feat: Sprint 3 — test editing with versioning

Backend:
- migration 003: add parent_id to tests table
- PUT /api/tests/{id}: edit in place if no attempts, create new version otherwise
- GET /api/tests: show only latest versions (no successor)

Frontend:
- TestForm: extracted reusable form component
- TestCreate: refactored to use TestForm
- TestEdit: full edit mode with pre-populated form, version redirect on new version

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/api/tests.py

@@ -1,21 +1,25 @@
 from fastapi import APIRouter, Depends, HTTPException
-from sqlalchemy import select
+from sqlalchemy import delete, func, select
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import selectinload
 
 from app.database import get_db
+from app.models.attempt import TestAttempt
 from app.models.test import Answer, Question, Test
-from app.schemas.test import TestCreate, TestListItem, TestOut
+from app.schemas.test import TestCreate, TestListItem, TestOut, TestUpdateResponse
 
 router = APIRouter(prefix="/api/tests", tags=["tests"])
 
 
 @router.get("", response_model=list[TestListItem])
 async def list_tests(db: AsyncSession = Depends(get_db)):
+    # Показываем только последние версии: те, чей id не упоминается как parent_id
+    parent_ids_subq = select(Test.parent_id).where(Test.parent_id.is_not(None))
+
     result = await db.execute(
         select(Test)
         .options(selectinload(Test.questions))
-        .where(Test.is_active == True)
+        .where(Test.is_active == True, Test.id.not_in(parent_ids_subq))
         .order_by(Test.created_at.desc())
     )
     tests = result.scalars().all()
@@ -68,10 +72,90 @@ async def create_test(data: TestCreate, db: AsyncSession = Depends(get_db)):
 
     await db.commit()
 
-    # Перезагружаем с вложенными связями
     result = await db.execute(
         select(Test)
         .options(selectinload(Test.questions).selectinload(Question.answers))
         .where(Test.id == test.id)
     )
     return result.scalar_one()
+
+
+@router.put("/{test_id}", response_model=TestUpdateResponse)
+async def update_test(test_id: int, data: TestCreate, db: AsyncSession = Depends(get_db)):
+    result = await db.execute(
+        select(Test)
+        .where(Test.id == test_id, Test.is_active == True)
+    )
+    test = result.scalar_one_or_none()
+    if not test:
+        raise HTTPException(status_code=404, detail="Тест не найден")
+
+    # Проверяем, есть ли уже попытки прохождения
+    attempts_count = await db.scalar(
+        select(func.count()).select_from(TestAttempt).where(TestAttempt.test_id == test_id)
+    )
+
+    if attempts_count == 0:
+        # Редактируем на месте: обновляем поля, пересоздаём вопросы
+        test.title = data.title
+        test.description = data.description
+        test.passing_score = data.passing_score
+        test.time_limit = data.time_limit
+        test.allow_navigation_back = data.allow_navigation_back
+
+        await db.execute(delete(Question).where(Question.test_id == test_id))
+        await db.flush()
+
+        for order, q_data in enumerate(data.questions):
+            question = Question(test_id=test.id, text=q_data.text, order=order)
+            db.add(question)
+            await db.flush()
+            for a_data in q_data.answers:
+                db.add(Answer(
+                    question_id=question.id,
+                    text=a_data.text,
+                    is_correct=a_data.is_correct,
+                ))
+
+        await db.commit()
+
+        result = await db.execute(
+            select(Test)
+            .options(selectinload(Test.questions).selectinload(Question.answers))
+            .where(Test.id == test.id)
+        )
+        return {"test": result.scalar_one(), "is_new_version": False}
+
+    else:
+        # Есть попытки — создаём новую версию
+        new_test = Test(
+            title=data.title,
+            description=data.description,
+            passing_score=data.passing_score,
+            time_limit=data.time_limit,
+            allow_navigation_back=data.allow_navigation_back,
+            version=test.version + 1,
+            parent_id=test.id,
+        )
+        db.add(new_test)
+        await db.flush()
+
+        for order, q_data in enumerate(data.questions):
+            question = Question(test_id=new_test.id, text=q_data.text, order=order)
+            db.add(question)
+            await db.flush()
+            for a_data in q_data.answers:
+                db.add(Answer(
+                    question_id=question.id,
+                    text=a_data.text,
+                    is_correct=a_data.is_correct,
+                ))
+
+        await db.commit()
+
+        result = await db.execute(
+            select(Test)
+            .options(selectinload(Test.questions).selectinload(Question.answers))
+            .where(Test.id == new_test.id)
+        )
+        return {"test": result.scalar_one(), "is_new_version": True}