已完成用户APP首期功能开发

交付用户端首期页面、配套接口、后台资源及测试文档。用户APP构建、静态分析和三个管理后台构建通过；完整测试仍有2项失败，后端模型注释检查未通过，详见交付记录。

backend/api/internal/logic/client/user/checkout_test.go

@@ -0,0 +1,81 @@
+// 功能描述：验证结算金额确认、溢出回滚及已有订单的幂等恢复。
+// 版本：1.0.0。
+package user
+
+import (
+	"fmt"
+	"math"
+	"strings"
+	"testing"
+
+	"git.apinb.com/heqiapp/platforms/backend/api/internal/models"
+	"github.com/DATA-DOG/go-sqlmock"
+)
+
+func TestCheckoutMoneyAndRollback(t *testing.T) {
+	for _, tc := range []struct {
+		name            string
+		price, expected int64
+		code            int
+	}{
+		{"数量按服务端价格结算", 12800, 25600, 0},
+		{"价格变化回滚库存", 12800, 12800, 2401},
+		{"金额溢出不扣库存", math.MaxInt64, 0, 1711},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			mock := primaryTestDB(t)
+			expectAddressAccount(mock)
+			mock.ExpectQuery(`SELECT .* FROM "ec_order"`).WillReturnRows(sqlmock.NewRows([]string{"id"}))
+			mock.ExpectQuery(`SELECT .* FROM "user_address"`).WillReturnRows(sqlmock.NewRows([]string{"id", "identity", "address"}).AddRow(2, "owned", "测试地址"))
+			mock.ExpectBegin()
+			mock.ExpectQuery(`SELECT .* FROM "ec_product".*FOR UPDATE`).WillReturnRows(sqlmock.NewRows([]string{"id", "identity", "price_amount", "stock_quantity"}).AddRow(3, "product", tc.price, 20))
+			if tc.code != 1711 {
+				mock.ExpectExec(`UPDATE "ec_product" SET "stock_quantity"`).WillReturnResult(sqlmock.NewResult(0, 1))
+				mock.ExpectQuery(`SELECT .* FROM "ec_product_image"`).
+					WillReturnRows(sqlmock.NewRows([]string{"id", "image_uri"}).AddRow(8, "/uploads/products/cover.png"))
+			}
+			if tc.code == 0 {
+				mock.ExpectQuery(`INSERT INTO "ec_order"`).WillReturnRows(sqlmock.NewRows([]string{"id"}).AddRow(5))
+				mock.ExpectQuery(`INSERT INTO "ec_order_item"`).WillReturnRows(sqlmock.NewRows([]string{"id"}).AddRow(6))
+				mock.ExpectCommit()
+			} else {
+				mock.ExpectRollback()
+				mock.ExpectQuery(`SELECT .* FROM "ec_order"`).WillReturnRows(sqlmock.NewRows([]string{"id"}))
+			}
+			ctx, response := addressContext(fmt.Sprintf(`{"request_no":"order-request","address_identity":"owned","contact_name":"收货人","contact_phone":"13800000001","expected_payable_amount":%d,"items":[{"product_identity":"product","quantity":2}]}`, tc.expected), "")
+			CreateShopOrder(ctx)
+			if !strings.Contains(response.Body.String(), fmt.Sprintf(`"code":%d`, tc.code)) {
+				t.Fatal(response.Body.String())
+			}
+			if tc.code == 0 && !strings.Contains(response.Body.String(), `"payable_amount":25600`) {
+				t.Fatal("未按数量返回总额")
+			}
+			if err := mock.ExpectationsWereMet(); err != nil {
+				t.Fatal(err)
+			}
+		})
+	}
+}
+
+func TestShopOrderProductSnapshotIncludesCover(t *testing.T) {
+	value := shopOrderProductSnapshot(models.EcProduct{Entity: models.Entity{Identity: "product"}, Name: "报警器", ProductCode: "BJQ-01"}, "/uploads/products/cover.png")
+	for _, expected := range []string{`"identity":"product"`, `"name":"报警器"`, `"product_code":"BJQ-01"`, `"image_url":"/uploads/products/cover.png"`} {
+		if !strings.Contains(value, expected) {
+			t.Fatalf("订单商品快照缺少 %s: %s", expected, value)
+		}
+	}
+}
+
+func TestCheckoutRetrySurvivesAddressRemoval(t *testing.T) {
+	mock := primaryTestDB(t)
+	expectAddressAccount(mock)
+	mock.ExpectQuery(`SELECT .* FROM "ec_order".*request_no = \$1 AND user_account_id = \$2`).WillReturnRows(sqlmock.NewRows([]string{"id", "identity", "payable_amount"}).AddRow(5, "existing-order", 25600))
+	ctx, response := addressContext(`{"request_no":"order-request","address_identity":"removed","contact_name":"收货人","contact_phone":"13800000001","items":[{"product_identity":"product","quantity":2}]}`, "")
+	CreateShopOrder(ctx)
+	if !strings.Contains(response.Body.String(), `"identity":"existing-order"`) {
+		t.Fatal(response.Body.String())
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatal(err)
+	}
+}