add automated test for quickstart

with tls with acme (with pebble, a small acme server for testing), and with
pregenerated keys/certs.

the two mox instances are configured on their own domain. we launch a separate
test container that connects to the first, submits a message for delivery to
the second. we check if the message is delivered with an imap connection and
the idle command.

quickstart_test.go

@@ -0,0 +1,145 @@
+//go:build quickstart
+
+// Run this using docker-compose.yml, see Makefile.
+
+package main
+
+import (
+	"bytes"
+	"crypto/tls"
+	"encoding/base64"
+	"fmt"
+	"os"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/mjl-/mox/imapclient"
+	"github.com/mjl-/mox/mlog"
+	"github.com/mjl-/mox/mox-"
+	"github.com/mjl-/mox/smtpclient"
+)
+
+var xlog = mlog.New("quickstart")
+
+func tcheck(t *testing.T, err error, msg string) {
+	t.Helper()
+	if err != nil {
+		t.Fatalf("%s: %s", msg, err)
+	}
+}
+
+func TestDeliver(t *testing.T) {
+	mlog.Logfmt = true
+
+	// smtpclient uses the hostname for outgoing connections.
+	var err error
+	mox.Conf.Static.HostnameDomain.ASCII, err = os.Hostname()
+	tcheck(t, err, "hostname")
+
+	// Deliver submits a message over submissions, and checks with imap idle if the
+	// message is received by the destination mail server.
+	deliver := func(desthost, mailfrom, password, rcptto, imaphost, imapuser, imappassword string) {
+		t.Helper()
+
+		// Connect to IMAP, execute IDLE command, which will return on deliver message.
+		// TLS certificates work because the container has the CA certificates configured.
+		imapconn, err := tls.Dial("tcp", imaphost+":993", nil)
+		tcheck(t, err, "dial imap")
+		defer imapconn.Close()
+
+		imaperr := make(chan error, 1)
+		go func() {
+			go func() {
+				x := recover()
+				if x == nil {
+					return
+				}
+				imaperr <- x.(error)
+			}()
+			xcheck := func(err error, format string) {
+				if err != nil {
+					panic(fmt.Errorf("%s: %w", format, err))
+				}
+			}
+
+			imapc, err := imapclient.New(imapconn, false)
+			xcheck(err, "new imapclient")
+
+			_, _, err = imapc.Login(imapuser, imappassword)
+			xcheck(err, "imap login")
+
+			_, _, err = imapc.Select("Inbox")
+			xcheck(err, "imap select inbox")
+
+			err = imapc.Commandf("", "idle")
+			xcheck(err, "write imap idle command")
+			_, _, _, err = imapc.ReadContinuation()
+			xcheck(err, "read imap continuation")
+
+			done := make(chan error)
+			go func() {
+				defer func() {
+					x := recover()
+					if x != nil {
+						done <- fmt.Errorf("%v", x)
+					}
+				}()
+				untagged, err := imapc.ReadUntagged()
+				if err != nil {
+					done <- err
+					return
+				}
+				if _, ok := untagged.(imapclient.UntaggedExists); !ok {
+					done <- fmt.Errorf("expected imapclient.UntaggedExists, got %#v", untagged)
+					return
+				}
+				done <- nil
+			}()
+
+			period := 30 * time.Second
+			timer := time.NewTimer(period)
+			defer timer.Stop()
+			select {
+			case err = <-done:
+			case <-timer.C:
+				err = fmt.Errorf("nothing within %v", period)
+			}
+			xcheck(err, "waiting for imap untagged repsonse to idle")
+			imaperr <- nil
+		}()
+
+		conn, err := tls.Dial("tcp", desthost+":465", nil)
+		tcheck(t, err, "dial submission")
+		defer conn.Close()
+
+		msg := fmt.Sprintf(`From: <%s>
+To: <%s>
+Subject: test message
+
+This is the message.
+`, mailfrom, rcptto)
+		msg = strings.ReplaceAll(msg, "\n", "\r\n")
+		auth := bytes.Join([][]byte{nil, []byte(mailfrom), []byte(password)}, []byte{0})
+		authLine := fmt.Sprintf("AUTH PLAIN %s", base64.StdEncoding.EncodeToString(auth))
+		c, err := smtpclient.New(mox.Context, xlog, conn, smtpclient.TLSSkip, desthost, authLine)
+		tcheck(t, err, "smtp hello")
+		err = c.Deliver(mox.Context, mailfrom, rcptto, int64(len(msg)), strings.NewReader(msg), false, false)
+		tcheck(t, err, "deliver with smtp")
+		err = c.Close()
+		tcheck(t, err, "close smtpclient")
+
+		err = <-imaperr
+		tcheck(t, err, "imap idle")
+	}
+
+	xlog.Print("submitting email to moxacmepebble, waiting for imap notification at moxmail2, takes time because first-time sender")
+	t0 := time.Now()
+	deliver("moxacmepebble.mox1.example", "moxtest1@mox1.example", "accountpass1234", "moxtest2@mox2.example", "moxmail2.mox2.example", "moxtest2@mox2.example", "accountpass4321")
+	xlog.Print("success", mlog.Field("duration", time.Since(t0)))
+
+	xlog.Print("submitting email to moxmail2, waiting for imap notification at moxacmepebble, takes time because first-time sender")
+	t0 = time.Now()
+	deliver("moxmail2.mox2.example", "moxtest2@mox2.example", "accountpass4321", "moxtest1@mox1.example", "moxacmepebble.mox1.example", "moxtest1@mox1.example", "accountpass1234")
+	xlog.Print("success", mlog.Field("duration", time.Since(t0)))
+}