import unittest

from app.features.story.backfill import backfill_image_into_markdown


class StoryBackfillTest(unittest.TestCase):
    def test_appends_image_at_end_with_prompt_brief_alt(self):
        md = "第一段\n\n第二段"
        out = backfill_image_into_markdown(md, "aid-1", "院子里的藤椅")
        self.assertTrue(out.endswith("](asset://aid-1)\n"))
        self.assertIn("第二段", out)
        self.assertLess(out.index("第二段"), out.index("!["))

    def test_empty_markdown_is_only_image_ref(self):
        out = backfill_image_into_markdown("", "x", "提示")
        self.assertEqual(out, "![提示](asset://x)")

    def test_escapes_bracket_in_alt(self):
        out = backfill_image_into_markdown("正文", "a", "说明]尾")
        self.assertIn(r"说明\]", out)