------------------------"
 ls -la /sparkos/rootfs/
 echo ""
-echo "SparkOS is ready for testing!"
+echo "================================"
+echo "✓ SparkOS is ready for testing!"
+echo "================================"
+echo ""
+echo "Summary:"
+echo "  - BusyBox: $(busybox | head -n 1)"
+echo "  - Init: Custom SparkOS init system"
+echo "  - Shell: BusyBox sh (/bin/sh)"
+echo "  - Networking: BusyBox udhcpc, ip, ping, wget"
 echo ""
 echo "To test the init system:"
 echo "  docker run --rm <image> /sparkos/rootfs/sbin/init --help"