test

#!/bin/sh
# -*- sh -*-
# vim: syntax=sh
# code: language=shellscript

# Copyright (c) 2023 Michael Federczuk
# SPDX-License-Identifier: MPL-2.0 AND Apache-2.0

# TODO: can this be done better with LXC?

case "$-" in
	(*'i'*)
		\command printf 'script was called interactively\n' >&2
		return 124
		;;
esac

set -o errexit
set -o nounset

# enabling POSIX-compliant behavior for GNU programs
export POSIXLY_CORRECT=yes POSIX_ME_HARDER=yes


if [ "${0#/}" = "$0" ]; then
	argv0="$0"
else
	argv0="$(basename -- "$0" && printf x)"
	argv0="${argv0%"$(printf '\nx')"}"
fi
readonly argv0

#region checking SHELL environment variable

if [ -z "${SHELL-}" ]; then
	printf '%s: SHELL environment must not unset or empty\n' "$argv0" >&2
	exit 48
fi

if [ "${SHELL#"/"}" = "$SHELL" ]; then
	printf '%s: %s: SHELL environment variable must be an absolute pathname\n' "$argv0" "$SHELL" >&2
	exit 49
fi

#endregion

#region args

if [ $# -gt 0 ]; then
	printf '%s: too many arguments: %i\n' "$argv0" $# >&2
	exit 4
fi

#endregion

#region setting up variables

root_dir_pathname="$(dirname -- "$0" && printf x)"
root_dir_pathname="${root_dir_pathname%"$(printf '\nx')"}"
readonly root_dir_pathname

test_dir_pathname="$root_dir_pathname/test.d"
readonly test_dir_pathname

test_home_dir_pathname="$test_dir_pathname/root/${HOME#"/"}"
readonly test_home_dir_pathname

new_HOME_value="$test_home_dir_pathname"

if [ "${new_HOME_value#"/"}" = "$new_HOME_value" ]; then
	cwd="$(pwd -L && printf x)"
	cwd="${cwd%"$(printf '\nx')"}"

	new_HOME_value="$cwd/$new_HOME_value"

	unset -v cwd
fi

new_HOME_value="$(printf '%s' "$new_HOME_value" | sed -e s%'/./'%'/'%g)"

readonly new_HOME_value

#endregion

rm -rf -- "$test_dir_pathname"

"$root_dir_pathname/manage" install "$test_dir_pathname/root"
printf '*\n' > "$test_dir_pathname/.gitignore"

cd "$test_home_dir_pathname"

printf '\nA new shell instance has been started with an (almost) clean environment.\n' >&2

export PATH='/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/games:/usr/games'
export HOME="$new_HOME_value"
unset -v XDG_DATA_HOME
unset -v XDG_CONFIG_HOME
unset -v XDG_STATE_HOME
unset -v XDG_CACHE_HOME

unset -v POSIX_ME_HARDER POSIXLY_CORRECT

exec "$SHELL"