feat: complete remaining Go backend modules

backend/internal/postgres/billing_defaults_test.go

@@ -0,0 +1,33 @@
+package postgres
+
+import (
+	"context"
+	"encoding/json"
+	"reflect"
+	"strings"
+	"testing"
+
+	"git.nianxx.cn/wangxuming/NianAIGC/backend/internal/billing"
+)
+
+func TestSeedBillingPriceRulesUsesOneIdempotentUpsert(t *testing.T) {
+	q := &fakeQuerier{}
+	db := NewDatabase(Config{Backend: BackendPostgres}, q)
+	rules := []billing.PriceRule{{ID: "r", Provider: "seedance", Capability: "video.generate", ReqKey: "m", VariantKey: "resolution=720p", Unit: billing.UnitVideoSecond, StandardUnitPriceFen: 99, MarkupMultiplier: 1.2, Enabled: true}}
+	if err := db.SeedBillingPriceRules(context.Background(), rules); err != nil {
+		t.Fatal(err)
+	}
+	if q.sql != SeedBillingPriceRulesSQL || !strings.Contains(q.sql, "ON CONFLICT (provider, capability, COALESCE(req_key, ''), COALESCE(variant_key, ''), COALESCE(conditions, '{}'::jsonb)) DO UPDATE") {
+		t.Fatalf("sql = %q", q.sql)
+	}
+	if len(q.args) != 1 {
+		t.Fatalf("args = %#v", q.args)
+	}
+	var decoded []billing.PriceRule
+	if err := json.Unmarshal(q.args[0].([]byte), &decoded); err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(decoded, rules) {
+		t.Fatalf("payload = %#v", decoded)
+	}
+}