test: Add a new local end-to-end test

This patch introduces a new directory, test/, which contains a simple local
end-to-end test which runs a chasquid binary and uses msmtp to send an email,
which is delivered locally.

As it's the first one, it adds a bunch of common infrastructure to simplify
writing these kinds of tests.

More end-to-end tests will follow, and it's expected that the common
infrastructure will also change significantly to accomodate their needs.

test/util/lib.sh

@@ -0,0 +1,74 @@
+# Library to write the shell scripts in the tests.
+
+function init() {
+	if [ "$V" == "1" ]; then
+		set -v
+	fi
+
+	export TBASE="$(realpath `dirname ${0}`)"
+	cd ${TBASE}
+
+	export UTILDIR="$(realpath ${TBASE}/../util/)"
+
+	# Remove the directory where test-mda will deliver mail, so previous
+	# runs don't interfere with this one.
+	rm -rf .mail
+
+	# Set traps to kill our subprocesses when we exit (for any reason).
+	# https://stackoverflow.com/questions/360201/
+	trap "exit" INT TERM
+	trap "kill 0" EXIT
+}
+
+function generate_cert() {
+	go run ${UTILDIR}/generate_cert.go "$@"
+}
+
+function chasquid() {
+	# HOSTALIASES: so we "fake" hostnames.
+	# PATH: so chasquid can call test-mda without path issues.
+	HOSTALIASES=${TBASE}/hosts \
+	PATH=${UTILDIR}:${PATH} \
+		go run ${TBASE}/../../chasquid.go "$@"
+}
+
+function run_msmtp() {
+	# msmtp will check that the rc file is only user readable.
+	chmod 600 msmtprc
+
+	HOSTALIASES=${TBASE}/hosts \
+		msmtp -C msmtprc "$@"
+}
+
+function mail_diff() {
+	${UTILDIR}/mail_diff "$@"
+}
+
+function success() {
+	echo "SUCCESS"
+}
+
+# Wait until there's something listening on the given port.
+function wait_until_ready() {
+	PORT=$1
+
+	while ! nc -z localhost $PORT; do
+		sleep 0.1
+	done
+}
+
+# Wait for the given file to exist.
+function wait_for_file() {
+	while ! [ -e ${1} ]; do
+		sleep 0.1
+	done
+}
+
+# Generate certs for the given domain.
+function generate_certs_for() {
+	mkdir -p config/domains/${1}
+	(
+		cd config/domains/${1}
+		generate_cert -ca -duration=1h -host=${1}
+	)
+}