[FIX] mass_mailing_sms: fix sms link placeholders tests

In no-demo tests, there is no link tracker, so
the expected length is not max+1 but 3.

Follow up of e5b88d3

Task-3502174

closes odoo#173303

Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>

addons/mass_mailing_sms/tests/test_mailing_internals.py

@@ -77,8 +77,10 @@ def test_mailing_get_sms_link_replacements_placeholders(self):
  })
  base_url = self.env['mailing.mailing'].get_base_url()
 
+ link_trackers = bool(self.env['link.tracker'].search([], limit=1)) # depends on demo
+
  expected = {
- 'link': f'{base_url}/r/xxxx/s/xxxxx',
+ 'link': f'{base_url}/r/xxx{"x" if link_trackers else ""}/s/xxxxx',
  'unsubscribe': f"\nSTOP SMS : {base_url}/sms/{'x' * len(str(mailing.id))}/{'x' * self.env['mailing.trace'].CODE_SIZE}",
  }
  self.assertDictEqual(mailing.get_sms_link_replacements_placeholders(), expected)