pay/internal/provider/alipay/alipay_refund_test.go

package alipay_test

import (
	"context"
	"crypto"
	"crypto/rand"
	"crypto/rsa"
	"crypto/sha256"
	"crypto/x509"
	"encoding/base64"
	"encoding/json"
	"errors"
	"net/http"
	"net/http/httptest"
	"testing"

	sw "github.com/smartwalle/alipay/v3"

	"github.com/wangjia/pay/internal/money"
	"github.com/wangjia/pay/internal/provider"
	ali "github.com/wangjia/pay/internal/provider/alipay"
)

// fakeAlipayRefund 返回一份用"支付宝侧"私钥签名的 alipay.trade.refund 响应。
func fakeAlipayRefund(t *testing.T, aliPriv *rsa.PrivateKey, fundChange string) *httptest.Server {
	t.Helper()
	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		node := map[string]any{
			"code": "10000", "msg": "Success",
			"trade_no": "2021AAA", "out_trade_no": "PAY-1",
			"refund_fee": "199.00", "fund_change": fundChange,
		}
		nodeJSON, _ := json.Marshal(node)
		// 支付宝对 response node 的原文做 RSA2 签名(sign_type=RSA2)。
		h := sha256.Sum256(nodeJSON)
		sig, _ := rsa.SignPKCS1v15(rand.Reader, aliPriv, crypto.SHA256, h[:])
		resp := map[string]any{
			"alipay_trade_refund_response": json.RawMessage(nodeJSON),
			"sign":                         base64.StdEncoding.EncodeToString(sig),
		}
		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(resp)
	}))
}

// buildRefundClient 与 alipay_test.go 的 genKeys/buildClient 同一套约定:
//
// ⚠️ 与 brief 草稿的差异(执行时发现,已按 SDK 实际要求修正,和 alipay_test.go 注释一致):
//  1. LoadAliPayPublicKey 内部走 PKIX(SubjectPublicKeyInfo)解码,不是 PKCS1 ——
//     用 x509.MarshalPKIXPublicKey 而非 MarshalPKCS1PublicKey。
//  2. smartwalle v3.2.29 没有 sw.WithGateway 这个 option;设置网关的是
//     WithSandboxGateway(gateway)/WithProductionGateway(gateway)。client 用
//     production=false 建(沙箱),对应用 WithSandboxGateway 把 host 指到 httptest。
func buildRefundClient(t *testing.T, gateway string, aliPub *rsa.PublicKey) *sw.Client {
	t.Helper()
	app, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		t.Fatalf("gen app key: %v", err)
	}
	c, err := sw.New(
		"2021000000000000",
		base64.StdEncoding.EncodeToString(x509.MarshalPKCS1PrivateKey(app)),
		false,
		sw.WithSandboxGateway(gateway),
	)
	if err != nil {
		t.Fatalf("new client: %v", err)
	}
	aliPubDER, err := x509.MarshalPKIXPublicKey(aliPub)
	if err != nil {
		t.Fatalf("marshal ali pub: %v", err)
	}
	if err := c.LoadAliPayPublicKey(base64.StdEncoding.EncodeToString(aliPubDER)); err != nil {
		t.Fatalf("load pub: %v", err)
	}
	return c
}

func TestAlipayRefundSyncSuccess(t *testing.T) {
	aliKey, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		t.Fatalf("gen ali key: %v", err)
	}
	ts := fakeAlipayRefund(t, aliKey, "Y")
	defer ts.Close()
	p := ali.New(buildRefundClient(t, ts.URL, &aliKey.PublicKey))

	if !p.Capabilities().SupportsRefund {
		t.Fatal("alipay Capabilities.SupportsRefund 应为 true")
	}
	ref, status, err := p.Refund(context.Background(), "PAY-1", "rf-123", 19900, "用户申请")
	if err != nil {
		t.Fatalf("refund: %v", err)
	}
	if status != provider.PaidSucceeded || ref != "rf-123" {
		t.Fatalf("refund result: ref=%s status=%s", ref, status)
	}
}

