Test migration outcomes

Author: Andy Babic

tests/test_migration_outcomes.py

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+import copy
+
+from unittest import mock
+
+from django.test import TestCase
+from testapp.constants import COMPLEX_MODIFIED_BODY_VALUE, COMPLEX_ORIGINAL_BODY_VALUE
+from testapp.models import TestPage, TestSnippet
+
+
+# StreamField will have generated random 'id' values for blocks in some cases,
+# so the following constants allow us to successfully compare raw field values
+# against hardcoded ones, without caring about the 'id' value
+
+COMPARABLE_MODIFIED_BODY_VALUE = copy.deepcopy(COMPLEX_MODIFIED_BODY_VALUE)
+for item in COMPARABLE_MODIFIED_BODY_VALUE:
+    item["id"] = mock.ANY
+
+
+COMPARABLE_ORIGINAL_BODY_VALUE = copy.deepcopy(COMPLEX_ORIGINAL_BODY_VALUE)
+for item in COMPARABLE_ORIGINAL_BODY_VALUE:
+    item["id"] = mock.ANY
+
+
+class TestMigrationOutcomes(TestCase):
+    @classmethod
+    def setUpTestData(cls):
+        for i, page in enumerate(TestPage.objects.all().order_by("id"), start=1):
+            setattr(cls, f"page_{i}", page)
+        for i, snippet in enumerate(TestSnippet.objects.all().order_by("id"), start=1):
+            setattr(cls, f"snippet_{i}", snippet)
+
+    def test_original_pages_and_snippets_have_retained_their_original_body_values(self):
+        """
+        Test the objects created in `0002_create_test_objects` and DID NOT have their `body` value
+        updated in later migrations have retained their original values after:
+
+        - Swapping the native StreamField for a custom one in `0003_swap_native_streamfield_for_mlstreamfield`
+        - Updating their title in `0007_modify_title_values` and resaving
+        - Updating their title in `0008_modify_title_values_with_bulk_update` via a bulk update
+        """
+        self.assertEqual(
+            self.page_1.body.raw_data,
+            COMPARABLE_ORIGINAL_BODY_VALUE,
+        )
+        self.assertEqual(
+            self.snippet_1.body.raw_data,
+            COMPARABLE_ORIGINAL_BODY_VALUE,
+        )
+
+    def test_modified_original_pages_and_snippets_have_retained_their_modified_body_values(self):
+        """
+        Test that the objects created in `0002_create_test_objects` and had their `body` value
+        later modified in `0004_modify_body_values` have retained that updated body value after:
+
+        - Updating their `title` value in `0007_modify_title_values` and resaving
+        """
+        self.assertEqual(
+            self.page_2.body.raw_data,
+            COMPARABLE_MODIFIED_BODY_VALUE,
+        )
+        self.assertEqual(
+            self.snippet_2.body.raw_data,
+            COMPARABLE_MODIFIED_BODY_VALUE,
+        )
+
+    def test_newer_pages_and_snippets_have_retained_their_original_body_values(self):
+        """
+        Test that the objects created in `0005_create_more_test_objects` and DID NOT have their body
+        value updated in later migrations have retained their original values after:
+
+        - Updating their `title` value in `0007_modify_title_values` and resaving
+        - Updating their `title` value again in `0008_modify_title_values_with_bulk_update` via a bulk update
+        """
+        self.assertEqual(
+            self.page_3.body.raw_data,
+            COMPARABLE_ORIGINAL_BODY_VALUE,
+        )
+        self.assertEqual(
+            self.snippet_3.body.raw_data,
+            COMPARABLE_ORIGINAL_BODY_VALUE,
+        )
+
+    def test_modified_newer_pages_and_snippets_have_retained_their_modified_body_values(self):
+        """
+        Tests that the objects created in `0005_create_more_test_objects` and had their `body` value
+        later modified in `0006_modify_body_values_with_bulk_update` have retained that updated `body`
+        value after:
+
+        - Updating their `title` value in `0007_modify_title_values` and resaving
+        - Updating their `title` value again in `0008_modify_title_values_with_bulk_update` via a bulk update
+        """
+        self.assertEqual(
+            self.page_4.body.raw_data,
+            COMPARABLE_MODIFIED_BODY_VALUE,
+        )
+        self.assertEqual(
+            self.snippet_4.body.raw_data,
+            COMPARABLE_MODIFIED_BODY_VALUE,
+        )