Golang常用Mock方式总结

1.通用Mock方式

类似Java Mockito。testify和mockery结合使用，testify是一个golang测试框架，主要有assert、mock和test suite三个特性，mockery利用testify的mock来生成mock的代码。

testify包下载： go get github.com/stretchr/testify mockery安装： go get github.com/vektra/mockery/.../

mockery会根据定义的interface生成对应的mock struct。

示例代码

common/etcd/client.go

common/etcd/mocks/EtcdClient.go

sql-driver/rds/config/loader/remote_configuration_loader_test.go

1. 生成mock strcut

命令行执行go generate 或者使用goland直接生成，此处会自动创建mocks目录，以及对应的mock struct文件。

生成的代码如下所示：

// Code generated by mockery v1.0.0. DO NOT EDIT. package mocks import ( etcd "github.com/huaweicloud/devcloud-go/common/etcd" mock "github.com/stretchr/testify/mock" clientv3 "go.etcd.io/etcd/client/v3" ) // EtcdClient is an autogenerated mock type for the EtcdClient type type EtcdClient struct { mock.Mock } // Close provides a mock function with given fields: func (_m *EtcdClient) Close() error { ret := _m.Called() var r0 error if rf, ok := ret.Get(0).(func() error); ok { r0 = rf() } else { r0 = ret.Error(0) } return r0 } // Del provides a mock function with given fields: key func (_m *EtcdClient) Del(key string) (int64, error) { ret := _m.Called(key) var r0 int64 if rf, ok := ret.Get(0).(func(string) int64); ok { r0 = rf(key) } else { r0 = ret.Get(0).(int64) } var r1 error if rf, ok := ret.Get(1).(func(string) error); ok { r1 = rf(key) } else { r1 = ret.Error(1) } return r0, r1 } // Get provides a mock function with given fields: key func (_m *EtcdClient) Get(key string) (string, error) { ret := _m.Called(key) var r0 string if rf, ok := ret.Get(0).(func(string) string); ok { r0 = rf(key) } else { r0 = ret.Get(0).(string) } var r1 error if rf, ok := ret.Get(1).(func(string) error); ok { r1 = rf(key) } else { r1 = ret.Error(1) } return r0, r1 } // List provides a mock function with given fields: prefix func (_m *EtcdClient) List(prefix string) ([]*etcd.KeyValue, error) { ret := _m.Called(prefix) var r0 []*etcd.KeyValue if rf, ok := ret.Get(0).(func(string) []*etcd.KeyValue); ok { r0 = rf(prefix) } else { if ret.Get(0) != nil { r0 = ret.Get(0).([]*etcd.KeyValue) } } var r1 error if rf, ok := ret.Get(1).(func(string) error); ok { r1 = rf(prefix) } else { r1 = ret.Error(1) } return r0, r1 } // Put provides a mock function with given fields: key, value func (_m *EtcdClient) Put(key string, value string) (string, error) { ret := _m.Called(key, value) var r0 string if rf, ok := ret.Get(0).(func(string, string) string); ok { r0 = rf(key, value) } else { r0 = ret.Get(0).(string) } var r1 error if rf, ok := ret.Get(1).(func(string, string) error); ok { r1 = rf(key, value) } else { r1 = ret.Error(1) } return r0, r1 } // Watch provides a mock function with given fields: prefix, startIndex, onEvent func (_m *EtcdClient) Watch(prefix string, startIndex int64, onEvent func(*clientv3.Event)) { _m.Called(prefix, startIndex, onEvent) }

2. 业务代码调用EtcdClient

此处定义了一个RemoteConfigurationLoader，其成员etcdClient的类型为上述定义的EtcdClient interface，在Get方法中调用EtcdClient的Get方法。

type RemoteConfigurationLoader struct { etcdClient etcd.EtcdClient dataSourceKey string routerKey string activeKey string listeners []config.RouterConfigurationListener } func (l *RemoteConfigurationLoader) Get()(string, string, string) { dataSourceConfig, err := l.etcdClient.Get(l.dataSourceKey) if err != nil { return "", "", "" } routerConfig, err := l.etcdClient.Get(l.routerKey) if err != nil { log.Printf("ERROR: get remote routerConfig failed, %v", err) return "", "", "" } active, err := l.etcdClient.Get(l.activeKey) if err != nil { log.Printf("ERROR: get remote active failed, %v", err) return "", "", "" } return dataSourceConfig, routerConfig, active }

