variants units

models/productWire_test.go

@@ -0,0 +1,71 @@
+package models
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+/*
+A missing string must reach a client as "", never as an absent key.
+
+`unitvalue` and `productunit` were both `omitempty`, and on this platform
+`unitvalue` is empty for every product — measured 2026-09-02 on R mart: 24
+products, 0 with both fields, 7 with a unit and no value. So the key vanished
+from the JSON, a client read `undefined`, and joining it to the unit rendered
+the literal text "null kg" on a shopper's screen.
+
+The same applies to money: a price of 0 is a real answer ("this has no price
+set"), and a client that receives no key at all cannot tell that from a field
+it forgot to request.
+*/
+
+func fieldsOf(t *testing.T, v any) map[string]any {
+	t.Helper()
+	raw, err := json.Marshal(v)
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	var out map[string]any
+	if err := json.Unmarshal(raw, &out); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	return out
+}
+
+func TestAnEmptyUnitIsSentAsEmptyNotOmitted(t *testing.T) {
+	got := fieldsOf(t, Products{Productid: 1})
+	for _, key := range []string{"unitvalue", "productunit"} {
+		if _, present := got[key]; !present {
+			t.Errorf("%q was omitted; a client reads that as null and renders it", key)
+		}
+	}
+}
+
+func TestAZeroPriceIsSentAsZeroNotOmitted(t *testing.T) {
+	got := fieldsOf(t, Products{Productid: 1})
+	if _, present := got["retailprice"]; !present {
+		t.Error("retailprice was omitted; 0 is a real answer and must be visible")
+	}
+}
+
+func TestAVariantAlwaysCarriesItsPriceAndUnit(t *testing.T) {
+	got := fieldsOf(t, Productvariant{Variantid: 1})
+	for _, key := range []string{"price", "variantprice", "variantunitvalue", "variantproductunit"} {
+		if _, present := got[key]; !present {
+			t.Errorf("variant option omitted %q", key)
+		}
+	}
+}
+
+func TestAProductWithNoVariantsSendsAnEmptyListNotNull(t *testing.T) {
+	// The case that lets an order proceed: [] means "order this one directly".
+	// A JSON null would force every client to null-check before counting.
+	got := fieldsOf(t, Products{Productid: 1, Variantoptions: []Productvariant{}})
+	list, ok := got["variantoptions"].([]any)
+	if !ok {
+		t.Fatalf("variantoptions was %T, want a list", got["variantoptions"])
+	}
+	if len(list) != 0 {
+		t.Errorf("expected an empty list, got %d", len(list))
+	}
+}