Go Mock 接口测试单元测试极简教程

一个会写诗的程序员

发布于 2022-05-30 09:19:42

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发布于 2022-05-30 09:19:42

文章被收录于专栏：一个会写诗的程序员的博客

gomock 是 Google 开源的 Golang 测试框架。

GoMock is a mocking framework for the Go programming language. https://github.com/golang/mock

快速开始

安装 mockgen

To get the latest released version use: Go version < 1.16

GO111MODULE=on go get github.com/golang/mock/mockgen@v1.6.0

Go 1.16+

go install github.com/golang/mock/mockgen@v1.6.0

定义好被测接口

// mockgen -source=./driver/navigator_driver.go -destination ./driver/navigator_driver_mock.go -package driver

type INavigatorDriver interface {
    Query(Ctx context.Context,
        SqlClient *sqlclient.SQLClient,
        sqlKey,
        sql string,
        searchOptions ...*engine.Option,
    ) ([]map[string]interface{}, error)

    BatchGetProductInfoMap(Ctx context.Context,
        SqlClient *sqlclient.SQLClient,
        date string,
        ids []int64,
        entityFields []string,
    ) (map[int64]interface{}, error)

    BatchGetBrandInfoMap(Ctx context.Context,
        SqlClient *sqlclient.SQLClient,
        date string,
        ids []int64,
        entityFields []string,
    ) (map[int64]interface{}, error)
}

type NavigatorDriver struct {
}

使用 mockgen 命令行自动生成 gomock代码

gomock通过mockgen命令生成包含mock对象的.go文件，其生成的mock对象具备mock+stub的强大功能.

mockgen -source=./driver/navigator_driver.go -destination ./driver/navigator_driver_mock.go -package driver

其中, navigator_driver_mock.go 是生成的 mock 代码.

代码目录:

类型关系:

生成的Mock Stub代码如下:

// Code generated by MockGen. DO NOT EDIT.
// Source: ./driver/navigator_driver.go

// Package driver is a generated GoMock package.
package driver

import (
    context "context"
    reflect "reflect"

    ...
    gomock "github.com/golang/mock/gomock"
)

// MockINavigatorDriver is a mock of INavigatorDriver interface.
type MockINavigatorDriver struct {
    ctrl     *gomock.Controller
    recorder *MockINavigatorDriverMockRecorder
}

// MockINavigatorDriverMockRecorder is the mock recorder for MockINavigatorDriver.
type MockINavigatorDriverMockRecorder struct {
    mock *MockINavigatorDriver
}

// NewMockINavigatorDriver creates a new mock instance.
func NewMockINavigatorDriver(ctrl *gomock.Controller) *MockINavigatorDriver {
    mock := &MockINavigatorDriver{ctrl: ctrl}
    mock.recorder = &MockINavigatorDriverMockRecorder{mock}
    return mock
}

// EXPECT returns an object that allows the caller to indicate expected use.
func (m *MockINavigatorDriver) EXPECT() *MockINavigatorDriverMockRecorder {
    return m.recorder
}

// BatchGetBrandInfoList mocks base method.
func (m *MockINavigatorDriver) BatchGetBrandInfoMap(Ctx context.Context, SqlClient *sqlclient.SQLClient, date string, ids []int64, entityFields []string) (map[int64]interface{}, error) {
    m.ctrl.T.Helper()
    ret := m.ctrl.Call(m, "BatchGetBrandInfoMap", Ctx, SqlClient, date, ids, entityFields)
    ret0, _ := ret[0].(map[int64]interface{})
    ret1, _ := ret[1].(error)
    return ret0, ret1
}

// BatchGetBrandInfoList indicates an expected call of BatchGetBrandInfoList.
func (mr *MockINavigatorDriverMockRecorder) BatchGetBrandInfoList(Ctx, SqlClient, date, ids, entityFields interface{}) *gomock.Call {
    mr.mock.ctrl.T.Helper()
    return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "BatchGetBrandInfoMap", reflect.TypeOf((*MockINavigatorDriver)(nil).BatchGetBrandInfoMap), Ctx, SqlClient, date, ids, entityFields)
}

// BatchGetProductInfoList mocks base method.
func (m *MockINavigatorDriver) BatchGetProductInfoMap(Ctx context.Context, SqlClient *sqlclient.SQLClient, date string, ids []int64, entityFields []string) (map[int64]interface{}, error) {
    m.ctrl.T.Helper()
    ret := m.ctrl.Call(m, "BatchGetProductInfoMap", Ctx, SqlClient, date, ids, entityFields)
    ret0, _ := ret[0].(map[int64]interface{})
    ret1, _ := ret[1].(error)
    return ret0, ret1
}

