Merge pull request #517 from willmiao/codex/determine-example_images_path-structure

feat: namespace example image storage by library

py/routes/handlers/misc_handlers.py

@@ -11,7 +11,6 @@ from __future__ import annotations
 import asyncio
 import logging
 import os
-import re
 import subprocess
 import sys
 from dataclasses import dataclass
@@ -29,6 +28,7 @@ from ...services.settings_manager import settings as default_settings
 from ...services.websocket_manager import ws_manager
 from ...services.downloader import get_downloader
 from ...utils.constants import DEFAULT_NODE_COLOR, NODE_TYPES, SUPPORTED_MEDIA_EXTENSIONS
+from ...utils.example_images_paths import is_valid_example_images_root
 from ...utils.lora_metadata import extract_trained_words
 from ...utils.usage_stats import UsageStats
 
@@ -274,21 +274,7 @@ class SettingsHandler:
         return None
 
     def _is_dedicated_example_images_folder(self, folder_path: str) -> bool:
-        try:
-            items = os.listdir(folder_path)
-            if not items:
-                return True
-            for item in items:
-                item_path = os.path.join(folder_path, item)
-                if item == ".download_progress.json" and os.path.isfile(item_path):
-                    continue
-                if os.path.isdir(item_path) and re.fullmatch(r"[a-fA-F0-9]{64}", item):
-                    continue
-                return False
-            return True
-        except Exception as exc:  # pragma: no cover - defensive logging
-            logger.error("Error checking if folder is dedicated: %s", exc)
-            return False
+        return is_valid_example_images_root(folder_path)
 
 
 class UsageStatsHandler:

py/services/example_images_cleanup_service.py

@@ -8,10 +8,11 @@ import os
 import shutil
 from dataclasses import dataclass
 from pathlib import Path
-from typing import Dict, List
+from typing import Dict, List, Tuple
 
 from .service_registry import ServiceRegistry
 from .settings_manager import settings
+from ..utils.example_images_paths import iter_library_roots
 
 
 logger = logging.getLogger(__name__)
@@ -70,9 +71,9 @@ class ExampleImagesCleanupService:
                 "error_code": "path_not_configured",
             }
 
-        example_root = Path(example_images_path)
-        if not example_root.exists():
-            logger.debug("Cleanup skipped: example images path missing -> %s", example_root)
+        base_root = Path(example_images_path)
+        if not base_root.exists():
+            logger.debug("Cleanup skipped: example images path missing -> %s", base_root)
             return {
                 "success": False,
                 "error": "Example images path does not exist.",
@@ -91,9 +92,6 @@ class ExampleImagesCleanupService:
                 "error_code": "scanner_initialization_failed",
             }
 
-        deleted_bucket = example_root / self._deleted_folder_name
-        deleted_bucket.mkdir(exist_ok=True)
-
         checked_folders = 0
         moved_empty = 0
         moved_orphaned = 0
@@ -101,45 +99,96 @@ class ExampleImagesCleanupService:
         move_failures = 0
         errors: List[str] = []
 
-        for entry in os.scandir(example_root):
-            if not entry.is_dir(follow_symlinks=False):
+        resolved_base = base_root.resolve()
+        library_paths: List[Tuple[str, Path]] = []
+        processed_paths = {resolved_base}
+
+        for library_name, library_path in iter_library_roots():
+            if not library_path:
                 continue
-
-            if entry.name == self._deleted_folder_name:
-                continue
-
-            checked_folders += 1
-            folder_path = Path(entry.path)
-
+            library_root = Path(library_path)
             try:
-                if self._is_folder_empty(folder_path):
-                    if await self._remove_empty_folder(folder_path):
-                        moved_empty += 1
-                    else:
-                        move_failures += 1
-                    continue
-
-                if not self._is_hash_folder(entry.name):
-                    skipped_non_hash += 1
-                    continue
-
-                hash_exists = (
-                    lora_scanner.has_hash(entry.name)
-                    or checkpoint_scanner.has_hash(entry.name)
-                    or embedding_scanner.has_hash(entry.name)
+                resolved = library_root.resolve()
+            except FileNotFoundError:
+                continue
+            if resolved in processed_paths:
+                continue
+            if not library_root.exists():
+                logger.debug(
+                    "Skipping cleanup for library '%s': folder missing (%s)",
+                    library_name,
+                    library_root,
                 )
+                continue
+            processed_paths.add(resolved)
+            library_paths.append((library_name, library_root))
 
