feat: api to bulk update legacy library references (#37789)

Adds API to fetch all legacy library content blocks that are ready to be updated to use library v2 and convert to item banks.
Also adds API to update all the references via a user celery task and to fetch its status.

cms/djangoapps/contentstore/api/tests/test_validation.py

@@ -1,23 +1,26 @@
 """
 Tests for the course import API views
 """
-
-import factory
 from datetime import datetime
-from django.conf import settings
+from unittest.mock import MagicMock, patch
+from uuid import uuid4
 
 import ddt
+import factory
+from django.conf import settings
+from django.contrib.auth import get_user_model
 from django.test.utils import override_settings
 from django.urls import reverse
 from rest_framework import status
 from rest_framework.test import APITestCase
-from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase
-from xmodule.modulestore.tests.factories import CourseFactory, BlockFactory
 
 from common.djangoapps.course_modes.models import CourseMode
 from common.djangoapps.course_modes.tests.factories import CourseModeFactory
-from common.djangoapps.student.tests.factories import StaffFactory
-from common.djangoapps.student.tests.factories import UserFactory
+from common.djangoapps.student.tests.factories import StaffFactory, UserFactory
+from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase
+from xmodule.modulestore.tests.factories import BlockFactory, CourseFactory
+
+User = get_user_model()
 
 
 @ddt.ddt
@@ -143,3 +146,129 @@ class CourseValidationViewTest(SharedModuleStoreTestCase, APITestCase):
                 'is_self_paced': True,
             }
             self.assertDictEqual(resp.data, expected_data)
+
+
+class TestMigrationViewSetCreate(SharedModuleStoreTestCase, APITestCase):
+    """
+    Test the MigrationViewSet.create() endpoint.
+
+    Focus: validation, return codes, serialization/deserialization.
+    """
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+
+        cls.course = CourseFactory.create(
+            display_name='test course',
+            run="Testing_course",
+            proctoring_provider='test_proctoring_provider',
+            proctoring_escalation_email='test@example.com',
+        )
+        cls.course_key = cls.course.id
+
+        cls.password = 'test'
+        cls.student = UserFactory(username='dummy', password=cls.password)
+        cls.staff = StaffFactory(course_key=cls.course.id, password=cls.password)
+
+        cls.initialize_course(cls.course)
+
+    @classmethod
+    def initialize_course(cls, course):
+        """
+        Sets up test course structure.
+        """
+        section = BlockFactory.create(
+            parent_location=course.location,
+            category="chapter",
+        )
+        subsection = BlockFactory.create(
+            parent_location=section.location,
+            category="sequential",
+        )
+        unit = BlockFactory.create(
+            parent_location=subsection.location,
+            category="vertical",
+        )
+        cls.block1 = BlockFactory.create(
+            parent_location=unit.location,
+            category="library_content",
+        )
+        cls.block2 = BlockFactory.create(
+            parent_location=unit.location,
+            category="library_content",
+        )
+
+    @patch('cms.djangoapps.contentstore.api.views.utils.has_course_author_access')
+    @patch('cms.djangoapps.contentstore.api.views.course_validation.UserTaskStatus')
+    @patch('xmodule.library_content_block.LegacyLibraryContentBlock.is_ready_to_migrate_to_v2')
+    def test_create_update_reference_success(self, mock_block, mock_user_task_status, mock_auth):
+        """
+        Test successful migration creation with minimal required fields.
+
+        Validates:
+        - 201 status code is returned
+        - Response contains expected serialized fields
+        - Request data is properly deserialized
+        - Permission checks are performed for both source and target
+        """
+        mock_auth.return_value = True
+
+        mock_task_status = MagicMock(autospec=True)
+        mock_task_status.uuid = uuid4()
+        mock_task_status.state = 'Pending'
+        mock_task_status.state_text = 'Pending'
+        mock_task_status.completed_steps = 0
+        mock_task_status.total_steps = 10
+        mock_task_status.attempts = 1
+        mock_task_status.created = '2025-01-01T00:00:00Z'
+        mock_task_status.modified = '2025-01-01T00:00:00Z'
+        mock_task_status.artifacts = []
+        mock_task_status.migrations.all.return_value = []
+
+        mock_user_task_status.objects.get.return_value = mock_task_status
+
+        mock_block.return_value = True
+
+        self.client.login(username=self.staff.username, password=self.password)
+        response = self.client.post(
+            f'/api/courses/v1/migrate_legacy_content_blocks/{self.course_key}/',
+        )
+
+        assert response.status_code == status.HTTP_201_CREATED
+
+        assert 'uuid' in response.data
+        assert 'state' in response.data
+        assert 'state_text' in response.data
+        assert 'completed_steps' in response.data
+        assert 'total_steps' in response.data
+
+        mock_auth.assert_called_once()
+
+    @patch('cms.djangoapps.contentstore.api.views.utils.has_course_author_access')
+    @patch('xmodule.library_content_block.LegacyLibraryContentBlock.is_ready_to_migrate_to_v2')
+    def test_list_ready_to_update_reference_success(self, mock_block, mock_auth):
+        """
+        Test successful migration creation with minimal required fields.
+
+        Validates:
+        - 201 status code is returned
+        - Response contains expected serialized fields
+        - Request data is properly deserialized
+        - Permission checks are performed for both source and target
+        """
+        mock_auth.return_value = True
+        mock_block.return_value = True
+
+        self.client.login(username=self.staff.username, password=self.password)
+        response = self.client.get(
+            f'/api/courses/v1/migrate_legacy_content_blocks/{self.course_key}/',
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        self.assertListEqual(data, [
+            {'usage_key': str(self.block1.location)},
+            {'usage_key': str(self.block2.location)},
+        ])
+        mock_auth.assert_called_once()