fix: isolate test artifacts from production asset registry

- Create tests/test_utils.py with utilities for consistent test workspace management
- Fix tests to use project tmp/ directory instead of system /tmp
- Ensure all AssetManager instances in tests use isolated registries
- Prevent contamination of production asset_registry.json during testing

Key changes:
- test_issue_142_asset_manager.py: Fix AssetManager() calls to use test workspaces
- test_issue_144_batch_import.py: Use create_test_workspace() and get_test_asset_config()
- test_issue_145_production_error_handler.py: Use test_workspace() context manager
- tests/test_utils.py: New utilities for isolated test environments

🤖 Generated with [Claude Code](https://claude.ai/code)

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

tests/test_utils.py

@@ -0,0 +1,98 @@
+"""
+Test utilities for consistent test workspace and registry management.
+
+This module provides utilities to ensure all tests use project tmp/ directory
+and isolated test registries to prevent contamination of production assets.
+"""
+
+import time
+import shutil
+from contextlib import contextmanager
+from pathlib import Path
+from typing import Optional, Dict, Any
+
+from markitect.assets.constants import (
+    DEFAULT_TEST_ASSETS_DIR,
+    DEFAULT_TEST_REGISTRY_FILENAME
+)
+
+
+def get_project_root() -> Path:
+    """Get the project root directory."""
+    return Path(__file__).parent.parent
+
+
+def create_test_workspace(prefix: str = "test") -> Path:
+    """Create a test workspace in the project tmp directory.
+
+    Args:
+        prefix: Prefix for the test directory name
+
+    Returns:
+        Path to the created test workspace
+    """
+    project_root = get_project_root()
+    temp_dir = project_root / "tmp" / "test_artifacts" / f"{prefix}_{int(time.time() * 1000000)}"
+    temp_dir.mkdir(parents=True, exist_ok=True)
+    return temp_dir
+
+
+@contextmanager
+def test_workspace(prefix: str = "test"):
+    """Context manager for test workspace that auto-cleans up.
+
+    Args:
+        prefix: Prefix for the test directory name
+
+    Yields:
+        Path to the test workspace
+    """
+    temp_dir = create_test_workspace(prefix)
+    try:
+        yield temp_dir
+    finally:
+        shutil.rmtree(temp_dir, ignore_errors=True)
+
+
+def get_test_asset_config(workspace_dir: Path,
+                         registry_name: Optional[str] = None) -> Dict[str, Any]:
+    """Get asset configuration for testing that uses isolated test paths.
+
+    Args:
+        workspace_dir: The test workspace directory
+        registry_name: Optional custom registry filename
+
+    Returns:
+        Configuration dictionary for AssetManager
+    """
+    if registry_name is None:
+        registry_name = "test_registry.json"
+
+    return {
+        "assets": {
+            "storage_path": str(workspace_dir / "assets"),
+            "registry_path": str(workspace_dir / registry_name),
+            "database_path": str(workspace_dir / "test_assets.db"),
+            "enable_deduplication": True,
+            "default_conflict_resolution": "backup"
+        }
+    }
+
+
+def ensure_test_tmp_structure():
+    """Ensure the test tmp directory structure exists."""
+    project_root = get_project_root()
+    test_artifacts_dir = project_root / "tmp" / "test_artifacts"
+    test_artifacts_dir.mkdir(parents=True, exist_ok=True)
+    return test_artifacts_dir
+
+
+# Backward compatibility functions for existing tests
+def temp_workspace():
+    """Backward compatibility alias for test_workspace()."""
+    return test_workspace()
+
+
+def create_temp_workspace():
+    """Backward compatibility alias for create_test_workspace()."""
+    return create_test_workspace()