test(backend): add comprehensive tests for OAuth and agent endpoints

- Added tests for OAuth provider admin and consent endpoints covering edge cases.
- Extended agent-related tests to handle incorrect project associations and lifecycle state transitions.
- Introduced tests for sprint status transitions and validation checks.
- Improved multiline formatting consistency across all test functions.

backend/tests/crud/syndarix/test_sprint.py

@@ -9,7 +9,7 @@ import pytest
 import pytest_asyncio
 from sqlalchemy.exc import IntegrityError, OperationalError
 
-from app.crud.syndarix.sprint import CRUDSprint, sprint
+from app.crud.syndarix.sprint import sprint
 from app.models.syndarix import Issue, Project, Sprint
 from app.models.syndarix.enums import (
     IssueStatus,
@@ -174,7 +174,7 @@ class TestSprintGetByProject:
         self, db_session, test_project, test_sprint
     ):
         """Test getting sprints with status filter."""
-        sprints, total = await sprint.get_by_project(
+        sprints, _total = await sprint.get_by_project(
             db_session,
             project_id=test_project.id,
             status=SprintStatus.PLANNED,
@@ -478,7 +478,7 @@ class TestSprintWithIssueCounts:
         db_session.add_all([issue1, issue2])
         await db_session.commit()
 
-        results, total = await sprint.get_sprints_with_issue_counts(
+        results, _total = await sprint.get_sprints_with_issue_counts(
             db_session, project_id=test_project.id
         )
         assert len(results) == 1