-                if not hash_exists:
-                    if await self._move_folder(folder_path, deleted_bucket):
-                        moved_orphaned += 1
-                    else:
-                        move_failures += 1
+        deleted_roots: List[Path] = []
 
-            except Exception as exc:  # pragma: no cover - filesystem guard
-                move_failures += 1
-                error_message = f"{entry.name}: {exc}"
-                errors.append(error_message)
-                logger.error("Error processing example images folder %s: %s", folder_path, exc, exc_info=True)
+        # Build list of (label, root) pairs including the base root for legacy layouts
+        cleanup_targets: List[Tuple[str, Path]] = [("__base__", base_root)] + library_paths
+
+        library_root_set = {root.resolve() for _, root in library_paths}
+
+        for label, root_path in cleanup_targets:
+            deleted_bucket = root_path / self._deleted_folder_name
+            deleted_bucket.mkdir(exist_ok=True)
+            deleted_roots.append(deleted_bucket)
+
+            for entry in os.scandir(root_path):
+                if not entry.is_dir(follow_symlinks=False):
+                    continue
+
+                if entry.name == self._deleted_folder_name:
+                    continue
+
+                entry_path = Path(entry.path)
+
+                if label == "__base__":
+                    try:
+                        resolved_entry = entry_path.resolve()
+                    except FileNotFoundError:
+                        continue
+                    if resolved_entry in library_root_set:
+                        # Skip library-specific folders tracked separately
+                        continue
+
+                checked_folders += 1
+
+                try:
+                    if self._is_folder_empty(entry_path):
+                        if await self._remove_empty_folder(entry_path):
+                            moved_empty += 1
+                        else:
+                            move_failures += 1
+                        continue
+
+                    if not self._is_hash_folder(entry.name):
+                        skipped_non_hash += 1
+                        continue
+
+                    hash_exists = (
+                        lora_scanner.has_hash(entry.name)
+                        or checkpoint_scanner.has_hash(entry.name)
+                        or embedding_scanner.has_hash(entry.name)
+                    )
+
+                    if not hash_exists:
+                        if await self._move_folder(entry_path, deleted_bucket):
+                            moved_orphaned += 1
+                        else:
+                            move_failures += 1
+
+                except Exception as exc:  # pragma: no cover - filesystem guard
+                    move_failures += 1
+                    error_message = f"{entry.name}: {exc}"
+                    errors.append(error_message)
+                    logger.error(
+                        "Error processing example images folder %s: %s",
+                        entry_path,
+                        exc,
+                        exc_info=True,
+                    )
 
         partial_success = move_failures > 0 and (moved_empty > 0 or moved_orphaned > 0)
         success = move_failures == 0 and not errors
@@ -152,11 +201,12 @@ class ExampleImagesCleanupService:
             skipped_non_hash=skipped_non_hash,
             move_failures=move_failures,
             errors=errors,
-            deleted_root=str(deleted_bucket),
+            deleted_root=str(deleted_roots[0]) if deleted_roots else None,
             partial_success=partial_success,
         )
 
         summary = result.to_dict()
+        summary["deleted_roots"] = [str(path) for path in deleted_roots]
         if success:
             logger.info(
                 "Example images cleanup complete: checked=%s, moved_empty=%s, moved_orphaned=%s",

py/utils/example_images_download_manager.py

@@ -8,6 +8,7 @@ import time
 from typing import Any, Dict
 
 from ..services.service_registry import ServiceRegistry
+from ..utils.example_images_paths import ensure_library_root_exists
 from ..utils.metadata_manager import MetadataManager
 from .example_images_processor import ExampleImagesProcessor
 from .example_images_metadata import MetadataUpdater
@@ -84,6 +85,13 @@ class DownloadManager:
         self._ws_manager = ws_manager
         self._state_lock = state_lock or asyncio.Lock()
 
+    def _resolve_output_dir(self) -> str:
+        base_path = settings.get('example_images_path')
+        if not base_path:
+            return ''
+        library_name = settings.get_active_library_name()
+        return ensure_library_root_exists(library_name)
+
     async def start_download(self, options: dict):
         """Start downloading example images for models."""
 
