feat: support image inputs in assistant tests

backend/services/test_case_assets.py

@@ -0,0 +1,72 @@
+"""Validation and loading helpers for image fixtures in test definitions."""
+
+from __future__ import annotations
+
+import asyncio
+
+from db.models import TestAsset
+from services.test_assets import read_test_image
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+from test_schemas import TestCaseDefinition
+
+
+def image_asset_ids(definition: TestCaseDefinition) -> set[str]:
+    return {
+        turn.image.asset_id
+        for turn in definition.turns
+        if turn.image is not None
+    }
+
+
+async def canonicalize_test_assets(
+    session: AsyncSession,
+    definition: TestCaseDefinition,
+) -> None:
+    """Validate references and replace client metadata with authoritative values."""
+
+    asset_ids = image_asset_ids(definition)
+    if not asset_ids:
+        return
+    rows = (
+        await session.execute(select(TestAsset).where(TestAsset.id.in_(asset_ids)))
+    ).scalars().all()
+    by_id = {row.id: row for row in rows}
+    missing = sorted(asset_ids - by_id.keys())
+    if missing:
+        raise ValueError("测试图片不存在: " + "、".join(missing))
+
+    for turn in definition.turns:
+        if turn.image is None:
+            continue
+        row = by_id[turn.image.asset_id]
+        turn.image.filename = row.original_name
+        turn.image.width = row.width
+        turn.image.height = row.height
+        turn.image.size_bytes = row.size_bytes
+
+
+async def load_test_asset_bytes(
+    session: AsyncSession,
+    definition: TestCaseDefinition,
+) -> dict[str, bytes]:
+    """Load immutable image fixtures once before a transportless test attempt."""
+
+    asset_ids = image_asset_ids(definition)
+    if not asset_ids:
+        return {}
+    rows = (
+        await session.execute(select(TestAsset).where(TestAsset.id.in_(asset_ids)))
+    ).scalars().all()
+    by_id = {row.id: row for row in rows}
+    missing = sorted(asset_ids - by_id.keys())
+    if missing:
+        raise ValueError("测试图片不存在: " + "、".join(missing))
+
+    pairs = await asyncio.gather(
+        *(
+            asyncio.to_thread(read_test_image, row.storage_key)
+            for row in rows
+        )
+    )
+    return {row.id: data for row, data in zip(rows, pairs, strict=True)}