test: tests Go para funciones email SMTP

Tests para builders puros (build_html, build_text, with_attachment), template_render, smtp_connect y smtp_send con mock TCP server. Todos los tests pasan: 18 casos cubriendo pureza, inmutabilidad y envio SMTP. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-04-13 02:01:18 +02:00
parent ef3ae2aae9
commit 6019f2aafa
4 changed files with 443 additions and 0 deletions
@@ -0,0 +1,120 @@
+package infra
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+	"strings"
+	"testing"
+)
+
+// mockSMTPServer starts a minimal SMTP server on a random port that greets
+// and accepts any commands. Returns the listener address and a function to stop it.
+func mockSMTPServer(t *testing.T) (addr string, stop func()) {
+	t.Helper()
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("mock smtp listen: %v", err)
+	}
+	go func() {
+		for {
+			conn, err := ln.Accept()
+			if err != nil {
+				return
+			}
+			go handleMockSMTP(conn)
+		}
+	}()
+	return ln.Addr().String(), func() { ln.Close() }
+}
+
+// handleMockSMTP is a minimal SMTP session handler (no TLS, no auth required).
+func handleMockSMTP(conn net.Conn) {
+	defer conn.Close()
+	w := bufio.NewWriter(conn)
+	r := bufio.NewReader(conn)
+	fmt.Fprintf(w, "220 mock SMTP ready\r\n")
+	w.Flush()
+	for {
+		line, err := r.ReadString('\n')
+		if err != nil {
+			return
+		}
+		line = strings.TrimSpace(line)
+		upper := strings.ToUpper(line)
+		switch {
+		case strings.HasPrefix(upper, "EHLO"), strings.HasPrefix(upper, "HELO"):
+			fmt.Fprintf(w, "250 mock\r\n")
+		case strings.HasPrefix(upper, "MAIL FROM"):
+			fmt.Fprintf(w, "250 OK\r\n")
+		case strings.HasPrefix(upper, "RCPT TO"):
+			fmt.Fprintf(w, "250 OK\r\n")
+		case strings.HasPrefix(upper, "DATA"):
+			fmt.Fprintf(w, "354 End with .\r\n")
+			w.Flush()
+			// read until ".\r\n"
+			for {
+				dl, derr := r.ReadString('\n')
+				if derr != nil {
+					return
+				}
+				if strings.TrimSpace(dl) == "." {
+					break
+				}
+			}
+			fmt.Fprintf(w, "250 OK\r\n")
+		case strings.HasPrefix(upper, "QUIT"):
+			fmt.Fprintf(w, "221 Bye\r\n")
+			w.Flush()
+			return
+		default:
+			fmt.Fprintf(w, "502 Command not recognized\r\n")
+		}
+		w.Flush()
+	}
+}
+
+func TestSMTPConnect(t *testing.T) {
+	t.Run("conecta sin cifrado a servidor mock", func(t *testing.T) {
+		addr, stop := mockSMTPServer(t)
+		defer stop()
+
+		host, portStr, _ := net.SplitHostPort(addr)
+		port := 0
+		fmt.Sscanf(portStr, "%d", &port)
+
+		cfg := SMTPConfig{
+			Host:    host,
+			Port:    port,
+			TLSMode: "", // no encryption
+		}
+		client, err := SMTPConnect(cfg)
+		if err != nil {
+			t.Fatalf("SMTPConnect: %v", err)
+		}
+		client.Quit()
+	})
+
+	t.Run("error si el servidor no existe", func(t *testing.T) {
+		// Use a port that is listening but immediately closes (RST) — we start
+		// and immediately close a listener so the port is known-closed.
+		ln2, err := net.Listen("tcp", "127.0.0.1:0")
+		if err != nil {
+			t.Fatalf("setup: %v", err)
+		}
+		h2, p2str, _ := net.SplitHostPort(ln2.Addr().String())
+		ln2.Close() // now nothing listens — connections get refused
+		p2 := 0
+		fmt.Sscanf(p2str, "%d", &p2)
+
+		cfg := SMTPConfig{
+			Host:    h2,
+			Port:    p2,
+			TLSMode: "",
+		}
+		_, connErr := SMTPConnect(cfg)
+		if connErr == nil {
+			t.Error("expected error for refused connection, got nil")
+		}
+	})
+}