feat: complete remaining Go backend modules

backend/internal/billing/defaults_test.go

@@ -0,0 +1,32 @@
+package billing
+
+import "testing"
+
+func TestDefaultBillingPriceRulesFreezeOfficialCatalogMatchKeys(t *testing.T) {
+	rules := DefaultBillingPriceRules()
+	want := map[string]bool{
+		"base-volcengine-jimeng-seedream46": false,
+		"base-evolink-gpt-image-2":          false,
+		"base-bailian-wan27-image-pro":      false,
+		"base-bailian-wan27-i2v-720p":       false,
+		"base-bailian-wan27-i2v-1080p":      false,
+		"base-seedance-2-0-480p":            false,
+		"base-seedance-2-0-720p":            false,
+		"base-seedance-2-0-1080p":           false,
+		"base-seedance-2-0-4k":              false,
+	}
+	for _, rule := range rules {
+		if _, ok := want[rule.ID]; !ok {
+			t.Fatalf("unexpected default rule %q", rule.ID)
+		}
+		want[rule.ID] = true
+		if !rule.Enabled || rule.MarkupMultiplier != 1.2 || rule.StandardUnitPriceFen <= 0 {
+			t.Fatalf("invalid default rule %#v", rule)
+		}
+	}
+	for id, found := range want {
+		if !found {
+			t.Errorf("missing default rule %q", id)
+		}
+	}
+}