// FundChange=N 表示重复退款(同 out_request_no 幂等命中,支付宝侧未再发生资金变化)——
// 仍是"受理成功",不能当失败处理,否则重试路径会把已完成的退款误判为失败。
func TestAlipayRefundIdempotentNoFundChange(t *testing.T) {
	aliKey, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		t.Fatalf("gen ali key: %v", err)
	}
	ts := fakeAlipayRefund(t, aliKey, "N")
	defer ts.Close()
	p := ali.New(buildRefundClient(t, ts.URL, &aliKey.PublicKey))

	ref, status, err := p.Refund(context.Background(), "PAY-1", "rf-123", 19900, "用户申请")
	if err != nil {
		t.Fatalf("refund: %v", err)
	}
	if status != provider.PaidSucceeded || ref != "rf-123" {
		t.Fatalf("refund result: ref=%s status=%s", ref, status)
	}
}

// 渠道拒绝(如金额超出可退余额)返回 code!=10000 的失败响应 —— TradeRefund 应把
// rsp.Error 包出去,refundRef 留空,状态归 PaidFailed。
// TestAlipayRefundChannelRejected 的响应必须像 fakeAlipayRefund 一样用"支付宝侧"私钥
// 签名——否则 DecodeNotification/TradeRefund 在验签阶段就报错,走的是传输错误分支
// (rsp 根本拿不到),永远到不了下面要验证的 rsp.IsFailure() 分支,原始 fixture 未签名
// 这个测试其实是假绿的(见 P4 item 2)。
func TestAlipayRefundChannelRejected(t *testing.T) {
	aliKey, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		t.Fatalf("gen ali key: %v", err)
	}
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		node := map[string]any{
			"code": "40004", "msg": "Business Failed",
			"sub_code": "ACQ.TRADE_HAS_FINISHED", "sub_msg": "交易已完结",
		}
		nodeJSON, _ := json.Marshal(node)
		h := sha256.Sum256(nodeJSON)
		sig, _ := rsa.SignPKCS1v15(rand.Reader, aliKey, crypto.SHA256, h[:])
		resp := map[string]any{
			"alipay_trade_refund_response": json.RawMessage(nodeJSON),
			"sign":                         base64.StdEncoding.EncodeToString(sig),
		}
		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(resp)
	}))
	defer ts.Close()
	p := ali.New(buildRefundClient(t, ts.URL, &aliKey.PublicKey))

	ref, status, err := p.Refund(context.Background(), "PAY-1", "rf-123", 19900, "用户申请")
	if err == nil {
		t.Fatal("want 渠道拒绝返回 error")
	}
	// 真正走到 rsp.IsFailure() 分支后,error 须满足 errors.Is(..., ErrRefundRejected)——
	// 与 item 1 配套:gateway.Refund 靠这个哨兵区分"渠道确定性拒绝"(可标 failed)
	// vs"结果不确定"(须留 processing)。
	if !errors.Is(err, provider.ErrRefundRejected) {
		t.Fatalf("err = %v want wrap ErrRefundRejected", err)
	}
	if status != provider.PaidFailed || ref != "" {
		t.Fatalf("refund result: ref=%q status=%s", ref, status)
	}
}

// TestMoneyFormatStripsTrailingZerosForAlipay 记录一个既定行为(防静默回归):
// money.Format 对整元金额去尾零,19900 分(199.00 元)格式化成 "199" 而非 "199.00"。
// 上面所有 alipay refund 用例传的 19900 分走的正是这条路径(见 p.Refund 内
// money.Format(amountMinor,"CNY") 再作为 RefundAmount 传给 alipay.trade.refund)。
// 支付宝接受这种去尾零形态的金额字符串,且与建单路径(Create → money.Format)同源、
// 已被 TestParseFormatRoundTrip 覆盖一致性,这里单独钉一行防止 alipay refund 路径
// 依赖的具体字符串形态被静默改掉。
func TestMoneyFormatStripsTrailingZerosForAlipay(t *testing.T) {
	got, err := money.Format(19900, "CNY")
	if err != nil {
		t.Fatalf("money.Format(19900,CNY): %v", err)
	}
	if got != "199" {
		t.Fatalf("money.Format(19900,CNY) = %q want %q(既定去尾零行为)", got, "199")
	}
}