feat(products): compute price tiers from objective price/use

backend/tests/test_products_pricing.py

@@ -0,0 +1,177 @@
+import uuid
+
+from innercontext.api import products as products_api
+from innercontext.models import Product
+from innercontext.models.enums import DayTime, ProductCategory
+
+
+def _product(
+    *, category: ProductCategory, price_amount: float, size_ml: float
+) -> Product:
+    return Product(
+        id=uuid.uuid4(),
+        name=f"{category}-{price_amount}",
+        brand="Brand",
+        category=category,
+        recommended_time=DayTime.BOTH,
+        leave_on=True,
+        price_amount=price_amount,
+        price_currency="PLN",
+        size_ml=size_ml,
+    )
+
+
+def test_compute_pricing_outputs_groups_by_category(monkeypatch):
+    monkeypatch.setattr(products_api, "convert_to_pln", lambda amount, currency: amount)
+
+    serums = [
+        _product(category=ProductCategory.SERUM, price_amount=float(i), size_ml=35.0)
+        for i in range(10, 90, 10)
+    ]
+    cleansers = [
+        _product(
+            category=ProductCategory.CLEANSER, price_amount=float(i), size_ml=200.0
+        )
+        for i in range(40, 120, 10)
+    ]
+    outputs = products_api._compute_pricing_outputs(serums + cleansers)
+
+    serum_tiers = [outputs[p.id][0] for p in serums]
+    cleanser_tiers = [outputs[p.id][0] for p in cleansers]
+
+    assert serum_tiers[0] == "budget"
+    assert serum_tiers[-1] == "luxury"
+    assert cleanser_tiers[0] == "budget"
+    assert cleanser_tiers[-1] == "luxury"
+
+
+def test_price_tier_is_null_when_not_enough_products(client, monkeypatch):
+    monkeypatch.setattr(products_api, "convert_to_pln", lambda amount, currency: amount)
+
+    base = {
+        "brand": "B",
+        "recommended_time": "both",
+        "leave_on": True,
+        "size_ml": 35.0,
+        "price_currency": "PLN",
+    }
+    for i in range(7):
+        response = client.post(
+            "/products",
+            json={
+                **base,
+                "name": f"Serum {i}",
+                "category": "serum",
+                "price_amount": 30 + i,
+            },
+        )
+        assert response.status_code == 201
+
+    products = client.get("/products").json()
+    assert len(products) == 7
+    assert all(p["price_tier"] is None for p in products)
+    assert all(p["price_per_use_pln"] is not None for p in products)
+
+
+def test_price_tier_is_computed_on_list(client, monkeypatch):
+    monkeypatch.setattr(products_api, "convert_to_pln", lambda amount, currency: amount)
+
+    base = {
+        "brand": "B",
+        "recommended_time": "both",
+        "leave_on": True,
+        "size_ml": 35.0,
+        "price_currency": "PLN",
+        "category": "serum",
+    }
+    for i in range(8):
+        response = client.post(
+            "/products",
+            json={**base, "name": f"Serum {i}", "price_amount": 20 + i * 10},
+        )
+        assert response.status_code == 201
+
+    products = client.get("/products").json()
+    assert len(products) == 8
+    assert any(p["price_tier"] == "budget" for p in products)
+    assert any(p["price_tier"] == "luxury" for p in products)
+
+
+def test_price_tier_uses_fallback_for_medium_categories(client, monkeypatch):
+    monkeypatch.setattr(products_api, "convert_to_pln", lambda amount, currency: amount)
+
+    serum_base = {
+        "brand": "B",
+        "recommended_time": "both",
+        "leave_on": True,
+        "size_ml": 35.0,
+        "price_currency": "PLN",
+        "category": "serum",
+    }
+    for i in range(8):
+        response = client.post(
+            "/products",
+            json={**serum_base, "name": f"Serum {i}", "price_amount": 20 + i * 5},
+        )
+        assert response.status_code == 201
+
+    toner_base = {
+        "brand": "B",
+        "recommended_time": "both",
+        "leave_on": True,
+        "size_ml": 100.0,
+        "price_currency": "PLN",
+        "category": "toner",
+    }
+    for i in range(5):
+        response = client.post(
+            "/products",
+            json={**toner_base, "name": f"Toner {i}", "price_amount": 10 + i * 5},
+        )
+        assert response.status_code == 201
+
+    products = client.get("/products?category=toner").json()
+    assert len(products) == 5
+    assert all(p["price_tier"] is not None for p in products)
+    assert all(p["price_tier_source"] == "fallback" for p in products)
+
+
+def test_price_tier_stays_null_for_tiny_categories_even_with_fallback_pool(
+    client, monkeypatch
+):
+    monkeypatch.setattr(products_api, "convert_to_pln", lambda amount, currency: amount)
+
+    serum_base = {
+        "brand": "B",
+        "recommended_time": "both",
+        "leave_on": True,
+        "size_ml": 35.0,
+        "price_currency": "PLN",
+        "category": "serum",
+    }
+    for i in range(8):
+        response = client.post(
+            "/products",
+            json={**serum_base, "name": f"Serum {i}", "price_amount": 20 + i * 5},
+        )
+        assert response.status_code == 201
+
+    oil_base = {
+        "brand": "B",
+        "recommended_time": "both",
+        "leave_on": True,
+        "size_ml": 30.0,
+        "price_currency": "PLN",
+        "category": "oil",
+    }
+    for i in range(3):
+        response = client.post(
+            "/products",
+            json={**oil_base, "name": f"Oil {i}", "price_amount": 30 + i * 10},
+        )
+        assert response.status_code == 201
+
+    oils = client.get("/products?category=oil").json()
+    assert len(oils) == 3
+    assert all(p["price_tier"] is None for p in oils)
+    assert all(p["price_tier_source"] == "insufficient_data" for p in oils)