tests: add initial bash completion tests

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t9902-completion.sh

@@ -0,0 +1,120 @@
+#!/bin/sh
+#
+# Copyright (c) 2012 Felipe Contreras
+#
+
+if test -n "$BASH" && test -z "$POSIXLY_CORRECT"; then
+	# we are in full-on bash mode
+	true
+elif type bash >/dev/null 2>&1; then
+	# execute in full-on bash mode
+	unset POSIXLY_CORRECT
+	exec bash "$0" "$@"
+else
+	echo '1..0 #SKIP skipping bash completion tests; bash not available'
+	exit 0
+fi
+
+test_description='test bash completion'
+
+. ./test-lib.sh
+
+complete ()
+{
+	# do nothing
+	return 0
+}
+
+. "$GIT_BUILD_DIR/contrib/completion/git-completion.bash"
+
+# We don't need this function to actually join words or do anything special.
+# Also, it's cleaner to avoid touching bash's internal completion variables.
+# So let's override it with a minimal version for testing purposes.
+_get_comp_words_by_ref ()
+{
+	while [ $# -gt 0 ]; do
+		case "$1" in
+		cur)
+			cur=${_words[_cword]}
+			;;
+		prev)
+			prev=${_words[_cword-1]}
+			;;
+		words)
+			words=("${_words[@]}")
+			;;
+		cword)
+			cword=$_cword
+			;;
+		esac
+		shift
+	done
+}
+
+print_comp ()
+{
+	local IFS=$'\n'
+	echo "${COMPREPLY[*]}" > out
+}
+
+run_completion ()
+{
+	local -a COMPREPLY _words
+	local _cword
+	_words=( $1 )
+	(( _cword = ${#_words[@]} - 1 ))
+	_git && print_comp
+}
+
+test_completion ()
+{
+	test $# -gt 1 && echo "$2" > expected
+	run_completion "$@" &&
+	test_cmp expected out
+}
+
+test_expect_success 'basic' '
+	run_completion "git \"\"" &&
+	# built-in
+	grep -q "^add \$" out &&
+	# script
+	grep -q "^filter-branch \$" out &&
+	# plumbing
+	! grep -q "^ls-files \$" out &&
+
+	run_completion "git f" &&
+	! grep -q -v "^f" out
+'
+
+test_expect_success 'double dash "git" itself' '
+	sed -e "s/Z$//" >expected <<-\EOF &&
+	--paginate Z
+	--no-pager Z
+	--git-dir=
+	--bare Z
+	--version Z
+	--exec-path Z
+	--html-path Z
+	--work-tree=
+	--namespace=
+	--help Z
+	EOF
+	test_completion "git --"
+'
+
+test_expect_success 'double dash "git checkout"' '
+	sed -e "s/Z$//" >expected <<-\EOF &&
+	--quiet Z
+	--ours Z
+	--theirs Z
+	--track Z
+	--no-track Z
+	--merge Z
+	--conflict=
+	--orphan Z
+	--patch Z
+	EOF
+	test_completion "git checkout --"
+'
+
+test_done