3. 测试代码编写

编写对RemoteConfigurationLoader的Get()方法的测试代码，对EtcdClient的Get方法进行mock。

1 import ( 2 "fmt" 3 "testing" 4 5 "github.com/huaweicloud/devcloud-go/common/etcd/mocks" 6 "github.com/stretchr/testify/assert" 7 ) 8 9 func TestRemoteConfigurationLoader_Get(t *testing.T) { 10 mockClient := &mocks.EtcdClient{} 11 loader := &RemoteConfigurationLoader{ 12 dataSourceKey: "datasourceKey", 13 routerKey: "routerKey", 14 activeKey: "activeKey", 15 etcdClient: mockClient, 16 } 17 mockClient.On("Get", loader.dataSourceKey).Return("data", nil).Once() 18 mockClient.On("Get", loader.routerKey).Return("router", nil).Once() 19 mockClient.On("Get", loader.activeKey).Return("active", nil).Once() 20 datasource, router, active := loader.Get() 21 assert.Equal(t, "data", datasource) 22 assert.Equal(t, "router", router) 23 assert.Equal(t, "active", active) 24 }

其中17-19行代码就是在mock我们想要的数据。mockClient调用On方法，首先传入要mock的方法名字，然后传入方法参数，此处是利用golang的反射来实现的。Return方法中传入想要mock的返回数据，最后调用Once()方法表示此方法只执行一次。

4. 参考文档

https://segmentfault.com/a/1190000016897506

https://www.xuanzhangjiong.top/2019/10/12/mockery%E4%BB%8B%E7%BB%8D%E5%8F%8A%E4%BD%BF%E7%94%A8/

https://github.com/vektra/mockery

2. Mysql Mock

2.1 mock mySQL Server(推荐)

利用 github.com/dolthub/go-mysql-server，go-mysql-server基于Mysql语法，解析标准sql，它可以在内存中启动一个mysql server。

安装：

go get github.com/dolthub/go-mysql-server

示例代码：

package main import ( "fmt" "time" sqle "github.com/dolthub/go-mysql-server" "github.com/dolthub/go-mysql-server/auth" "github.com/dolthub/go-mysql-server/memory" "github.com/dolthub/go-mysql-server/server" "github.com/dolthub/go-mysql-server/sql" "github.com/dolthub/go-mysql-server/sql/information_schema" ) const ( user = "user" passwd = "pass" address = "localhost" port = "13306" dbName = "test" tableName = "pets" ) func main() { engine := sqle.NewDefault( sql.NewDatabaseProvider( createTestDatabase(), information_schema.NewInformationSchemaDatabase(), )) config := server.Config{ Protocol: "tcp", Address: fmt.Sprintf("%s:%s", address, port), Auth: auth.NewNativeSingle(user, passwd, auth.AllPermissions), } s, err := server.NewDefaultServer(config, engine) if err != nil { panic(err) } go func() { s.Start() }() fmt.Println("mysql-server started!") <- make(chan interface{}) } func createTestDatabase() *memory.Database { db := memory.NewDatabase(dbName) table := memory.NewTable(tableName, sql.Schema{ {Name: "name", Type: sql.Text, Nullable: false, Source: tableName}, {Name: "email", Type: sql.Text, Nullable: false, Source: tableName}, {Name: "phone_numbers", Type: sql.JSON, Nullable: false, Source: tableName}, {Name: "created_at", Type: sql.Timestamp, Nullable: false, Source: tableName}, }) db.AddTable(tableName, table) ctx := sql.NewEmptyContext() rows := []sql.Row{ sql.NewRow("John Doe", "jasonkay@doe.com", []string{"555-555-555"}, time.Now()), sql.NewRow("John Doe", "johnalt@doe.com", []string{}, time.Now()), sql.NewRow("Jane Doe", "jane@doe.com", []string{}, time.Now()), sql.NewRow("Evil Bob", "jasonkay@gmail.com", []string{"555-666-555", "666-666-666"}, time.Now()), } for _, row := range rows { _ = table.Insert(ctx, row) } return db

