Unit test speed improvements (#4463)

* Unit test speed improvements

- Move from insantiating data in setUp to setUpTestData

* Update UserMixin class for API testing

* Bunch of test updates

* Further test updates

* Test fixes

* Add allowances for exchange rate server not responding

* Fixes for group role test

InvenTree/build/test_api.py

@@ -731,38 +731,42 @@ class BuildOverallocationTest(BuildAPITest):
     Using same Build ID=1 as allocation test above.
     """
 
-    def setUp(self):
+    @classmethod
+    def setUpTestData(cls):
         """Basic operation as part of test suite setup"""
-        super().setUp()
+        super().setUpTestData()
 
-        self.assignRole('build.add')
-        self.assignRole('build.change')
+        cls.assignRole('build.add')
+        cls.assignRole('build.change')
 
-        self.build = Build.objects.get(pk=1)
-        self.url = reverse('api-build-finish', kwargs={'pk': self.build.pk})
+        cls.build = Build.objects.get(pk=1)
+        cls.url = reverse('api-build-finish', kwargs={'pk': cls.build.pk})
 
         StockItem.objects.create(part=Part.objects.get(pk=50), quantity=30)
 
         # Keep some state for use in later assertions, and then overallocate
-        self.state = {}
-        self.allocation = {}
-        for i, bi in enumerate(self.build.part.bom_items.all()):
-            rq = self.build.required_quantity(bi, None) + i + 1
+        cls.state = {}
+        cls.allocation = {}
+
+        for i, bi in enumerate(cls.build.part.bom_items.all()):
+            rq = cls.build.required_quantity(bi, None) + i + 1
             si = StockItem.objects.filter(part=bi.sub_part, quantity__gte=rq).first()
 
-            self.state[bi.sub_part] = (si, si.quantity, rq)
+            cls.state[bi.sub_part] = (si, si.quantity, rq)
             BuildItem.objects.create(
-                build=self.build,
+                build=cls.build,
                 stock_item=si,
                 quantity=rq,
             )
 
         # create and complete outputs
-        self.build.create_build_output(self.build.quantity)
-        outputs = self.build.build_outputs.all()
-        self.build.complete_build_output(outputs[0], self.user)
+        cls.build.create_build_output(cls.build.quantity)
+        outputs = cls.build.build_outputs.all()
+        cls.build.complete_build_output(outputs[0], cls.user)
+
+    def test_setup(self):
+        """Validate expected state after set-up."""
 
-        # Validate expected state after set-up.
         self.assertEqual(self.build.incomplete_outputs.count(), 0)
         self.assertEqual(self.build.complete_outputs.count(), 1)
         self.assertEqual(self.build.completed, self.build.quantity)