mmdebstrap/tests/install-busybox-based-sub-essential-system

#!/bin/sh
set -eu
export LC_ALL=C.UTF-8

trap "rm -rf /tmp/debian-chroot" EXIT INT TERM

pkgs=base-files,base-passwd,busybox,debianutils,dpkg,libc-bin,mawk,tar
# busybox --install -s will install symbolic links into the rootfs, leaving
# existing files untouched. It has to run after extraction (otherwise there is
# no busybox binary) and before first configuration
{{ CMD }} --mode=root --variant=custom \
  --include=$pkgs \
  --setup-hook='mkdir -p "$1/bin"' \
  --setup-hook='echo root:x:0:0:root:/root:/bin/sh > "$1/etc/passwd"' \
  --setup-hook='printf "root:x:0:\nmail:x:8:\nutmp:x:43:\n" > "$1/etc/group"' \
  --extract-hook='chroot "$1" busybox --install -s' \
  {{ DIST }} /tmp/debian-chroot {{ MIRROR }}
echo "$pkgs" | tr ',' '\n' >/tmp/expected
chroot /tmp/debian-chroot dpkg-query -f '${binary:Package}\n' -W \
  | comm -12 - /tmp/expected \
  | diff -u - /tmp/expected
rm /tmp/expected
for cmd in echo cat sed grep; do
  test -L /tmp/debian-chroot/bin/$cmd
  test "$(readlink /tmp/debian-chroot/bin/$cmd)" = "/usr/bin/busybox"
done
for cmd in sort tee; do
  test -L /tmp/debian-chroot/usr/bin/$cmd
  test "$(readlink /tmp/debian-chroot/usr/bin/$cmd)" = "/usr/bin/busybox"
done

# if /bin or /sbin are not symlinks, add /bin and /sbin to PATH
if [ ! -L /tmp/debian-chroot/bin ] || [ ! -L /tmp/debian-chroot/sbin ]; then
  export PATH="$PATH:/sbin:/bin"
fi
chroot /tmp/debian-chroot echo foobar \
  | chroot /tmp/debian-chroot cat \
  | chroot /tmp/debian-chroot sort \
  | chroot /tmp/debian-chroot tee /dev/null \
  | chroot /tmp/debian-chroot sed 's/foobar/blubber/' \
  | chroot /tmp/debian-chroot grep blubber >/dev/null