// BatchGetProductInfoList indicates an expected call of BatchGetProductInfoList.
func (mr *MockINavigatorDriverMockRecorder) BatchGetProductInfoList(Ctx, SqlClient, date, ids, entityFields interface{}) *gomock.Call {
    mr.mock.ctrl.T.Helper()
    return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "BatchGetProductInfoMap", reflect.TypeOf((*MockINavigatorDriver)(nil).BatchGetProductInfoMap), Ctx, SqlClient, date, ids, entityFields)
}

// Query mocks base method.
func (m *MockINavigatorDriver) Query(Ctx context.Context, SqlClient *sqlclient.SQLClient, sqlKey, sql string, searchOptions ...*engine.Option) ([]map[string]interface{}, error) {
    m.ctrl.T.Helper()
    varargs := []interface{}{Ctx, SqlClient, sqlKey, sql}
    for _, a := range searchOptions {
        varargs = append(varargs, a)
    }
    ret := m.ctrl.Call(m, "Query", varargs...)
    ret0, _ := ret[0].([]map[string]interface{})
    ret1, _ := ret[1].(error)
    return ret0, ret1
}

// Query indicates an expected call of Query.
func (mr *MockINavigatorDriverMockRecorder) Query(Ctx, SqlClient, sqlKey, sql interface{}, searchOptions ...interface{}) *gomock.Call {
    mr.mock.ctrl.T.Helper()
    varargs := append([]interface{}{Ctx, SqlClient, sqlKey, sql}, searchOptions...)
    return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Query", reflect.TypeOf((*MockINavigatorDriver)(nil).Query), varargs...)
}

测试代码实例

我们来 Mock 如下代码中的这个接口调用的返回值:

datasourceData, _ := navigatorDriver.Query(u.Ctx, u.Datasource.SqlClient, u.Datasource.SqlKey, navigatorSQL)

func (u *UIComponent) RenderDataTable() ([]map[string]interface{}, error) {
    bu, _ := json.Marshal(u)
    fmt.Println(string(bu))
    endTime := u.DateRangeFilter.EndDate
    dateType := u.DateRangeFilter.DaysType
    // 本周期时间
    dateStr := indexu.GetDateStr(endTime)

    // 1.fetch 数据源
    // 1.1 select 数据源字段 select columns
    columnNames := make([]string, 0)
    for _, e := range u.Datasource.Columns {
        columnNames = append(columnNames, e.Name)
    }

    // 1.2 数据源表
    datasourceTable := u.Datasource.TableName

    // 1.3 过滤条件 DateRangeFilter 是固定的
    whereExpr := buildWhereExpr(dateStr, dateType, u)
    datasourceCQL := alpha.NewCQL().SELECT(columnNames...).FROM(datasourceTable).WHERE(whereExpr).ORDERBY2(u.Datasource.DSOrderType, u.Datasource.DSOrderColumn).LIMIT2(u.Datasource.DSLimit)

    // 1.4 从数据源获取数据(领航者)
    // TODO MOCK, 线上用真实的 NavigatorQueryList 查询
    navigatorDriver := u.INavigatorDriver
    navigatorSQL := datasourceCQL.Compile()
    logu.CtxInfo(u.Ctx, "RenderDataTable", "navigatorSQL: %v", navigatorSQL)
    datasourceData, _ := navigatorDriver.Query(u.Ctx, u.Datasource.SqlClient, u.Datasource.SqlKey, navigatorSQL)
    // 1.5 RSD 数据中添加排名字段信息 RankKey
    if u.NeedRank {
        datasourceData = rocket.NewRSD2(datasourceData, u.Ctx, u.Datasource.SqlClient, u.INavigatorDriver).WithRank(u.RankKey, u.Datasource.Columns).Records
    }

    // 2.内存指标计算
    sqlite, _ := driver.InitSqlite(u.Ctx, map[string]interface{}{})

    // 2.1 从数据源返回数据中解析出列的元数据信息
    columns := ParseColumnsMeta(datasourceData)
    fmt.Println(columns)

    // 2.2 表名生成
    sqliteTableName := driver.GenerateUniqSQLiteTableName()

