feat: add billing and usage domain cores

backend/internal/postgres/billing_test.go

@@ -0,0 +1,29 @@
+package postgres
+
+import (
+	"context"
+	"reflect"
+	"testing"
+
+	"git.nianxx.cn/wangxuming/NianAIGC/backend/internal/billing"
+)
+
+func TestBillingWalletPosterDelegatesToExistingDatabaseFunction(t *testing.T) {
+	db := NewDatabase(Config{Backend: BackendPostgres}, &fakeQuerier{rows: [][]any{{"ledger-1", int64(75), int64(75), int64(100), int64(25), nil, nil, int64(-25)}}})
+	got, err := NewBillingWalletPoster(db).PostWalletEntry(context.Background(), billing.WalletPostParams{LedgerID: "ledger-1", OrganizationID: "org", AccountID: "a", JobID: "job", Kind: "charge", DeltaFen: -25, Currency: "CNY", IdempotencyKey: "job-charge:job", Description: "charge", Metadata: map[string]any{"x": 1}})
+	if err != nil || got.LedgerID != "ledger-1" || got.BalanceFen != 75 {
+		t.Fatalf("got=%#v err=%v", got, err)
+	}
+}
+
+func TestListBillingPriceRulesUsesExplicitColumns(t *testing.T) {
+	q := &fakeQuerier{}
+	db := NewDatabase(Config{Backend: BackendPostgres}, q)
+	_, err := db.ListBillingPriceRules(context.Background(), false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if q.sql != ListBillingPriceRulesSQL || reflect.DeepEqual(q.args, []any{false}) == false {
+		t.Fatalf("sql=%q args=%#v", q.sql, q.args)
+	}
+}