added combined discount for consumer so codes can be calculated on the fly for any monitor

tests/test_build_product_details.py

@@ -0,0 +1,105 @@
+"""unit test: build_product_details thresholding, promo read, and combined_discount
+
+run from the repo root:
+    uv run pytest tests/test_build_product_details.py
+
+pure and offline — no Mongo. Builds a Product from a raw doc dict and checks the
+discount threshold (with percentage codes compounding onto the sale price), the
+promo fields read through via .get, and the combined_discount helper.
+"""
+
+from datetime import datetime, timezone
+
+from monitor_utils.runner import build_product_details, combined_discount
+
+
+def _doc(**overrides) -> dict:
+    """A well-formed product doc; override prices/promo per test."""
+    doc = {
+        "_id": "p1_tools",
+        "title": "Widget",
+        "url": "http://x/p1",
+        "currentPrice": 80.0,
+        "originalPrice": 100.0,
+        "imageUrl": "http://img/1",
+        "customizationIndex": None,
+        "memberNonMemberComparison": None,
+        "overstockText": None,
+        "discoveredDate": datetime(2026, 7, 26, tzinfo=timezone.utc),
+        "startDate": None,
+        "endDate": None,
+        "priceBeforeDrop": None,
+        "eduPrice": None,
+        "available": True,
+        "condition": None,
+        "appExclusive": None,
+        "memberPick": None,
+        "memberDeal": None,
+    }
+    doc.update(overrides)
+    return doc
+
+
+# ------------------------------------------------------------ combined_discount
+
+
+def test_combined_discount_no_promo_is_base():
+    assert combined_discount(24, None) == 24
+    assert combined_discount(24, 0) == 24
+
+
+def test_combined_discount_compounds_not_adds():
+    # 20% off then extra 30% code -> 44% off list (customer pays $56), not 50%
+    assert combined_discount(20, 30) == 44
+
+
+def test_combined_discount_rounds_to_nearest():
+    # 24% sale + 22% code: 1 - .76*.78 = .4072 -> 41 (rounded, not truncated 40)
+    assert combined_discount(24, 22) == 41
+
+
+# --------------------------------------------------------- build_product_details
+
+
+def test_promo_fields_read_through():
+    doc = _doc(
+        promoCode="BIRTHDAY26",
+        promoPercentage=22,
+        promoDollarOff=None,
+        promoMinSpend=None,
+    )
+    product = build_product_details(doc, min_percentage=0)
+    assert product.metadata.promo_code == "BIRTHDAY26"
+    assert product.metadata.promo_percentage == 22
+    # base percentage is the raw price delta, unchanged by the code
+    assert product.metadata.percentage == 20
+
+
+def test_missing_promo_keys_default_to_none():
+    """a doc from a lagging monitor lacks promo keys -> None, not KeyError"""
+    product = build_product_details(_doc(), min_percentage=0)
+    assert product.metadata.promo_code is None
+    assert product.metadata.promo_percentage is None
+
+
+def test_percentage_code_lifts_item_over_threshold():
+    # 30% base fails min 40, but +22% code -> 45% combined clears it
+    doc = _doc(currentPrice=70.0, originalPrice=100.0, promoPercentage=22)
+    assert build_product_details(doc, min_percentage=40) is not None
+
+
+def test_below_threshold_without_code_is_skipped():
+    doc = _doc(currentPrice=70.0, originalPrice=100.0)  # 30%, no code
+    assert build_product_details(doc, min_percentage=40) is None
+
+
+def test_dollar_code_does_not_affect_threshold():
+    # a dollar code has no promoPercentage, so 30% base stays below min 40
+    doc = _doc(
+        currentPrice=70.0,
+        originalPrice=100.0,
+        promoCode="STORE22",
+        promoDollarOff=22,
+        promoMinSpend=100,
+    )
+    assert build_product_details(doc, min_percentage=40) is None