    // 2.3 建内存表
    driver.CreateTable(u.Ctx, sqliteTableName, columns, sqlite)
    // 2.4 同步数据到内存
    driver.InsertData(u.Ctx, sqliteTableName, datasourceData, columns, sqlite)

    // 2.5 内存数据条数校验
    count, _, _ := driver.Query(nil, fmt.Sprintf("select count(1) as count from %s", sqliteTableName), sqlite)

    if nums, err := convert.ToInt64E(count[0]["count"]); err == nil && nums <= 0 {
        return nil, fmt.Errorf("datasource empty")
    }

    // 2.6 内存计算非指标列
    var selectItem = []string{}
    for _, c := range u.Datasource.Columns { // 指标计算规则元数据信息
        if !c.IsDataIndex {
            cname := c.Name
            selectItem = append(selectItem, cname)
        }
    }
    // 2.7 内存计算指标列
    indexColumns := getIndexColumns(u.Datasource.Columns)
    // add incr select items
    for _, column := range indexColumns {
        columnName := column.Name
        var exp = fmt.Sprintf("IndexInfo(%s) as %s", columnName, columnName)
        selectItem = append(selectItem, exp)
    }

    // 2.8 CQL中添加排名信息 UDF
    if u.NeedRank {
        // Rank Key 是单独指定的,不是数据列的概念
        rankKey := u.RankKey
        selectItem = append(selectItem, fmt.Sprintf("RankInfo(%s) as %s", rankKey, rankKey))
    }

    memCQL := alpha.NewCQL().
        SELECT(selectItem...).
        FROM(sqliteTableName)

    if u.DFLimit != nil && u.DFOffset != nil {
        memCQL = memCQL.LIMIT3(*u.DFLimit, *u.DFOffset)
    } else if u.DFLimit != nil && u.DFOffset == nil {
        memCQL = memCQL.LIMIT2(*u.DFLimit)
    }

    incrSQL := memCQL.Compile()
    fmt.Println(incrSQL)

    result, _, _ := driver.Query(u.Ctx, incrSQL, sqlite)

    rsd := rocket.NewRSD2(result, u.Ctx, u.Datasource.SqlClient, u.INavigatorDriver).
        UnmarshalIndexInfo(u.Datasource.Columns).
        UnmarshalRankInfo(u.NeedRank, u.RankKey).
        FillEntityInfoColumn(dateStr, u.Datasource.Columns)

    return rsd.Records, nil
}

接口定义

// mockgen -source=./driver/navigator_driver.go -destination ./driver/navigator_driver_mock.go -package driver

type INavigatorDriver interface {
    Query(Ctx context.Context,
        SqlClient *sqlclient.SQLClient,
        sqlKey,
        sql string,
        searchOptions ...*engine.Option,
    ) ([]map[string]interface{}, error)

    BatchGetProductInfoMap(Ctx context.Context,
        SqlClient *sqlclient.SQLClient,
        date string,
        ids []int64,
        entityFields []string,
    ) (map[int64]interface{}, error)

    BatchGetBrandInfoMap(Ctx context.Context,
        SqlClient *sqlclient.SQLClient,
        date string,
        ids []int64,
        entityFields []string,
    ) (map[int64]interface{}, error)
}

type NavigatorDriver struct {
}

mock 测试代码

关键代码行:

    ctrl := gomock.NewController(t)
    defer ctrl.Finish()

    mockDriver := driver.NewMockINavigatorDriver(ctrl)
    // NavigatorQueryList 期望返回
    mockDriver.
        EXPECT().
        Query(ctx, SqlClient, "compass_strategy_chance_property_product_stats_di", gomock.Any(), gomock.Any()).
        Return(driver.MockNavigatorQueryListProductStats())

完整代码:

var (
    ctx       = context.Background()
    SqlClient = gomock.Any()
)

func TestDataTableUIComponent(t *testing.T) {
    ctrl := gomock.NewController(t)
    defer ctrl.Finish()

    mockDriver := driver.NewMockINavigatorDriver(ctrl)
    // NavigatorQueryList 期望返回
    mockDriver.
        EXPECT().
        Query(ctx, SqlClient, "compass_strategy_chance_property_product_stats_di", gomock.Any(), gomock.Any()).
        Return(driver.MockNavigatorQueryListProductStats())

    mockDriver.
        EXPECT().
        BatchGetProductInfoList(ctx, SqlClient, gomock.Any(), gomock.Any(), gomock.Any()).
        Return(driver.MockNavigatorQueryListProudctMap())

