[FIX] account_global_discount: Make tests resilient

- Depending on the installed set of modules, the company currency may
  be USD or EUR. If the second case, these tests will fail, so we make
  sure that the company currency is USD for our tests, doing the change
  by SQL, as there's a Python constraint that prevents it.

Not needed in v17 due to: odoo/odoo#107113.

account_global_discount/tests/test_global_discount.py

@@ -17,6 +17,16 @@ def setUpClass(cls, chart_template_ref=None):
         cls.env.ref("base_global_discount.group_global_discount").write(
             {"users": [(4, cls.env.user.id)]}
         )
+        cls.currency_eur = cls.env.ref("base.EUR")
+        cls.currency_usd = cls.env.ref("base.USD")
+        cls.currency_usd.active = True
+        # Make sure the currency of the company is USD, as this not always happens
+        # To be removed in V17: https://github.com/odoo/odoo/pull/107113
+        cls.company = cls.env.company
+        cls.env.cr.execute(
+            "UPDATE res_company SET currency_id = %s WHERE id = %s",
+            (cls.env.ref("base.USD").id, cls.company.id),
+        )
         cls.account = cls.env["account.account"].create(
             {
                 "name": "Test account",