feat(lotto): 티켓 생성 3전략 (engine_w/random_null/coverage)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lotto/tests/test_backtest.py

@@ -2,6 +2,17 @@ from app import backtest as bt
 from app.analyzer import build_analysis_cache, score_combination
 
 
+def _toy_draws(n=120):
+    # 결정적 가짜 회차: 분석 캐시 구성용 (오름차순 (drw_no, [6 nums]))
+    import random as _r
+    _r.seed(1)
+    out = []
+    for i in range(1, n + 1):
+        nums = sorted(_r.sample(range(1, 46), 6))
+        out.append((i, nums))
+    return out
+
+
 def test_grade_tickets_histogram_and_prizes():
     winning6 = [1, 2, 3, 4, 5, 6]
     bonus = 7
@@ -23,3 +34,26 @@ def test_grade_tickets_histogram_and_prizes():
     # 등수 매핑 헬퍼
     prizes = bt.prize_counts(r)
     assert prizes == {"1st": 1, "2nd": 1, "3rd": 1, "4th": 1, "5th": 1}
+
+
+def test_purchase_tickets_distinct_and_count():
+    draws = _toy_draws()
+    cache = bt.build_analysis_cache(draws)
+    nw = bt.build_number_weights(cache)
+    pool = bt.generate_pool(cache, nw, n=2000, seed=7)
+    W = [0.25, 0.30, 0.20, 0.15, 0.10]
+    bought = bt.purchase_tickets(pool, cache, W, k=50)
+    assert len(bought) == 50
+    assert len({tuple(t) for t in bought}) == 50           # distinct
+    # W로 랭킹된 상위 → 평균 분석치가 풀 평균보다 높아야
+    avg_bought = sum(score_combination(t, cache, W)["score_total"] for t in bought) / 50
+    assert avg_bought > 0
+
+
+def test_random_null_and_coverage_distinct():
+    rnd = bt.random_null_tickets(k=50, seed=3)
+    assert len(rnd) == 50 and len({tuple(t) for t in rnd}) == 50
+    cov = bt.coverage_tickets(k=9, seed=3)   # 9장 = 54슬롯 ≥ 45번호 전수 커버 가능
+    flat = {n for t in cov for n in t}
+    assert len(cov) == 9 and len({tuple(t) for t in cov}) == 9
+    assert len(flat) >= 40   # 커버리지 전략은 번호를 넓게 퍼뜨림