feat: add generation trace and partial-ready workflow status

backend/tests/test_story_status.py

@@ -0,0 +1,109 @@
+"""Tests for derived story generation statuses."""
+
+from types import SimpleNamespace
+
+from app.services.story_status import (
+    StoryAssetStatus,
+    StoryGenerationStatus,
+    resolve_story_generation_status,
+    sync_story_status,
+)
+
+
+def make_story(**overrides):
+    data = {
+        "story_text": "Once upon a time.",
+        "pages": None,
+        "cover_prompt": "A warm forest cover",
+        "image_url": None,
+        "generation_status": "narrative_ready",
+        "text_status": "ready",
+        "image_status": "not_requested",
+        "audio_status": "not_requested",
+        "last_error": None,
+    }
+    data.update(overrides)
+    return SimpleNamespace(**data)
+
+
+def test_text_story_without_assets_is_partial_ready():
+    story = make_story()
+
+    sync_story_status(story)
+
+    assert story.text_status == "ready"
+    assert story.generation_status == StoryGenerationStatus.PARTIAL_READY.value
+
+
+def test_text_story_with_all_assets_is_completed():
+    story = make_story(
+        image_url="https://example.com/cover.png",
+        image_status="ready",
+        audio_status="ready",
+    )
+
+    assert resolve_story_generation_status(story) == StoryGenerationStatus.COMPLETED
+
+
+def test_failed_asset_keeps_readable_story_degraded():
+    story = make_story(image_status="failed", last_error="cover failed")
+
+    sync_story_status(story)
+
+    assert story.text_status == "ready"
+    assert story.generation_status == StoryGenerationStatus.DEGRADED_COMPLETED.value
+    assert story.last_error == "cover failed"
+
+
+def test_storybook_missing_page_image_is_partial_ready():
+    story = make_story(
+        story_text=None,
+        pages=[
+            {
+                "page_number": 1,
+                "text": "Page one",
+                "image_prompt": "Page one image",
+                "image_url": "https://example.com/page-1.png",
+            },
+            {
+                "page_number": 2,
+                "text": "Page two",
+                "image_prompt": "Page two image",
+                "image_url": None,
+            },
+        ],
+        cover_prompt="Storybook cover",
+        image_url="https://example.com/cover.png",
+        image_status="not_requested",
+    )
+
+    assert resolve_story_generation_status(story) == StoryGenerationStatus.PARTIAL_READY
+
+
+def test_storybook_with_all_images_is_completed():
+    story = make_story(
+        story_text=None,
+        pages=[
+            {
+                "page_number": 1,
+                "text": "Page one",
+                "image_prompt": "Page one image",
+                "image_url": "https://example.com/page-1.png",
+            },
+        ],
+        cover_prompt="Storybook cover",
+        image_url="https://example.com/cover.png",
+        image_status="ready",
+        audio_status="not_requested",
+    )
+
+    assert resolve_story_generation_status(story) == StoryGenerationStatus.COMPLETED
+
+
+def test_missing_narrative_sets_text_failed():
+    story = make_story(story_text=None, pages=None)
+
+    sync_story_status(story, image_status=StoryAssetStatus.NOT_REQUESTED)
+
+    assert story.text_status == "failed"
+    assert story.generation_status == StoryGenerationStatus.FAILED.value