Implement internal mail skill MVP

internal/smtp/message_test.go

@@ -0,0 +1,90 @@
+package smtp
+
+import (
+	stdsmtp "net/smtp"
+	"strings"
+	"testing"
+
+	"internal-mail-skill/internal/config"
+)
+
+func TestBuildMessageOmitsBccHeaderButKeepsRecipients(t *testing.T) {
+	req := SendRequest{
+		FromAddress: "agent@example.com",
+		FromName:    "Agent",
+		To:          []string{"to@example.com"},
+		Cc:          []string{"cc@example.com"},
+		Bcc:         []string{"hidden@example.com"},
+		Subject:     "Hello",
+		Body:        "Body",
+	}
+
+	msg, recipients, err := BuildMessage(req)
+	if err != nil {
+		t.Fatalf("BuildMessage() error = %v", err)
+	}
+	raw := string(msg)
+	if strings.Contains(raw, "Bcc:") || strings.Contains(raw, "hidden@example.com") {
+		t.Fatalf("raw message leaked Bcc: %s", raw)
+	}
+	if len(recipients) != 3 {
+		t.Fatalf("recipients = %#v", recipients)
+	}
+	if recipients[2] != "hidden@example.com" {
+		t.Fatalf("Bcc missing from envelope recipients: %#v", recipients)
+	}
+}
+
+func TestAuthForConfigRequiresExplicitOptInForCleartextAuth(t *testing.T) {
+	cfg := config.SMTPConfig{
+		Host:         "smtp.example.local",
+		Username:     "user",
+		Password:     "secret",
+		AuthRequired: true,
+	}
+
+	if _, err := authForConfig(cfg); err == nil {
+		t.Fatal("authForConfig() error = nil, want cleartext auth rejection")
+	}
+
+	cfg.AllowInsecureAuth = true
+	auth, err := authForConfig(cfg)
+	if err != nil {
+		t.Fatalf("authForConfig() with opt-in error = %v", err)
+	}
+	proto, _, err := auth.Start(&stdsmtp.ServerInfo{Name: cfg.Host, TLS: false})
+	if err != nil {
+		t.Fatalf("insecure auth Start() error = %v", err)
+	}
+	if proto != "PLAIN" {
+		t.Fatalf("proto = %q, want PLAIN", proto)
+	}
+
+	cfg.AllowInsecureAuth = false
+	cfg.UseSTARTTLS = true
+	auth, err = authForConfig(cfg)
+	if err != nil {
+		t.Fatalf("authForConfig() over STARTTLS error = %v", err)
+	}
+	if _, _, err := auth.Start(&stdsmtp.ServerInfo{Name: cfg.Host, TLS: true}); err != nil {
+		t.Fatalf("TLS auth Start() error = %v", err)
+	}
+}
+
+func TestAuthForConfigAllowsImplicitTLSAuth(t *testing.T) {
+	cfg := config.SMTPConfig{
+		Host:         "smtp.example.local",
+		Username:     "user",
+		Password:     "secret",
+		AuthRequired: true,
+		UseTLS:       true,
+	}
+
+	auth, err := authForConfig(cfg)
+	if err != nil {
+		t.Fatalf("authForConfig() error = %v", err)
+	}
+	if _, _, err := auth.Start(&stdsmtp.ServerInfo{Name: cfg.Host, TLS: false}); err != nil {
+		t.Fatalf("implicit TLS auth Start() error = %v", err)
+	}
+}