Impedisce combinazioni SMTP errate tra porta e crittografia.

Evita l'errore SSL wrong version number quando SSL/TLS è impostato sulla porta 587 invece che sulla 465.

Co-authored-by: Cursor <cursoragent@cursor.com>

test/models/mail_identity_test.rb

@@ -0,0 +1,52 @@
+require "test_helper"
+
+class MailIdentityTest < ActiveSupport::TestCase
+  test "smtp settings use starttls on port 587" do
+    identity = MailIdentity.new(
+      name: "Test",
+      from_name: "Test",
+      from_email: "hello@example.com",
+      smtp_host: "smtp.example.com",
+      smtp_port: 587,
+      encryption: "starttls",
+      smtp_authentication: "plain",
+      active: true
+    )
+    assert identity.valid?
+    settings = identity.smtp_settings
+    assert settings[:enable_starttls_auto]
+    assert_not settings[:ssl]
+  end
+
+  test "smtp settings use ssl on port 465" do
+    identity = MailIdentity.new(
+      name: "Test",
+      from_name: "Test",
+      from_email: "hello@example.com",
+      smtp_host: "smtps.example.com",
+      smtp_port: 465,
+      encryption: "tls",
+      smtp_authentication: "plain",
+      active: true
+    )
+    assert identity.valid?
+    settings = identity.smtp_settings
+    assert settings[:ssl]
+    assert_not settings[:enable_starttls_auto]
+  end
+
+  test "rejects ssl encryption on port 587" do
+    identity = MailIdentity.new(
+      name: "Test",
+      from_name: "Test",
+      from_email: "hello@example.com",
+      smtp_host: "smtps.example.com",
+      smtp_port: 587,
+      encryption: "tls",
+      smtp_authentication: "plain",
+      active: true
+    )
+    assert_not identity.valid?
+    assert_includes identity.errors[:smtp_port], "con SSL/TLS va usata la porta 465 (es. smtps.aruba.it)"
+  end
+end