@@ -98,9 +106,9 @@ class DownloadManager:
                 model_types = data.get('model_types', ['lora', 'checkpoint'])
                 delay = float(data.get('delay', 0.2))
 
-                output_dir = settings.get('example_images_path')
+                base_path = settings.get('example_images_path')
 
-                if not output_dir:
+                if not base_path:
                     error_msg = 'Example images path not configured in settings'
                     if auto_mode:
                         logger.debug(error_msg)
@@ -110,7 +118,9 @@ class DownloadManager:
                         }
                     raise DownloadConfigurationError(error_msg)
 
-                os.makedirs(output_dir, exist_ok=True)
+                output_dir = self._resolve_output_dir()
+                if not output_dir:
+                    raise DownloadConfigurationError('Example images path not configured in settings')
 
                 self._progress.reset()
                 self._progress['status'] = 'running'
@@ -458,13 +468,14 @@ class DownloadManager:
             if not model_hashes:
                 raise DownloadConfigurationError('Missing model_hashes parameter')
 
-            output_dir = settings.get('example_images_path')
+            base_path = settings.get('example_images_path')
 
+            if not base_path:
+                raise DownloadConfigurationError('Example images path not configured in settings')
+            output_dir = self._resolve_output_dir()
             if not output_dir:
                 raise DownloadConfigurationError('Example images path not configured in settings')
 
-            os.makedirs(output_dir, exist_ok=True)
-
             self._progress.reset()
             self._progress['total'] = len(model_hashes)
             self._progress['status'] = 'running'

py/utils/example_images_file_manager.py

@@ -4,6 +4,10 @@ import sys
 import subprocess
 from aiohttp import web
 from ..services.settings_manager import settings
+from ..utils.example_images_paths import (
+    get_model_folder,
+    get_model_relative_path,
+)
 from ..utils.constants import SUPPORTED_MEDIA_EXTENSIONS
 
 logger = logging.getLogger(__name__)
@@ -41,8 +45,12 @@ class ExampleImagesFileManager:
                 }, status=400)
             
             # Construct folder path for this model
-            model_folder = os.path.join(example_images_path, model_hash)
-            model_folder = os.path.abspath(model_folder)  # Get absolute path
+            model_folder = get_model_folder(model_hash)
+            if not model_folder:
+                return web.json_response({
+                    'success': False,
+                    'error': 'Failed to resolve example images folder for this model.'
+                }, status=500)
 
             # Path validation: ensure model_folder is under example_images_path
             if not model_folder.startswith(os.path.abspath(example_images_path)):
@@ -109,8 +117,13 @@ class ExampleImagesFileManager:
                 }, status=400)
             
             # Construct folder path for this model
-            model_folder = os.path.join(example_images_path, model_hash)
-            
+            model_folder = get_model_folder(model_hash)
+            if not model_folder:
+                return web.json_response({
+                    'success': False,
+                    'error': 'Failed to resolve example images folder for this model'
+                }, status=500)
+
             # Check if folder exists
             if not os.path.exists(model_folder):
                 return web.json_response({
@@ -128,9 +141,10 @@ class ExampleImagesFileManager:
                     file_ext = os.path.splitext(file)[1].lower()
                     if (file_ext in SUPPORTED_MEDIA_EXTENSIONS['images'] or 
                         file_ext in SUPPORTED_MEDIA_EXTENSIONS['videos']):
+                        relative_path = get_model_relative_path(model_hash)
                         files.append({
                             'name': file,
-                            'path': f'/example_images_static/{model_hash}/{file}',
+                            'path': f'/example_images_static/{relative_path}/{file}',
                             'extension': file_ext,
                             'is_video': file_ext in SUPPORTED_MEDIA_EXTENSIONS['videos']
                         })
@@ -176,8 +190,13 @@ class ExampleImagesFileManager:
                 })
             
