[PATCH 4/4] Add test for using Git at root of file system

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

This kind of test requires a throw-away root filesystem so that it can
play on. If you have such a system, go ahead, "chmod 777 /" and run
this test manually ("make test" with root permission won't work).

If you don't but have Linux, static linked busybox, rsync and root
permission, then run "t/t1509/prepare-chroot.sh /tmp/test". You will be
instructed to create /dev/null and given a command to chroot into.
Within chroot, you will be placed at directory "t" of Git source code
Feel free to burn your chroot.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 May have problem committing. Anyway I don't need commit now.

 t/t1509-root-worktree.sh  |  244 +++++++++++++++++++++++++++++++++++++++++++++
 t/t1509/excludes          |   14 +++
 t/t1509/prepare-chroot.sh |   38 +++++++
 3 files changed, 296 insertions(+), 0 deletions(-)
 create mode 100755 t/t1509-root-worktree.sh
 create mode 100644 t/t1509/excludes
 create mode 100755 t/t1509/prepare-chroot.sh

diff --git a/t/t1509-root-worktree.sh b/t/t1509-root-worktree.sh
new file mode 100755
index 0000000..ae01b6d
--- /dev/null
+++ b/t/t1509-root-worktree.sh
@@ -0,0 +1,244 @@
+#!/bin/sh
+
+test_description='Test Git when git repository is located at root
+
+This test requires write access in root. Do not bother if you do not
+have a throwaway chroot or VM.
+
+Script t1509/prepare-chroot.sh may help you setup chroot, then you
+can chroot in and execute this test from there.
+'
+
+. ./test-lib.sh
+
+test_cmp_val() {
+	echo "$1" > expected
+	echo "$2" > result
+	test_cmp expected result
+}
+
+test_vars() {
+	test_expect_success "$1: gitdir" '
+		test_cmp_val "'"$2"'" "$(git rev-parse --git-dir)"
+	'
+
+	test_expect_success "$1: worktree" '
+		test_cmp_val "'"$3"'" "$(git rev-parse --show-toplevel)"
+	'
+
+	test_expect_success "$1: prefix" '
+		test_cmp_val "'"$4"'" "$(git rev-parse --show-prefix)"
+	'
+}
+
+test_foobar_root() {
+	test_expect_success 'add relative' '
+		test -z "$(cd / && git ls-files)" &&
+		git add foo/foome &&
+		git add foo/bar/barme &&
+		git add me &&
+		( cd / && git ls-files --stage ) > result &&
+		test_cmp /ls.expected result &&
+		rm "$(git rev-parse --git-dir)/index"
+	'
+
+	test_expect_success 'add absolute' '
+		test -z "$(cd / && git ls-files)" &&
+		git add /foo/foome &&
+		git add /foo/bar/barme &&
+		git add /me &&
+		( cd / && git ls-files --stage ) > result &&
+		test_cmp /ls.expected result &&
+		rm "$(git rev-parse --git-dir)/index"
+	'
+
+}
+
+test_foobar_foo() {
+	test_expect_success 'add relative' '
+		test -z "$(cd / && git ls-files)" &&
+		git add foome &&
+		git add bar/barme &&
+		git add ../me &&
+		( cd / && git ls-files --stage ) > result &&
+		test_cmp /ls.expected result &&
+		rm "$(git rev-parse --git-dir)/index"
+	'
+
+	test_expect_success 'add absolute' '
