feat(stars): sync implement unified purchase flow

internal/compat/android/stars_test.go

@@ -0,0 +1,30 @@
+package android
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestDirectInvoiceCurrenciesAreStableAndContainUSD(t *testing.T) {
+	values := DirectInvoiceCurrencies()
+	if len(values) == 0 {
+		t.Fatal("direct invoice currency list is empty")
+	}
+	foundUSD := false
+	for _, value := range values {
+		if value == "USD" {
+			foundUSD = true
+		}
+	}
+	if !foundUSD {
+		t.Fatalf("direct invoice currencies = %v, want USD", values)
+	}
+	values[0] = "MUTATED"
+	if DirectInvoiceCurrencies()[0] == "MUTATED" {
+		t.Fatal("DirectInvoiceCurrencies returned mutable package storage")
+	}
+	var decoded []string
+	if err := json.Unmarshal([]byte(DirectInvoiceCurrenciesJSON()), &decoded); err != nil || len(decoded) != len(values) {
+		t.Fatalf("currency JSON = %q decoded=%v err=%v", DirectInvoiceCurrenciesJSON(), decoded, err)
+	}
+}