tiny-cloud: Print usage on invalid option and add test

Add test that verifies invalid option and `tiny-cloud --help`

sbin/tiny-cloud

@@ -21,8 +21,8 @@ bootstrap_incomplete() {
     rm -f "$TINY_CLOUD_VAR/.bootstrap-complete"
 }
 
-args=$(getopt -o hsb: --long help,setup,bootstrap: -n ${0##*/} -- "$@")
-if [ $? -ne 0 ] || [ $# -eq 0 ]; then
+args=$(getopt -o hsb: --long help,setup,bootstrap: -n ${0##*/} -- "$@") || {  usage >&2; exit 1; }
+if [ $# -eq 0 ]; then
     usage >&2
     exit 1
 fi

tests/tiny-cloud.test

@@ -0,0 +1,19 @@
+#!/usr/bin/env atf-sh
+
+. $(atf_get_srcdir)/test_env.sh
+
+export PREFIX="$srcdir"
+export MOCK=echo
+
+init_tests \
+	tiny_cloud_help
+
+tiny_cloud_help_body() {
+	CLOUD=nocloud atf_check -s not-exit:0 \
+		-e match:"Usage" \
+		tiny-cloud --invalid
+
+	CLOUD=nocloud atf_check -s exit:0 \
+		-o match:"Usage" \
+		tiny-cloud --help
+}