test_layer1_of_target_range.py

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"""Layer 1 refuses a target O/F outside the propellant's CEA table instead of optimizing garbage."""
 
import pytest
 
from engine.optimizer.layers.layer1_static_optimization import _layer1_check_of_target_in_cea_range
from engine.pipeline.config_switch import load_canonical_config, apply_propellant
from engine.pipeline.config_schemas import PintleEngineConfig
 
 
def _ethalox_pintle():
    return PintleEngineConfig(**load_canonical_config("pintle"))   # ethalox, MR_range [1.0, 2.5]
 
 
def test_in_range_target_passes():
    cfg = _ethalox_pintle()
    lo, hi = cfg.combustion.cea.MR_range
    _layer1_check_of_target_in_cea_range(cfg, 0.5 * (lo + hi))
    _layer1_check_of_target_in_cea_range(cfg, lo)
    _layer1_check_of_target_in_cea_range(cfg, hi)
 
 
def test_out_of_range_target_is_refused_with_the_fix_in_the_message():
    cfg = _ethalox_pintle()
    with pytest.raises(ValueError, match=r"outside the CEA table for ethalox .*\‍[1\.00, 2\.50\‍]"):
        _layer1_check_of_target_in_cea_range(cfg, 3.5)
 
 
def test_stale_target_after_propellant_switch_is_caught():
    """The ethalox canonical carries optimal_of_ratio 1.4. A methalox overlay (table 2.4-4.2) now
    moves the target to the preset's design O/F (DEF-06), which the check accepts; an ethalox
    target put back on the methalox design must still be refused, not pinned at the table edge."""
    switched = PintleEngineConfig(**apply_propellant(load_canonical_config("pintle"), "methalox"))
    assert switched.design_requirements.optimal_of_ratio == pytest.approx(2.8)
    _layer1_check_of_target_in_cea_range(switched, switched.design_requirements.optimal_of_ratio)
    with pytest.raises(ValueError, match="outside the CEA table for methalox"):
        _layer1_check_of_target_in_cea_range(switched, 1.4)
 
 
def test_missing_table_range_does_not_block():
    cfg = _ethalox_pintle()
    cfg.combustion.cea.MR_range = None
    _layer1_check_of_target_in_cea_range(cfg, 99.0)