go学习-mock接口测试

gomock是Go官方提供的测试框架，可以使用它对代码中的那些接口类型进行mock，方便编写单元测试。

安装mockgen

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

构建mock

为数据库函数编写单元测试代码，可我们又不能在单元测试过程中连接真实的数据库，这个时候就需要mock DB这个接口来方便进行单元测试。
使用mockgen 工具来为生成相应的mock代码。通过执行下面的命令，我们就能在当前项目下生成一个mock文件夹，里面存放了一个mock_employees.go文件。
mockgen -source=employees.go -destination=mock/mock_employees.go -package=mock
mock_employees.go文件中的内容就是mock相关接口的代码了。
我们通常不需要编辑它，只需要在单元测试中按照规定的方式使用它们就可以了。
-source：包含要mock的接口的文件。
-destination：生成的源代码写入的文件。如果不设置此项，代码将打印到标准输出。
-package：用于生成的模拟类源代码的包名。如果不设置此项包名默认在原包名前添加mock_前缀。
-imports：在生成的源代码中使用的显式导入列表。值为foo=bar/baz形式的逗号分隔的元素列表，其中bar/baz是要导入的包，foo是要在生成的源代码中用于包的标识符。

mock文件 无需编辑

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

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

import (
	reflect "reflect"
	domain "server/domain"

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

// MockEmployeesRepository is a mock of EmployeesRepository interface.
type MockEmployeesRepository struct {
	ctrl     *gomock.Controller
	recorder *MockEmployeesRepositoryMockRecorder
}

// MockEmployeesRepositoryMockRecorder is the mock recorder for MockEmployeesRepository.
type MockEmployeesRepositoryMockRecorder struct {
	mock *MockEmployeesRepository
}

// NewMockEmployeesRepository creates a new mock instance.
func NewMockEmployeesRepository(ctrl *gomock.Controller) *MockEmployeesRepository {
	mock := &MockEmployeesRepository{ctrl: ctrl}
	mock.recorder = &MockEmployeesRepositoryMockRecorder{mock}
	return mock
}

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

// CreateEmployee mocks base method.
func (m *MockEmployeesRepository) CreateEmployee(arg0 *domain.Employees) error {
	m.ctrl.T.Helper()
	ret := m.ctrl.Call(m, "CreateEmployee", arg0)
	ret0, _ := ret[0].(error)
	return ret0
}

// CreateEmployee indicates an expected call of CreateEmployee.
func (mr *MockEmployeesRepositoryMockRecorder) CreateEmployee(arg0 interface{}) *gomock.Call {
	mr.mock.ctrl.T.Helper()
	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "CreateEmployee", reflect.TypeOf((*MockEmployeesRepository)(nil).CreateEmployee), arg0)
}

函数

func (repo *EmployeesRepository) CreateEmployee(employee *domain.Employees) (err error) {
	err = repo.db.Debug().Create(&employee).Error
	if err != nil {
		err = fmt.Errorf("[repository.r.CreateEmployee] failed: employee = %+v, error = %w ", employee, err)
		return
	}
	return
}

测试用例

package impl

import (
	"testing"
	"github.com/DATA-DOG/go-sqlmock"
	"github.com/magiconair/properties/assert"
	"gorm.io/driver/postgres"
	"gorm.io/gorm"

	"server/domain"
)

func getDBMock() (*gorm.DB, sqlmock.Sqlmock, error) {
	db, mock, err := sqlmock.New()
	if err != nil {
		return nil, nil, err
	}
	//defer db.Close()
	gdb, err := gorm.Open(postgres.New(postgres.Config{
		DriverName:           "postgres",
		PreferSimpleProtocol: true,
		Conn:                 db,
	}), &gorm.Config{})
	if err != nil {
		return nil, nil, err
	}
	return gdb, mock, nil
}
func TestEmployeesRepository_CreateEmployees(t *testing.T) {
	type fields struct {
		db *gorm.DB
	}
	type args struct {
		employees *domain.Employees
	}
	db, mock, err := getDBMock()
	assert.Equal(t, err, nil)
	tests := []struct {
		name    string
		fields  fields
		args    args
		invoke  func(args)
		wantErr bool
	}{
		{
			name: "create Employees successful",
			fields: fields{
				db: db,
			},
			args: args{employees: &domain.Employees{
				ID:0,
				Code:      "1",
				Name:"zhangsan",
				DepartmentID:1,
			}},
			invoke: func(args args) {
				mock.ExpectQuery("INSERT INTO (.+)").WithArgs(
					args.employees.Code, args.employees.Name,args.employees.DepartmentID,sqlmock.AnyArg(),sqlmock.AnyArg(),sqlmock.AnyArg()).
					WillReturnRows(sqlmock.NewRows([]string{"ID"}).AddRow(1))
			},
		},
		{
			name: "create Employees failed",
			fields: fields{
				db: db,
			},
			args: args{employees: &domain.Employees{
				Code:      "1",
				Name:"zhangsan",
				DepartmentID:2,
			}},
			invoke: func(args args) {
				mock.ExpectQuery("INSERT INTO (.+)").WithArgs(
					args.employees.Code,args.employees.Name,args.employees.DepartmentID,sqlmock.AnyArg(),sqlmock.AnyArg(),sqlmock.AnyArg()).
					WillReturnError(gorm.ErrInvalidData)
			},
			wantErr: true,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			c := &EmployeesRepository{
				db: tt.fields.db,
			}
			tt.invoke(tt.args)
			if err := c.CreateEmployee(tt.args.employees); (err != nil) != tt.wantErr {
				t.Errorf("CreateEmployees() error = %v, wantErr %v", err, tt.wantErr)
			}
		})
	}
}