+		test -z "$(cd / && git ls-files)" &&
+		git add /foo/foome &&
+		git add /foo/bar/barme &&
+		git add /me &&
+		( cd / && git ls-files --stage ) > result &&
+		test_cmp /ls.expected result &&
+		rm "$(git rev-parse --git-dir)/index"
+	'
+}
+
+test_foobar_foobar() {
+	test_expect_success 'add relative' '
+		test -z "$(cd / && git ls-files)" &&
+		git add ../foome &&
+		git add barme &&
+		git add ../../me &&
+		( cd / && git ls-files --stage ) > result &&
+		test_cmp /ls.expected result &&
+		rm "$(git rev-parse --git-dir)/index"
+	'
+
+	test_expect_success 'add absolute' '
+		test -z "$(cd / && git ls-files)" &&
+		git add /foo/foome &&
+		git add /foo/bar/barme &&
+		git add /me &&
+		( cd / && git ls-files --stage ) > result &&
+		test_cmp /ls.expected result &&
+		rm "$(git rev-parse --git-dir)/index"
+	'
+}
+
+if ! test_have_prereq POSIXPERM || ! [ -w / ]; then
+	say "Dangerous test skipped. Read this test if you want to execute it"
+	test_done
+fi
+
+if [ "$IKNOWWHATIAMDOING" != "YES" ]; then
+	say "You must set env var IKNOWWHATIAMDOING=YES in order to run this test"
+	test_done
+fi
+
+ONE_SHA1=d00491fd7e5bb6fa28c517a0bb32b8b506539d4d
+
+test_expect_success 'setup' '
+	rm -rf /foo
+	mkdir /foo &&
+	mkdir /foo/bar &&
+	echo 1 > /foo/foome &&
+	echo 1 > /foo/bar/barme &&
+	echo 1 > /me
+'
+
+say "GIT_DIR absolute, GIT_WORK_TREE set"
+
+test_expect_success 'go to /' 'cd /'
+
+cat >ls.expected <<EOF
+100644 $ONE_SHA1 0	foo/bar/barme
+100644 $ONE_SHA1 0	foo/foome
+100644 $ONE_SHA1 0	me
+EOF
+
+export GIT_DIR="$TRASH_DIRECTORY/.git"
+export GIT_WORK_TREE=/
+
+test_vars 'abs gitdir, root' "$GIT_DIR" "/" ""
+test_foobar_root
+
+test_expect_success 'go to /foo' 'cd /foo'
+
+test_vars 'abs gitdir, foo' "$GIT_DIR" "/" "foo/"
+test_foobar_foo
+
+test_expect_success 'go to /foo/bar' 'cd /foo/bar'
+
+test_vars 'abs gitdir, foo/bar' "$GIT_DIR" "/" "foo/bar/"
+test_foobar_foobar
+
+say "GIT_DIR relative, GIT_WORK_TREE set"
+
+test_expect_success 'go to /' 'cd /'
+
+export GIT_DIR="$(echo $TRASH_DIRECTORY|sed 's,^/,,')/.git"
+export GIT_WORK_TREE=/
+
+test_vars 'rel gitdir, root' "$GIT_DIR" "/" ""
+test_foobar_root
+
+test_expect_success 'go to /foo' 'cd /foo'
+
+export GIT_DIR="../$TRASH_DIRECTORY/.git"
+export GIT_WORK_TREE=/
+
+test_vars 'rel gitdir, foo' "$TRASH_DIRECTORY/.git" "/" "foo/"
+test_foobar_foo
+
+test_expect_success 'go to /foo/bar' 'cd /foo/bar'
+
+export GIT_DIR="../../$TRASH_DIRECTORY/.git"
+export GIT_WORK_TREE=/
+
+test_vars 'rel gitdir, foo/bar' "$TRASH_DIRECTORY/.git" "/" "foo/bar/"
+test_foobar_foobar
+
+say "GIT_DIR relative, GIT_WORK_TREE relative"
+
+test_expect_success 'go to /' 'cd /'
+
+export GIT_DIR="$(echo $TRASH_DIRECTORY|sed 's,^/,,')/.git"
+export GIT_WORK_TREE=.
+
+test_vars 'rel gitdir, root' "$GIT_DIR" "/" ""
+test_foobar_root
+
+test_expect_success 'go to /' 'cd /foo'
+
+export GIT_DIR="../$TRASH_DIRECTORY/.git"
+export GIT_WORK_TREE=..
+
