44 lines
1.6 KiB
Python
44 lines
1.6 KiB
Python
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"""Regression: PresetManager.save() must persist presets atomically.
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save() used a plain open("w") + json.dump, which truncates presets.json before
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writing the new content. A crash / power loss / serialization error mid-write
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leaves the file truncated or empty — the user loses every saved preset. The
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save now goes through core.atomic_io.atomic_write_json (tmp file + os.replace),
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which the rest of the codebase already uses for JSON state files.
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"""
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import inspect
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import json
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from src.preset_manager import PresetManager
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class _Unserializable:
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"""json.dump cannot serialize this — stands in for a mid-write failure."""
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def test_save_uses_atomic_write_json():
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src = inspect.getsource(PresetManager.save)
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assert "atomic_write_json" in src, "save() must persist via atomic_write_json"
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assert "open(" not in src, "save() must not write presets.json with a plain open('w')"
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def test_failed_save_does_not_truncate_existing_file(tmp_path):
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mgr = PresetManager(str(tmp_path))
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assert mgr.save({"custom": {"name": "keep"}}) is True
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before = (tmp_path / "presets.json").read_text(encoding="utf-8")
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# A payload that cannot be serialized must not clobber the good file.
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assert mgr.save({"custom": {"obj": _Unserializable()}}) is False
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after = (tmp_path / "presets.json").read_text(encoding="utf-8")
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assert after == before
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assert json.loads(after) == {"custom": {"name": "keep"}}
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def test_save_round_trip(tmp_path):
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mgr = PresetManager(str(tmp_path))
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assert mgr.save({"custom": {"name": "X", "temperature": 0.5}}) is True
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reloaded = PresetManager(str(tmp_path))
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assert reloaded.presets["custom"]["name"] == "X"
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