refactor(backend): remove network dep from test (#12624)

src/backend/InvenTree/InvenTree/tests.py

@@ -2,7 +2,6 @@
 
 import base64
 import os
-import time
 from datetime import datetime, timedelta
 from decimal import Decimal
 from io import BytesIO
@@ -22,6 +21,7 @@ from django.urls import reverse
 from django.utils import timezone
 
 import pint.errors
+import requests_mock
 from djmoney.contrib.exchange.exceptions import MissingRate
 from djmoney.contrib.exchange.models import Rate, convert_money
 from djmoney.money import Money
@@ -1171,8 +1171,26 @@ class TestVersionNumber(TestCase):
 class CurrencyTests(TestCase):
     """Unit tests for currency / exchange rate functionality."""
 
-    def test_rates(self):
+    RATES = {
+        'AUD': 1.5,
+        'CAD': 1.35,
+        'CNY': 7.2,
+        'EUR': 0.9,
+        'GBP': 0.8,
+        'JPY': 150.0,
+        'NZD': 1.65,
+        'USD': 1.0,
+    }
+
+    @requests_mock.Mocker()
+    def test_rates(self, requests_mocker):
         """Test exchange rate update."""
+        # Patch setting for remote url
+        response_rates = {code: self.RATES.get(code, 1.0) for code in currency_codes()}
+        requests_mocker.get(
+            'https://api.frankfurter.app/latest', json={'rates': response_rates}
+        )
+
         # Initially, there will not be any exchange rate information
         rates = Rate.objects.all()
 
@@ -1185,24 +1203,10 @@ class CurrencyTests(TestCase):
         with self.assertRaises(MissingRate):
             convert_money(Money(100, 'AUD'), 'USD')
 
-        update_successful = False
-
-        # Note: the update sometimes fails in CI, let's give it a few chances
-        for idx in range(10):
         InvenTree.tasks.update_exchange_rates()
 
         rates = Rate.objects.all()
-
-            if rates.count() == len(currency_codes()):
-                update_successful = True
-                break
-
-            else:  # pragma: no cover
-                print('Exchange rate update failed - retrying')
-                print(f'Expected {currency_codes()}, got {[a.currency for a in rates]}')
-                time.sleep(1 + idx)
-
-        self.assertTrue(update_successful)
+        self.assertEqual(rates.count(), len(currency_codes()))
 
         # Now that we have some exchange rate information, we can perform conversions