             # Construct folder path for this model
-            model_folder = os.path.join(example_images_path, model_hash)
-            
+            model_folder = get_model_folder(model_hash)
+            if not model_folder:
+                return web.json_response({
+                    'has_images': False,
+                    'error': 'Failed to resolve example images folder for this model'
+                })
+
             # Check if folder exists
             if not os.path.exists(model_folder) or not os.path.isdir(model_folder):
                 return web.json_response({

py/utils/example_images_migration.py

@@ -5,6 +5,7 @@ import re
 import json
 from ..services.settings_manager import settings
 from ..services.service_registry import ServiceRegistry
+from ..utils.example_images_paths import iter_library_roots
 from ..utils.metadata_manager import MetadataManager
 from ..utils.example_images_processor import ExampleImagesProcessor
 from ..utils.constants import SUPPORTED_MEDIA_EXTENSIONS
@@ -19,29 +20,35 @@ class ExampleImagesMigration:
     @staticmethod
     async def check_and_run_migrations():
         """Check if migrations are needed and run them in background"""
-        example_images_path = settings.get('example_images_path')
-        if not example_images_path or not os.path.exists(example_images_path):
+        root = settings.get('example_images_path')
+        if not root or not os.path.exists(root):
             logger.debug("No example images path configured or path doesn't exist, skipping migrations")
             return
-        
-        # Check current version from progress file
-        current_version = 0
-        progress_file = os.path.join(example_images_path, '.download_progress.json')
-        if os.path.exists(progress_file):
-            try:
-                with open(progress_file, 'r', encoding='utf-8') as f:
-                    progress_data = json.load(f)
-                    current_version = progress_data.get('naming_version', 0)
-            except Exception as e:
-                logger.error(f"Failed to load progress file for migration check: {e}")
-        
-        # If current version is less than target version, start migration
-        if current_version < CURRENT_NAMING_VERSION:
-            logger.info(f"Starting example images naming migration from v{current_version} to v{CURRENT_NAMING_VERSION}")
-            # Start migration in background task
-            asyncio.create_task(
-                ExampleImagesMigration.run_migrations(example_images_path, current_version, CURRENT_NAMING_VERSION)
-            )
+
+        for library_name, library_path in iter_library_roots():
+            if not library_path or not os.path.exists(library_path):
+                continue
+
+            current_version = 0
+            progress_file = os.path.join(library_path, '.download_progress.json')
+            if os.path.exists(progress_file):
+                try:
+                    with open(progress_file, 'r', encoding='utf-8') as f:
+                        progress_data = json.load(f)
+                        current_version = progress_data.get('naming_version', 0)
+                except Exception as e:
+                    logger.error(f"Failed to load progress file for migration check: {e}")
+
+            if current_version < CURRENT_NAMING_VERSION:
+                logger.info(
+                    "Starting example images naming migration from v%s to v%s for library '%s'",
+                    current_version,
+                    CURRENT_NAMING_VERSION,
+                    library_name,
+                )
+                asyncio.create_task(
+                    ExampleImagesMigration.run_migrations(library_path, current_version, CURRENT_NAMING_VERSION)
+                )
     
     @staticmethod
     async def run_migrations(example_images_path, from_version, to_version):