2.2 mock sql driver

使用 DATA-DOG/go-sqlmock，该包实现了go sdk sql/driver的接口，本质上是一个mock驱动

安装：

go get github.com/DATA-DOG/go-sqlmock

示例代码

原生sql代码使用 示例代码见：https://github.com/DATA-DOG/go-sqlmock

编写ut时利用定义的globalMock做dml前置操作，具体使用方法见官方文档。

var ( globalOrm orm.Ormer once sync.Once mockOnce sync.Once globalMockOrm orm.Ormer GlobalMock sqlmock.Sqlmock ) func GetOrmer() orm.Ormer { if utils.GetenvOrDefault("isTest", "") == "true" { mockOnce.Do(func() { var db *sql.DB db, GlobalMock, _ = sqlmock.New() GlobalMock.ExpectPrepare("SELECT TIMEDIFF") GlobalMock.ExpectPrepare("SELECT ENGINE") globalMockOrm, _ = orm.NewOrmWithDB("mysql", "default", db) }) return globalMockOrm } once.Do(func() { // override the default value(1000) to return all records when setting no limit orm.DefaultRowsLimit = -1 globalOrm = orm.NewOrm() }) return globalOrm }

测试代码

type Book struct { Id int64 `gorm:"column:id"` Title string `gorm:"column:title"` } func TestSqlMockBeegoOrm(t *testing.T) { os.Setenv("isTest", "true") ormer := driver_test.GetOrmer() GlobalMock.ExpectQuery("SELECT").WillReturnRows( sqlmock.NewRows([]string{"id", "title"}). AddRow(1, "one")) book := &Book{Id:1} err := ormer.Read(book) assert.Nil(t, err) assert.Equal(t, "one", book.Title) }

var ( globalGormDB *gorm.DB globalMockGormDB *gorm.DB globalMock sqlmock.Sqlmock once sync.Once mockOnce sync.Once ) func GetGormDB() *gorm.DB { if utils.GetenvOrDefault("isTest", "") == "true" { mockOnce.Do(func() { var db *sql.DB db, globalMock, _ = sqlmock.New() globalMockGormDB, _ = gorm.Open(mysql.New(mysql.Config{ Conn: db, SkipInitializeWithVersion: true, }), &gorm.Config{}) }) return globalMockGormDB } once.Do(func() { globalGormDB, _ = gorm.Open(mysql.Open("user:pass@tcp(127.0.0.1:3306)/dbname"), &gorm.Config{}) }) return globalGormDB }

测试代码

func TestSqlMockGorm(t *testing.T) { os.Setenv("isTest", "true") gormDB := driver_test.GetGormDB() driver_test.GlobalMock.ExpectQuery(regexp.QuoteMeta("SELECT * FROM `books`")).WillReturnRows( sqlmock.NewRows([]string{"id", "title"}). AddRow(1, "one"). AddRow(2, "two")) var books []Book err := gormDB.Find(&books).Error assert.Nil(t, err) assert.Equal(t, 2, len(books)) assert.Equal(t, int64(1), books[0].Id) assert.Equal(t, "one", books[0].Title) assert.Equal(t, int64(2), books[1].Id) assert.Equal(t, "two", books[1].Title) }

2.3 使用优劣

个人感觉mock mysql server最方便，对代码侵入较少，测试代码也会更少，测试范围会更广。

mock sql driver只适合对业务层mock数据库操作，测试业务代码；当使用复杂sql时，需要将orm的链式操作等转为一个复杂sql语句用于mock，需要编写大量测试代码。

而mock mysql server在此基础上还能测试数据库操作的代码是否正确。

2.4 参考文档

使用纯Go实现的Mysql数据库

https://pkg.go.dev/github.com/dolthub/go-mysql-server#section-readme

https://zhuanlan.zhihu.com/p/249313716

https://github.com/DATA-DOG/go-sqlmock

https://blog.csdn.net/weixin_44294408/article/details/120698482

3. Redis Mock

使用github.com/alicebob/miniredis/v2 ，miniredis可以在内存中启动一个redis server，支持大部分redis命令，具体支持情况见github readme

示例代码：

redis/devspore_client_test.go

import ( "context" "testing" "github.com/alicebob/miniredis/v2" "github.com/go-redis/redis/v8" "github.com/stretchr/testify/assert" ) func TestMockRedis(t *testing.T) { server, _ := miniredis.Run() client := redis.NewClient(&redis.Options{Addr: server.Addr()}) ctx := context.Background() client.Set(ctx, "test", "val", 0) res := client.Get(ctx, "test") assert.Nil(t, res.Err()) assert.Equal(t, "val", res.Val()) server.Close() }

4. Ginkgo测试框架

Ginkgo是一个BDD(Behavior Driven Development)风格的go测试框架，与Gomega配合使用，在需要写大量单测时，特别是需要一些通用代码时，Ginkgo可以使用BeforeEach和AfterEach将每个用例的通用步骤提取出来，会让代码看起来很清爽。

