"""合成零结果诊断：每次只放宽一个条件。"""
import json

rows = [{"symbol": "AAA", "pe": 18, "growth": .08},
        {"symbol": "BBB", "pe": 24, "growth": .15},
        {"symbol": "CCC", "pe": 30, "growth": None}]

def screen(pe_limit=20, growth_floor=.10):
    return [r["symbol"] for r in rows if r["growth"] is not None
            and r["pe"] < pe_limit and r["growth"] >= growth_floor]

baseline = screen()
proposals = {"pe_lt_25": screen(pe_limit=25),
             "growth_ge_0.05": screen(growth_floor=.05)}
assert baseline == []
assert proposals == {"pe_lt_25": ["BBB"], "growth_ge_0.05": ["AAA"]}
assert screen(growth_floor=10) == []
assert sum(r["growth"] is None for r in rows) == 1
assert screen() == baseline
print(json.dumps({"baseline": baseline, "relax_one": proposals,
                  "growth_coverage": "2/3", "unit_error_floor": 10}))