py/utils/example_images_paths.py

@@ -0,0 +1,193 @@
+"""Utility helpers for resolving example image storage paths."""
+
+from __future__ import annotations
+
+import logging
+import os
+import re
+import shutil
+from typing import Iterable, List, Optional, Tuple
+
+from ..services.settings_manager import settings
+
+_HEX_PATTERN = re.compile(r"[a-fA-F0-9]{64}")
+
+logger = logging.getLogger(__name__)
+
+
+def _get_configured_libraries() -> List[str]:
+    """Return configured library names if multi-library support is enabled."""
+
+    libraries = settings.get("libraries")
+    if isinstance(libraries, dict) and libraries:
+        return list(libraries.keys())
+    return []
+
+
+def get_example_images_root() -> str:
+    """Return the root directory configured for example images."""
+
+    root = settings.get("example_images_path") or ""
+    return os.path.abspath(root) if root else ""
+
+
+def uses_library_scoped_folders() -> bool:
+    """Return True when example images should be separated per library."""
+
+    libraries = _get_configured_libraries()
+    return len(libraries) > 1
+
+
+def sanitize_library_name(library_name: Optional[str]) -> str:
+    """Return a filesystem safe library name."""
+
+    name = library_name or settings.get_active_library_name() or "default"
+    safe_name = re.sub(r"[^A-Za-z0-9_.-]", "_", name)
+    return safe_name or "default"
+
+
+def get_library_root(library_name: Optional[str] = None) -> str:
+    """Return the directory where a library's example images should live."""
+
+    root = get_example_images_root()
+    if not root:
+        return ""
+
+    if uses_library_scoped_folders():
+        return os.path.join(root, sanitize_library_name(library_name))
+    return root
+
+
+def ensure_library_root_exists(library_name: Optional[str] = None) -> str:
+    """Ensure the example image directory for a library exists and return it."""
+
+    library_root = get_library_root(library_name)
+    if library_root:
+        os.makedirs(library_root, exist_ok=True)
+    return library_root
+
+
+def get_model_folder(model_hash: str, library_name: Optional[str] = None) -> str:
+    """Return the folder path for a model's example images."""
+
+    if not model_hash:
+        return ""
+
+    library_root = ensure_library_root_exists(library_name)
+    if not library_root:
+        return ""
+
+    normalized_hash = (model_hash or "").lower()
+    resolved_folder = os.path.join(library_root, normalized_hash)
+
+    if uses_library_scoped_folders():
+        legacy_root = get_example_images_root()
+        legacy_folder = os.path.join(legacy_root, normalized_hash)
+        if os.path.exists(legacy_folder) and not os.path.exists(resolved_folder):
+            try:
+                os.makedirs(library_root, exist_ok=True)
+                shutil.move(legacy_folder, resolved_folder)
+                logger.info(
+                    "Migrated legacy example images folder '%s' to '%s'", legacy_folder, resolved_folder
+                )
+            except OSError as exc:
+                logger.error(
+                    "Failed to migrate example images from '%s' to '%s': %s",
+                    legacy_folder,
+                    resolved_folder,
+                    exc,
+                )
+                return legacy_folder
+
+    return resolved_folder
+
+
+def get_model_relative_path(model_hash: str, library_name: Optional[str] = None) -> str:
+    """Return the relative URL path from the static mount to a model folder."""
+
+    root = get_example_images_root()
+    folder = get_model_folder(model_hash, library_name)
+    if not root or not folder:
+        return ""
+
+    try:
+        relative = os.path.relpath(folder, root)
+    except ValueError:
+        return ""
+
+    return relative.replace("\\", "/")
+
+
+def iter_library_roots() -> Iterable[Tuple[str, str]]:
+    """Yield configured library names and their resolved filesystem roots."""
+
+    root = get_example_images_root()
+    if not root:
+        return []
+
+    libraries = _get_configured_libraries()
+    if uses_library_scoped_folders():
+        results: List[Tuple[str, str]] = []
+        if libraries:
+            for library in libraries:
+                results.append((library, get_library_root(library)))
+        else:
+            # Fall back to the active library to avoid skipping migrations/cleanup
+            active = settings.get_active_library_name() or "default"
+            results.append((active, get_library_root(active)))
+        return results
+
+    active = settings.get_active_library_name() or "default"
+    return [(active, root)]
+
+
+def is_hash_folder(name: str) -> bool:
+    """Return True if the provided name looks like a model hash folder."""
+
+    return bool(_HEX_PATTERN.fullmatch(name or ""))
+
+
+def is_valid_example_images_root(folder_path: str) -> bool:
+    """Check whether a folder looks like a dedicated example images root."""
+
+    try:
+        items = os.listdir(folder_path)
+    except OSError:
+        return False
+
+    for item in items:
+        item_path = os.path.join(folder_path, item)
+        if item == ".download_progress.json" and os.path.isfile(item_path):
+            continue
+
+        if os.path.isdir(item_path):
+            if is_hash_folder(item):
+                continue
+            if item == "_deleted":
+                # Allow cleanup staging folders
+                continue
+            # When multi-library mode is active we expect nested hash folders
+            if uses_library_scoped_folders():
+                if _library_folder_has_only_hash_dirs(item_path):
+                    continue
+        return False
+
+    return True
+
+
+def _library_folder_has_only_hash_dirs(path: str) -> bool:
+    """Return True when a library subfolder only contains hash folders or metadata files."""
+
+    try:
+        for entry in os.listdir(path):
+            entry_path = os.path.join(path, entry)
+            if entry == ".download_progress.json" and os.path.isfile(entry_path):
+                continue
+            if entry == "_deleted" and os.path.isdir(entry_path):
+                continue
+            if not os.path.isdir(entry_path) or not is_hash_folder(entry):
+                return False
+    except OSError:
+        return False
+
+    return True

py/utils/example_images_processor.py

@@ -7,6 +7,7 @@ from aiohttp import web
 from ..utils.constants import SUPPORTED_MEDIA_EXTENSIONS
 from ..services.service_registry import ServiceRegistry
 from ..services.settings_manager import settings
+from ..utils.example_images_paths import get_model_folder, get_model_relative_path
 from .example_images_metadata import MetadataUpdater
 from ..utils.metadata_manager import MetadataManager
 