具体使用方法见 https://ke-chain.github.io/ginkgodoc/

示例代码

devcloud-go/sql-driver/mysql/devspore_driver_test.go 使用Ginkgo框架编写driver的CRUD测试代码，结合mock mysql server使用。

import ( "database/sql" "fmt" "testing" "github.com/huaweicloud/devcloud-go/sql-driver/rds/config" "github.com/huaweicloud/devcloud-go/sql-driver/rds/datasource" . "github.com/onsi/ginkgo" . "github.com/onsi/gomega" sqle "github.com/dolthub/go-mysql-server" "github.com/dolthub/go-mysql-server/auth" "github.com/dolthub/go-mysql-server/memory" "github.com/dolthub/go-mysql-server/server" mocksql "github.com/dolthub/go-mysql-server/sql" "github.com/dolthub/go-mysql-server/sql/information_schema" ) func TestGinkgoSuite(t *testing.T) { RegisterFailHandler(Fail) RunSpecs(t, "mysql") } var _ = Describe("CRUD", func() { var ( devsporeDB *sql.DB masterDB *sql.DB err error activeNode *datasource.NodeDataSource ) go startMockServer() BeforeEach(func() { devsporeDB, err = sql.Open("devspore_mysql", "../rds/resources/driver_test_config.yaml") Expect(err).NotTo(HaveOccurred()) activeNode, err = initDB() Expect(err).NotTo(HaveOccurred()) masterDB, err = sql.Open("mysql", activeNode.MasterDataSource.Dsn) Expect(err).NotTo(HaveOccurred()) }) AfterEach(func() { Expect(devsporeDB.Close()).NotTo(HaveOccurred()) Expect(masterDB.Close()).NotTo(HaveOccurred()) }) It("Test Query", func() { var ( val string flag bool ) err = devsporeDB.QueryRow("SELECT val FROM foo WHERE id=?", id1).Scan(&val) Expect(err).NotTo(HaveOccurred()) for _, slave := range activeNode.SlavesDatasource { if slave.Name == val { flag = true } } Expect(flag).To(Equal(true)) }) It("Test Insert", func() { var val string _, err = devsporeDB.Exec(`INSERT INTO foo (id, val) VALUES (?, ?)`, id2, "insert") Expect(err).NotTo(HaveOccurred()) err = masterDB.QueryRow("SELECT val FROM foo WHERE id=?", id2).Scan(&val) Expect(err).NotTo(HaveOccurred()) Expect(val).To(Equal("insert")) }) It("Test Update", func() { var val string _, err = devsporeDB.Exec(`UPDATE foo set val=? where id=?`, "update", id1) Expect(err).NotTo(HaveOccurred()) err = masterDB.QueryRow("SELECT val FROM foo WHERE id=?", id1).Scan(&val) Expect(err).NotTo(HaveOccurred()) Expect(val).To(Equal("update")) }) It("Test Delete", func() { var val string _, err = devsporeDB.Exec(`DELETE FROM foo where id=?`, id1) Expect(err).NotTo(HaveOccurred()) err = masterDB.QueryRow("SELECT val FROM foo WHERE id=?", id1).Scan(&val) Expect(err).To(HaveOccurred()) Expect(err.Error()).To(Equal("sql: no rows in result set")) }) }) const ( user = "root" passwd = "root" address = "localhost" port = "13306" ) func startMockServer() { engine := sqle.NewDefault( mocksql.NewDatabaseProvider( memory.NewDatabase("ds0"), memory.NewDatabase("ds1"), memory.NewDatabase("ds0-slave0"), memory.NewDatabase("ds0-slave1"), memory.NewDatabase("ds1-slave0"), memory.NewDatabase("ds1-slave1"), information_schema.NewInformationSchemaDatabase(), )) config := server.Config{ Protocol: "tcp", Address: fmt.Sprintf("%s:%s", address, port), Auth: auth.NewNativeSingle(user, passwd, auth.AllPermissions), } s, err := server.NewDefaultServer(config, engine) if err != nil { panic(err) } go func() { s.Start() }() fmt.Println("mysql-server started!") }

5. 代码参考

示例代码标有文件路径的均来自devcloud-go项目，具体可看https://github.com/huaweicloud/devcloud-go。本文是在本人开发devcloud-go过程中积累而成，各位看官可以移步devcloud-go项目点个star~

Go MySQL Redis 单元测试

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