test: expand config tests — BakeryConfig/LoraConfig __post_init__ coverage

[hai-pilgrim]

Summary

Expands tests/test_config.py from 2 tests to 22, adding thorough coverage for both BakeryConfig.__post_init__ and LoraConfig.__post_init__.

New tests

TestBakeryConfigPostInit

• remove_unused_columns is always False regardless of what's passed
• String-typed float fields (learning_rate, temperature, sampling_temperature, warmup_ratio, max_grad_norm) are coerced to float — mimics HfArgumentParser.parse_yaml_file behaviour where numeric values sometimes arrive as strings
• String-typed int fields (num_trajectories, trajectory_length, logging_steps, seed) are coerced to int
• Invalid string values raise ValueError that names the offending field
• Native float values pass through unchanged
• system_prompt loaded from system_prompt_file when system_prompt is None
• Explicit system_prompt takes priority over system_prompt_file

TestLoraConfigPostInit

• target_modules="all" normalised to "all-linear"
• target_modules=["all"] normalised to "all-linear"
• target_modules=["all-linear"] normalised to "all-linear"
• target_modules="all-linear" unchanged
• Explicit module list unchanged

Test plan

All 22 tests pass (uv run pytest tests/test_config.py).

🤖 Generated with Claude Code

[marksverdhei]

Review

Good comprehensive config test coverage — this is a strict superset of #15. The parametrized coercion tests and system_prompt_file tests are particularly valuable.

Needs rebase: Now conflicts with main after #16 was merged (both modify test_config.py at the same location). Please rebase onto main and resolve the conflict — the test additions themselves are clean and ready to merge after that.

[marksverdhei]

Reviewed. Good restructuring into TestBakeryConfigPostInit and TestLoraConfigPostInit classes. The parametrized string coercion tests cover all float/int fields. Error path tests (invalid strings raising ValueError) and system_prompt_file priority logic are solid additions. Removes the old duplicate test_bakery_config_numeric_coercion. LGTM.