+test_vars 'rel gitdir, foo' "$TRASH_DIRECTORY/.git" "/" "foo/"
+test_foobar_foo
+
+test_expect_success 'go to /foo/bar' 'cd /foo/bar'
+
+export GIT_DIR="../../$TRASH_DIRECTORY/.git"
+export GIT_WORK_TREE=../..
+
+test_vars 'rel gitdir, foo/bar' "$TRASH_DIRECTORY/.git" "/" "foo/bar/"
+test_foobar_foobar
+
+say ".git at root"
+
+unset GIT_DIR
+unset GIT_WORK_TREE
+
+test_expect_success 'go to /' 'cd /'
+test_expect_success 'setup' '
+	rm -rf /.git
+	echo "Initialized empty Git repository in /.git/" > expected &&
+	git init > result &&
+	test_cmp expected result
+'
+
+test_vars 'auto gitdir, root' ".git" "/" ""
+test_foobar_root
+
+test_expect_success 'go to /foo' 'cd /foo'
+test_vars 'auto gitdir, foo' "/.git" "/" "foo/"
+test_foobar_foo
+
+test_expect_success 'go to /foo/bar' 'cd /foo/bar'
+test_vars 'auto gitdir, foo/bar' "/.git" "/" "foo/bar/"
+test_foobar_foobar
+
+test_expect_success 'cleanup' 'rm -rf /.git'
+
+say "auto bare gitdir"
+
+# DESTROYYYYY!!!!!
+test_expect_failure 'setup' '
+	rm -rf /refs /objects /info /hooks
+	rm /*
+	cd / &&
+	echo "Initialized empty Git repository in /" > expected &&
+	git init --bare > result &&
+	test_cmp expected result
+'
+
+test_vars 'auto gitdir, root' "." "" ""
+
+test_expect_success 'go to /foo' 'cd /foo'
+
+test_vars 'auto gitdir, root' "/" "" ""
+
+test_done
diff --git a/t/t1509/excludes b/t/t1509/excludes
new file mode 100644
index 0000000..d4d21d3
--- /dev/null
+++ b/t/t1509/excludes
@@ -0,0 +1,14 @@
+*.o
+*~
+*.bak
+*.c
+*.h
+.git
+contrib
+Documentation
+git-gui
+gitk-git
+gitweb
+t/t4013
+t/t5100
+t/t5515
diff --git a/t/t1509/prepare-chroot.sh b/t/t1509/prepare-chroot.sh
new file mode 100755
index 0000000..407f2d2
--- /dev/null
+++ b/t/t1509/prepare-chroot.sh
@@ -0,0 +1,38 @@
+#!/bin/sh
+
+die() {
+	echo >&2 "$@"
+	exit 1
+}
+
+xmkdir() {
+	while [ -n "$1" ]; do
+		[ -d "$1" ] || mkdir "$1" || die "Unable to mkdir $1"
+		shift
+	done
+}
+
+R="$1"
+
+[ -n "$R" ] || die "Usage: prepare-chroot.sh <root>"
+[ -x git ] || die "This script needs to be executed at git source code's top directory"
+[ -x /bin/busybox ] || die "You need busybox"
+
+xmkdir "$R" "$R/bin" "$R/etc" "$R/lib" "$R/dev"
+[ -c "$R/dev/null" ] || die "/dev/null is missing. Do mknod $R/dev/null c 1 3 && chmod 666 $R/dev/null"
+echo "root:x:0:0:root:/:/bin/sh" > "$R/etc/passwd"
+echo "$(id -nu):x:$(id -u):$(id -g)::$(pwd)/t:/bin/sh" >> "$R/etc/passwd"
+echo "root::0:root" > "$R/etc/group"
+echo "$(id -ng)::$(id -g):$(id -nu)" >> "$R/etc/group"
+
+[ -x "$R/bin/busybox" ] || cp /bin/busybox "$R/bin/busybox"
+[ -x "$R/bin/sh" ] || ln -s /bin/busybox "$R/bin/sh"
+[ -x "$R/bin/su" ] || ln -s /bin/busybox "$R/bin/su"
+
+mkdir -p "$R$(pwd)"
+rsync --exclude-from t/t1509/excludes -Ha . "$R$(pwd)"
+ldd git | grep '=> /' | sed 's,.* => *\([^ ]*\) .*,\1,' | while read i; do
+	mkdir -p "$R$(dirname $i)"
+	cp "$i" "$R/$i"
+done
+echo "Execute this in root: 'chroot $R /bin/su - $(id -nu)'"
-- 
1.7.0.rc2.182.g3adef