@@ -346,7 +347,9 @@ class ExampleImagesProcessor:
                 )
 
             # Create model folder
-            model_folder = os.path.join(example_images_path, model_hash)
+            model_folder = get_model_folder(model_hash)
+            if not model_folder:
+                raise ExampleImagesImportError('Failed to resolve model folder for example images')
             os.makedirs(model_folder, exist_ok=True)
 
             imported_files = []
@@ -383,7 +386,7 @@ class ExampleImagesProcessor:
                     # Add to imported files list
                     imported_files.append({
                         'name': new_filename,
-                        'path': f'/example_images_static/{model_hash}/{new_filename}',
+                        'path': f'/example_images_static/{get_model_relative_path(model_hash)}/{new_filename}',
                         'extension': file_ext,
                         'is_video': file_ext in SUPPORTED_MEDIA_EXTENSIONS['videos']
                     })
@@ -497,7 +500,12 @@ class ExampleImagesProcessor:
                 }, status=404)
             
             # Find and delete the actual file
-            model_folder = os.path.join(example_images_path, model_hash)
+            model_folder = get_model_folder(model_hash)
+            if not model_folder:
+                return web.json_response({
+                    'success': False,
+                    'error': 'Failed to resolve model folder for example images'
+                }, status=500)
             file_deleted = False
             
             if os.path.exists(model_folder):

tests/utils/test_example_images_paths.py

@@ -0,0 +1,76 @@
+from __future__ import annotations
+
+import copy
+import os
+from pathlib import Path
+
+import pytest
+
+from py.services.settings_manager import settings
+from py.utils.example_images_paths import get_model_folder, get_model_relative_path
+
+
+@pytest.fixture(autouse=True)
+def restore_settings():
+    original = copy.deepcopy(settings.settings)
+    try:
+        yield
+    finally:
+        settings.settings.clear()
+        settings.settings.update(original)
+
+
+def test_get_model_folder_single_library(tmp_path):
+    settings.settings['example_images_path'] = str(tmp_path)
+    settings.settings['libraries'] = {'default': {}}
+    settings.settings['active_library'] = 'default'
+
+    model_hash = 'a' * 64
+    folder = get_model_folder(model_hash)
+    relative = get_model_relative_path(model_hash)
+
+    assert Path(folder) == tmp_path / model_hash
+    assert relative == model_hash
+
+
+def test_get_model_folder_multi_library(tmp_path):
+    settings.settings['example_images_path'] = str(tmp_path)
+    settings.settings['libraries'] = {
+        'default': {},
+        'Alt Library': {},
+    }
+    settings.settings['active_library'] = 'Alt Library'
+
+    model_hash = 'b' * 64
+    expected_folder = tmp_path / 'Alt_Library' / model_hash
+
+    folder = get_model_folder(model_hash)
+    relative = get_model_relative_path(model_hash)
+
+    assert Path(folder) == expected_folder
+    assert relative == os.path.join('Alt_Library', model_hash).replace('\\', '/')
+
+
+def test_get_model_folder_migrates_legacy_structure(tmp_path):
+    settings.settings['example_images_path'] = str(tmp_path)
+    settings.settings['libraries'] = {
+        'default': {},
+        'extra': {},
+    }
+    settings.settings['active_library'] = 'extra'
+
+    model_hash = 'c' * 64
+    legacy_folder = tmp_path / model_hash
+    legacy_folder.mkdir()
+    legacy_file = legacy_folder / 'image.png'
+    legacy_file.write_text('data', encoding='utf-8')
+
+    resolved_folder = get_model_folder(model_hash)
+    relative = get_model_relative_path(model_hash)
+
+    expected_folder = tmp_path / 'extra' / model_hash
+
+    assert Path(resolved_folder) == expected_folder
+    assert relative == os.path.join('extra', model_hash).replace('\\', '/')
+    assert not legacy_folder.exists()
+    assert (expected_folder / 'image.png').exists()