README.md

go-mysql-mocker(gmm)

go-mysql-mocker(gmm) was created to provide developers with a reliable and straightforward tool for mocking MySQL interactions in Go applications, particularly for automated testing environments. By simulating a MySQL server, go-mysql-mocker allows developers to conduct unit tests without the overhead of setting up a real database, thus speeding up test cycles and reducing external dependencies. This is especially useful in continuous integration (CI) environments where test reliability and speed are paramount.

Dependencies

• go-mysql-server: used for MySQL memory server
• gorm: used for creating table and initializing data

Features

• Easy setup and integration with Go projects.
• Uses in-memory storage to speed up tests.
• Automatic table creation and data seeding using GORM models or SQL statements.

Requirements

• Go 1.20 (or later versions)

Installation

go get -u github.com/hedon954/go-mysql-mocker

Usage

• Port(port int): Sets the MySQL server port to the specified value. This method allows you to customize the port on which the MySQL server listens.
• CreateTable(model): Creates a database table based on the schema defined in the provided model. This method facilitates the automatic creation of tables directly from GORM models.
• InitData(data): Populates the database with test data using instances of Go structs. This method supports initializing data from single instances or slices of instances that implement the schema.Tabler interface.
• SQLStmts(stmts): Executes the provided SQL statements to generate test data. This method allows for direct insertion or modification of data using raw SQL commands.
• SQLFiles(files): Reads SQL statements from specified files and executes them to generate test data. This method is useful for initializing the database with a larger set of pre-defined SQL operations.
• Build(): Initializes and starts the MySQL server with all specified configurations and initializes the data. This method must be called to execute the configurations set up by the preceding methods.

Quick Start

prepare a data model and implement TableName() interface

type UserState struct {
	UID   string `gorm:"primaryKey;column:uid"`
	State string `gorm:"column:state"`
}

func (u UserState) TableName() string {
	return "user_state"
}

write a business logic

func ChangeUserStateToMatch(db *sql.DB, uid string) (int64, error) {
	res, err := db.Exec("UPDATE user_state SET state = 'match' WHERE uid = ?", uid)
	if err != nil {
		return 0, err
	}
	return res.RowsAffected()
}

use gmm to test it

func TestChangeUserStateToMatch(t *testing.T) {
	t.Run("no data should have no affect row", func(t *testing.T) {
		db, _, shutdown, err := gmm.Builder("db-name").Port(20201).CreateTable(UserState{}).Build()
		assert.Nil(t, err)
		defer shutdown()
		res, err := ChangeUserStateToMatch(db, "1")
		assert.Nil(t, err)
		assert.Equal(t, int64(0), res)
	})

	t.Run("has uid 1 should affect 1 row and change state to `match`", func(t *testing.T) {
		// prepare db and init data
		origin := UserState{State: "no-match", UID: "1"}
		db, gDB, shutdown, err := gmm.Builder().CreateTable(UserState{}).InitData(&origin).Build()
		assert.Nil(t, err)
		defer shutdown()

		// check before change state
		var before = UserState{}
		assert.Nil(t, gDB.Select("uid", "state").Where("uid=?", "1").Find(&before).Error)
		assert.Equal(t, origin, before)

		// run biz logic
		res, err := ChangeUserStateToMatch(db, "1")
		assert.Nil(t, err)
		assert.Equal(t, int64(1), res)

		// check after change state
		var after = UserState{}
		assert.Nil(t, gDB.Select("uid", "state").Where("uid=?", "1").Find(&after).Error)
		assert.Equal(t, UserState{
			UID:   "1",
			State: "match",
		}, after)
	})
}

For more detail, please see examples folder.