[FIX] sale_expense,sale: fix tests that depend of the USD currency

The assertEqual compare arbitrary amounts related to the USD.
This leads to error when changing the currency of the base.main_company.

addons/sale/tests/test_product_id_change.py

@@ -24,6 +24,9 @@ class TestOnchangeProductId(TransactionCase):
         self.pricelist_model = self.env['product.pricelist']
 
     def test_onchange_product_id(self):
+        # Ensure the computation are done with the USD currency
+        base_company = self.env.ref('base.main_company')
+        base_company.currency_id = self.env.ref('base.USD')
 
         uom_id = self.product_uom_model.search([('name', '=', 'Unit(s)')])[0]
         pricelist = self.pricelist_model.search([('name', '=', 'Public Pricelist')])[0]

addons/sale/tests/test_sale_order.py

@@ -104,6 +104,10 @@ class TestSaleOrder(TestSale):
 
     def test_cost_invoicing(self):
         """ Test confirming a vendor invoice to reinvoice cost on the so """
+        # Ensure the computation are done with the USD currency
+        base_company = self.env.ref('base.main_company')
+        base_company.currency_id = self.env.ref('base.USD')
+
         serv_cost = self.env.ref('product.service_cost_01')
         prod_gap = self.env.ref('product.product_product_1')
         so = self.env['sale.order'].create({

addons/sale_expense/tests/test_sale_expense.py

@@ -7,6 +7,9 @@ from odoo.addons.sale.tests.test_sale_common import TestSale
 class TestSaleExpense(TestSale):
     def test_sale_expense(self):
         """ Test the behaviour of sales orders when managing expenses """
+        # Ensure the computation are done with the USD currency
+        base_company = self.env.ref('base.main_company')
+        base_company.currency_id = self.env.ref('base.USD')
         # create a so with a product invoiced on delivery
         prod = self.env.ref('product.product_product_1')
         so = self.env['sale.order'].create({