nutrition field

services/nutritionResponse_test.go

@@ -0,0 +1,148 @@
+package services
+
+import (
+	"encoding/json"
+	"testing"
+
+	"nearle/models"
+)
+
+/*
+What the product screen receives.
+
+The app renders a nutrition panel off `getproductbyvariant`. These are about the
+contract that screen is built on — the exact field names, and what happens for
+the overwhelming majority of products, which have no structured nutrition at all
+and are not going to for a while.
+*/
+
+func TestTheStructuredPanelIsUsedWhereItExists(t *testing.T) {
+	facts := `{"nutrition":{"per":"100g","servingsize":"30g","items":[
+		{"name":"Energy","value":520,"unit":"kcal"},
+		{"name":"Protein","value":6.5,"unit":"g"}]}}`
+
+	panel := nutritionFromFacts(facts)
+	if !panel.HasValues() {
+		t.Fatal("no panel")
+	}
+	if panel.Per != "100g" || panel.Servingsize != "30g" {
+		t.Fatalf("basis lost: per=%q servingsize=%q", panel.Per, panel.Servingsize)
+	}
+	if len(panel.Items) != 2 || panel.Items[1].Value != 6.5 {
+		t.Fatalf("items wrong: %+v", panel.Items)
+	}
+}
+
+func TestTheOldNutrientLinesStillProduceAPanel(t *testing.T) {
+	// This is the case that actually matters on day one: every product on the
+	// platform carries display lines and nothing else. Without this the app
+	// ships a nutrition screen that is empty for every product in every shop.
+	panel := nutritionFromFacts(`{"nutrients":["Energy 350kcal","Protein 7g"]}`)
+	if !panel.HasValues() {
+		t.Fatal("the lines were not used")
+	}
+	if panel.Items[0].Name != "Energy" || panel.Items[0].Value != 350 {
+		t.Fatalf("got %+v", panel.Items[0])
+	}
+}
+
+func TestStructuredBeatsLinesWhenBothArePresent(t *testing.T) {
+	// The import keeps both — the console shows the lines, the app shows the
+	// panel. The structured one is the agent team's work and carries a basis,
+	// so it wins.
+	facts := `{"nutrients":["Energy 350kcal"],
+	           "nutrition":{"per":"100g","items":[{"name":"Energy","value":520,"unit":"kcal"}]}}`
+
+	panel := nutritionFromFacts(facts)
+	if panel.Per != "100g" || panel.Items[0].Value != 520 {
+		t.Fatalf("the derived panel won: %+v", panel)
+	}
+}
+
+func TestNothingKnownMeansNoPanel(t *testing.T) {
+	for _, facts := range []string{"", "   ", "{}", `{"highlights":["Crunchy"]}`} {
+		if p := nutritionFromFacts(facts); p != nil {
+			t.Errorf("%q produced a panel: %+v", facts, p)
+		}
+	}
+}
+
+func TestAMalformedSnapshotCostsThePanelAndNothingElse(t *testing.T) {
+	// One bad blob must not fail the response for the variant group it is in —
+	// the shopper tapped a product and is owed the screen.
+	if p := nutritionFromFacts(`{"nutrition":{"items":`); p != nil {
+		t.Fatalf("read a panel out of broken JSON: %+v", p)
+	}
+}
+
+func TestAPanelWithNoRowsIsNotSent(t *testing.T) {
+	// `items: []` renders as an empty box, which a shopper reads as "this food
+	// has no nutrition" rather than "we do not know".
+	if p := nutritionFromFacts(`{"nutrition":{"per":"100g","items":[]}}`); p != nil {
+		t.Fatalf("sent an empty panel: %+v", p)
+	}
+}
+
+func TestEveryRowInAVariantGroupIsDecorated(t *testing.T) {
+	// A shopper switching from 500ml to 1L must not watch the nutrition vanish.
+	rows := []models.Products{
+		{Productid: 1, Cataloguefacts: `{"nutrients":["Energy 350kcal"]}`},
+		{Productid: 2, Cataloguefacts: `{"nutrition":{"per":"100g","items":[{"name":"Energy","value":700,"unit":"kcal"}]}}`},
+		{Productid: 3},
+	}
+	decorateNutrition(rows)
+
+	if !rows[0].Nutrition.HasValues() || !rows[1].Nutrition.HasValues() {
+		t.Fatal("a sibling was left without its panel")
+	}
+	if rows[2].Nutrition != nil {
+		t.Fatal("invented a panel for a product with no facts")
+	}
+}
+
+func TestTheWireNamesAreTheOnesTheAppAskedFor(t *testing.T) {
+	// An API is a promise to a client already written against it. `servingsize`
+	// is not how the rest of this file would spell it, and it is what was asked
+	// for, which outranks house style.
+	rows := []models.Products{{
+		Productid:      7093,
+		Cataloguefacts: `{"nutrition":{"per":"100g","servingsize":"30g","items":[{"name":"Energy","value":520,"unit":"kcal"}]}}`,
+	}}
+	decorateNutrition(rows)
+
+	encoded, err := json.Marshal(rows[0])
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	var out map[string]any
+	if err := json.Unmarshal(encoded, &out); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+
+	nutrition, ok := out["nutrition"].(map[string]any)
+	if !ok {
+		t.Fatalf("no `nutrition` key on the product: %s", encoded)
+	}
+	for _, key := range []string{"per", "servingsize", "items"} {
+		if _, ok := nutrition[key]; !ok {
+			t.Errorf("missing %q: %v", key, nutrition)
+		}
+	}
+	item := nutrition["items"].([]any)[0].(map[string]any)
+	for _, key := range []string{"name", "value", "unit"} {
+		if _, ok := item[key]; !ok {
+			t.Errorf("item missing %q: %v", key, item)
+		}
+	}
+}
+
+func TestAProductWithNoNutritionHasNoKeyAtAll(t *testing.T) {
+	// Not `"nutrition": null`. Most products have none, and a null on every row
+	// of a mobile response is payload spent saying nothing.
+	encoded, _ := json.Marshal(models.Products{Productid: 1})
+	var out map[string]any
+	_ = json.Unmarshal(encoded, &out)
+	if _, present := out["nutrition"]; present {
+		t.Fatalf("an absent panel was sent as a key: %s", encoded)
+	}
+}