    //mockDriver.
    //  EXPECT().
    //  BatchGetBrandInfoList(ctx, SqlClient, gomock.Any(), gomock.Any(), gomock.Any()).
    //  Return(driver.MockNavigatorQueryListBrandMap())

    // 初始化数据源
    columns := []datasource.Column{
        {Name: "date"},
        {Name: "days_type"},
        {Name: "stats_date"},
        {Name: "cate_id"},
        {Name: "cate_name"},
        {Name: "property_name"},
        {Name: "market_name"},
        {Name: "product_property_value"},
        {Name: "product_id", IsRowKey: true, NeedFillEntityInfo: true, EntityType: datasource.Product, EntityInfoColumnKey: "product_info"},
        {Name: "pay_amt", IsDataIndex: true},
        {Name: "pay_combo_cnt", IsDataIndex: true},
    }

    datasoure := &datasource.DataSource{
        TableName:     "compass_strategy_chance_property_product_stats_di",
        Columns:       columns,
        SqlKey:        "compass_strategy_chance_property_product_stats_di",
        SearchOptions: []*engine.Option{},
        DSOrderColumn: "pay_combo_cnt",
        DSOrderType:   alpha.DESC,
        DSLimit:       50,
    }

    // 创建组件
    UIComponent := NewUIComponent(
        ctx,
        mockDriver,
        DataTable,
        datasoure,
        &DateRangeFilter{
            DaysType:  constu.DateType_LAST_SEVEN_DAYS,
            StartDate: 0,
            EndDate:   1653177600,
        },
        &DimFilter{
            DimCondition: map[string]string{"cate_id": "123",
                "market_name":            "碎花",
                "product_property_value": "长款裙子",
            },
        },
    )

    // 内存分页
    PageNo := int64(2)
    PageSize := int64(5)

    dflimit := (PageNo - 1) * PageSize
    dfoffset := PageSize

    UIComponent.DFOrderColumn = "pay_combo_cnt"
    UIComponent.DFOrderType = alpha.DESC
    UIComponent.DFLimit = &dflimit
    UIComponent.DFOffset = &dfoffset
    UIComponent.NeedRank = true
    UIComponent.RankKey = "rank"

    // UIComponent 唯一 Render() 数据函数
    result, _ := UIComponent.Render()

    fmt.Println("size:", len(result))

    fmt.Println("====================================================================================")
    b, _ := json.Marshal(result)
    fmt.Println(string(b))
}

gomock

gomock is a mocking framework for the Go programming language. It integrates well with Go's built-in testing package, but can be used in other contexts too.

Installation

Once you have installed Go, install the mockgen tool.

Note: If you have not done so already be sure to add $GOPATH/bin to your PATH.

To get the latest released version use:

Go version < 1.16

GO111MODULE=on go get github.com/golang/mock/mockgen@v1.6.0

Go 1.16+

go install github.com/golang/mock/mockgen@v1.6.0

If you use mockgen in your CI pipeline, it may be more appropriate to fixate on a specific mockgen version. You should try to keep the library in sync with the version of mockgen used to generate your mocks.

Running mockgen

mockgen has two modes of operation: source and reflect.

Source mode

Source mode generates mock interfaces from a source file. It is enabled by using the -source flag. Other flags that may be useful in this mode are -imports and -aux_files.

Example:

mockgen -source=foo.go [other options]

Reflect mode

Reflect mode generates mock interfaces by building a program that uses reflection to understand interfaces. It is enabled by passing two non-flag arguments: an import path, and a comma-separated list of symbols.

You can use "." to refer to the current path's package.

Example:

mockgen database/sql/driver Conn,Driver

# Convenient for `go:generate`.
mockgen . Conn,Driver

Flags

The mockgen command is used to generate source code for a mock class given a Go source file containing interfaces to be mocked. It supports the following flags:

-source: A file containing interfaces to be mocked.
-destination: A file to which to write the resulting source code. If you don't set this, the code is printed to standard output.
-package: The package to use for the resulting mock class source code. If you don't set this, the package name is mock_ concatenated with the package of the input file.
-imports: A list of explicit imports that should be used in the resulting source code, specified as a comma-separated list of elements of the form foo=bar/baz, where bar/baz is the package being imported and foo is the identifier to use for the package in the generated source code.
-aux_files: A list of additional files that should be consulted to resolve e.g. embedded interfaces defined in a different file. This is specified as a comma-separated list of elements of the form foo=bar/baz.go, where bar/baz.go is the source file and foo is the package name of that file used by the -source file.
-build_flags: (reflect mode only) Flags passed verbatim to go build.
-mock_names: A list of custom names for generated mocks. This is specified as a comma-separated list of elements of the form Repository=MockSensorRepository,Endpoint=MockSensorEndpoint, where Repository is the interface name and MockSensorRepository is the desired mock name (mock factory method and mock recorder will be named after the mock). If one of the interfaces has no custom name specified, then default naming convention will be used.
-self_package: The full package import path for the generated code. The purpose of this flag is to prevent import cycles in the generated code by trying to include its own package. This can happen if the mock's package is set to one of its inputs (usually the main one) and the output is stdio so mockgen cannot detect the final output package. Setting this flag will then tell mockgen which import to exclude.
-copyright_file: Copyright file used to add copyright header to the resulting source code.
-debug_parser: Print out parser results only.
-exec_only: (reflect mode) If set, execute this reflection program.
-prog_only: (reflect mode) Only generate the reflection program; write it to stdout and exit.
-write_package_comment: Writes package documentation comment (godoc) if true. (default true)

For an example of the use of mockgen, see the sample/ directory. In simple cases, you will need only the -source flag.

Building Mocks

type Foo interface {
  Bar(x int) int
}

func SUT(f Foo) {
 // ...
}

func TestFoo(t *testing.T) {
  ctrl := gomock.NewController(t)

  // Assert that Bar() is invoked.
  defer ctrl.Finish()

  m := NewMockFoo(ctrl)

  // Asserts that the first and only call to Bar() is passed 99.
  // Anything else will fail.
  m.
    EXPECT().
    Bar(gomock.Eq(99)).
    Return(101)

  SUT(m)
}

If you are using a Go version of 1.14+, a mockgen version of 1.5.0+, and are passing a *testing.T into gomock.NewController(t) you no longer need to call ctrl.Finish() explicitly. It will be called for you automatically from a self registered Cleanup function.

Building Stubs

type Foo interface {
  Bar(x int) int
}

func SUT(f Foo) {
 // ...
}

func TestFoo(t *testing.T) {
  ctrl := gomock.NewController(t)
  defer ctrl.Finish()

  m := NewMockFoo(ctrl)

  // Does not make any assertions. Executes the anonymous functions and returns
  // its result when Bar is invoked with 99.
  m.
    EXPECT().
    Bar(gomock.Eq(99)).
    DoAndReturn(func(_ int) int {
      time.Sleep(1*time.Second)
      return 101
    }).
    AnyTimes()

  // Does not make any assertions. Returns 103 when Bar is invoked with 101.
  m.
    EXPECT().
    Bar(gomock.Eq(101)).
    Return(103).
    AnyTimes()

  SUT(m)
}

Modifying Failure Messages

When a matcher reports a failure, it prints the received (Got) vs the expected (Want) value.

Got: [3]
Want: is equal to 2
Expected call at user_test.go:33 doesn't match the argument at index 1.
Got: [0 1 1 2 3]
Want: is equal to 1

Modifying `Want`

The Want value comes from the matcher's String() method. If the matcher's default output doesn't meet your needs, then it can be modified as follows:

gomock.WantFormatter(
  gomock.StringerFunc(func() string { return "is equal to fifteen" }),
  gomock.Eq(15),
)

This modifies the gomock.Eq(15) matcher's output for Want: from is equal to 15 to is equal to fifteen.

Modifying `Got`

The Got value comes from the object's String() method if it is available. In some cases the output of an object is difficult to read (e.g., []byte) and it would be helpful for the test to print it differently. The following modifies how the Got value is formatted:

gomock.GotFormatterAdapter(
  gomock.GotFormatterFunc(func(i interface{}) string {
    // Leading 0s
    return fmt.Sprintf("%02d", i)
  }),
  gomock.Eq(15),
)

If the received value is 3, then it will be printed as 03.

Debugging Errors

reflect vendoring error

cannot find package "."
... github.com/golang/mock/mockgen/model

If you come across this error while using reflect mode and vendoring dependencies there are three workarounds you can choose from:

Use source mode.
Include an empty import import _ "github.com/golang/mock/mockgen/model".
Add --build_flags=--mod=mod to your mockgen command.

This error is due to changes in default behavior of the go command in more recent versions. More details can be found in #494.

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