转到这里,使用 gorm到或/映射到数据库(PSQL)。
我有以下代码:
package dbstuff
import (
"errors"
"github.com/google/uuid"
"github.com/jinzhu/gorm"
_ "github.com/jinzhu/gorm/dialects/postgres"
)
type OrderPersister struct {
db *gorm.DB
}
func (p *OrderPersister) GetOrder(id uuid.UUID) (*Order, error) {
ret := &Order{}
err := p.db.Table("orders").Where("order_id = ?", id).Scan(ret).Error
return ret, err
}
我正在尝试为它编写一个单元测试,如下所示:package dbstuff
import (
"testing"
"errors"
"github.com/stretchr/testify/assert"
)
func TestErrInternalServerError(t *testing.T) {
// given
id := uuid.New()
op := OrderPersister{}
// when
order, err := op.GetOrder(id)
// then
assert.NotNil(t, order)
assert.NotNil(t, err)
}
当我运行它时,我得到无效的内存地址或 nil 指针取消引用错误,因为我没有实例化设置 *gorm.DB
在我的 OrderPersister
实例。有没有一种简单的方法来模拟/ stub ,以便我的测试确认我们尝试查询 orders
表并返回或/映射的结果?
最佳答案
我将使用 testify包为您的代码编写单元测试。而不是使用具体类型 *gorm.DB
,声明 OrderPersister
的 DB 接口(interface)结构。由于我们不能在 Go 中模拟具体类型及其方法。我们需要创建一个抽象层 - interface
.63622995/db/db.go
:
package db
type OrmDBWithError struct {
OrmDB
Error error
}
type OrmDB interface {
Table(name string) OrmDB
Where(query interface{}, args ...interface{}) OrmDB
Scan(dest interface{}) *OrmDBWithError
}
63622995/main.go
:package main
import (
"github.com/google/uuid"
_ "github.com/jinzhu/gorm/dialects/postgres"
"github.com/mrdulin/golang/src/stackoverflow/63622995/db"
)
type Order struct {
order_id string
}
type OrderPersister struct {
DB db.OrmDB
//DB *gorm.DB
}
func (p *OrderPersister) GetOrder(id uuid.UUID) (*Order, error) {
ret := &Order{}
err := p.DB.Table("orders").Where("order_id = ?", id).Scan(ret).Error
return ret, err
}
为实现 OrmDB
的 db 创建了模拟对象界面。然后,您可以创建此模拟 DB 对象并将其传递给 OrderPersister
结构。63622995/mocks/db.go
:package mocks
import (
"github.com/mrdulin/golang/src/stackoverflow/63622995/db"
"github.com/stretchr/testify/mock"
)
type MockedOrmDB struct {
mock.Mock
}
func (s *MockedOrmDB) Table(name string) db.OrmDB {
args := s.Called(name)
return args.Get(0).(db.OrmDB)
}
func (s *MockedOrmDB) Where(query interface{}, args ...interface{}) db.OrmDB {
arguments := s.Called(query, args)
return arguments.Get(0).(db.OrmDB)
}
func (s *MockedOrmDB) Scan(dest interface{}) *db.OrmDBWithError {
args := s.Called(dest)
return args.Get(0).(*db.OrmDBWithError)
}
63622995/main_test.go
:package main
import (
"testing"
"github.com/google/uuid"
"github.com/mrdulin/golang/src/stackoverflow/63622995/db"
"github.com/mrdulin/golang/src/stackoverflow/63622995/mocks"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/mock"
)
func TestOrderPersister_GetOrder(t *testing.T) {
assert := assert.New(t)
t.Run("should get order", func(t *testing.T) {
testDb := new(mocks.MockedOrmDB)
id := uuid.New()
testDb.
On("Table", "orders").
Return(testDb).
On("Where", "order_id = ?", mock.Anything).
Return(testDb).
On("Scan", mock.Anything).Run(func(args mock.Arguments) {
ret := args.Get(0).(*Order)
ret.order_id = "123"
}).
Return(&db.OrmDBWithError{Error: nil})
op := OrderPersister{DB: testDb}
got, err := op.GetOrder(id)
testDb.AssertExpectations(t)
assert.Nil(err)
assert.Equal(Order{order_id: "123"}, *got)
})
t.Run("should return error", func(t *testing.T) {
testDb := new(mocks.MockedOrmDB)
id := uuid.New()
testDb.
On("Table", "orders").
Return(testDb).
On("Where", "order_id = ?", mock.Anything).
Return(testDb).
On("Scan", mock.Anything).
Return(&db.OrmDBWithError{Error: errors.New("network")})
op := OrderPersister{DB: testDb}
got, err := op.GetOrder(id)
testDb.AssertExpectations(t)
assert.Equal(Order{}, *got)
assert.Equal(err.Error(), "network")
})
}
单元测试结果:=== RUN TestOrderPersister_GetOrder
=== RUN TestOrderPersister_GetOrder/should_get_order
TestOrderPersister_GetOrder/should_get_order: main_test.go:32: PASS: Table(string)
TestOrderPersister_GetOrder/should_get_order: main_test.go:32: PASS: Where(string,string)
TestOrderPersister_GetOrder/should_get_order: main_test.go:32: PASS: Scan(string)
=== RUN TestOrderPersister_GetOrder/should_return_error
TestOrderPersister_GetOrder/should_return_error: main_test.go:49: PASS: Table(string)
TestOrderPersister_GetOrder/should_return_error: main_test.go:49: PASS: Where(string,string)
TestOrderPersister_GetOrder/should_return_error: main_test.go:49: PASS: Scan(string)
--- PASS: TestOrderPersister_GetOrder (0.00s)
--- PASS: TestOrderPersister_GetOrder/should_get_order (0.00s)
--- PASS: TestOrderPersister_GetOrder/should_return_error (0.00s)
PASS
Process finished with exit code 0
覆盖报告:关于unit-testing - 如何使用 gomock (或类似的)来模拟/验证对数据库的调用?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/63622995/