Add subcommand init for checks and installs helmfile deps (#389)

* Add subcommand init for checks and installs helmfile deps

Signed-off-by: xiaomudk <xiaomudk@gmail.com>

test/e2e/helmfile-init/init_linux.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+# vim: set tabstop=4 shiftwidth=4
+
+set -e
+set -o pipefail
+
+# IMPORTS -----------------------------------------------------------------------------------------------------------
+
+# determine working directory to use to relative paths irrespective of starting directory
+dir="${BASH_SOURCE%/*}"
+if [[ ! -d "${dir}" ]]; then dir="${PWD}"; fi
+
+. "${dir}/../../integration/lib/output.sh"
+
+helmfile="./helmfile"
+helm_dir="${PWD}/${dir}/.helm"
+helm=`which helm`
+export HELM_DATA_HOME="${helm_dir}/data"
+export HELM_HOME="${HELM_DATA_HOME}"
+export HELM_PLUGINS="${HELM_DATA_HOME}/plugins"
+export HELM_CONFIG_HOME="${helm_dir}/config"
+
+function cleanup() {
+    set +e
+    info "Deleting ${helm_dir}"
+    rm -rf ${helm_dir} # remove helm data so reinstalling plugins does not fail
+}
+
+function removehelm() {
+  [ -f $helm ] && rm -rf $helm
+}
+
+set -e
+trap cleanup EXIT
+
+removehelm
+
+expect <<EOF
+set timeout -1
+spawn ${helmfile} init
+expect {
+    "*y/n" {send "y\r";exp_continue}
+    eof
+}
+EOF
+
+helm plugin ls | grep diff || fail "helmfile init run fail"
+
+all_tests_passed