Go Testing + MySQL + TestContainer

1.txt

$go test ./... -cover -v  

=== RUN   TestSuccessWithGetDataByID
2025/01/29 22:24:37 github.com/testcontainers/testcontainers-go - Connected to docker: 
  Server Version: 27.4.0
  API Version: 1.46
  Operating System: Docker Desktop
  Total Memory: 11948 MB
  Testcontainers for Go Version: v0.35.0
  Resolved Docker Host: unix:///var/run/docker.sock
  Resolved Docker Socket Path: /var/run/docker.sock
  Test SessionID: 8e25c4b653a5628ce04b68596f77da89abc103ef9691667f86ed825f1cdba63b
  Test ProcessID: b6c35f7a-21d5-4958-9c80-0325646acd02
2025/01/29 22:24:41 🐳 Creating container for image mysql:8.0.36
2025/01/29 22:24:41 🐳 Creating container for image testcontainers/ryuk:0.11.0
2025/01/29 22:24:41 ✅ Container created: bfcf34699fad
2025/01/29 22:24:41 🐳 Starting container: bfcf34699fad
2025/01/29 22:24:42 ✅ Container started: bfcf34699fad
2025/01/29 22:24:42 ⏳ Waiting for container id bfcf34699fad image: testcontainers/ryuk:0.11.0. Waiting for: &{Port:8080/tcp timeout:<nil> PollInterval:100ms skipInternalCheck:false}
2025/01/29 22:24:42 🔔 Container is ready: bfcf34699fad
2025/01/29 22:24:42 ✅ Container created: a5052fbf4db2
2025/01/29 22:24:42 🐳 Starting container: a5052fbf4db2
2025/01/29 22:24:42 ✅ Container started: a5052fbf4db2
2025/01/29 22:24:42 ⏳ Waiting for container id a5052fbf4db2 image: mysql:8.0.36. Waiting for: &{timeout:<nil> Log:port: 3306  MySQL Community Server IsRegexp:false Occurrence:1 PollInterval:100ms check:<nil> submatchCallback:<nil> re:<nil> log:[]}
2025/01/29 22:24:48 🔔 Container is ready: a5052fbf4db2
--- PASS: TestSuccessWithGetDataByID (10.46s)
PASS
coverage: 75.0% of statements
ok  	demo/db	10.980s	coverage: 75.0% of statements

db.go

package db

import "database/sql"

type User struct {
	ID   int
	Name string
}

type DB struct {
	db *sql.DB
}

func NewDB(db *sql.DB) *DB {
	return &DB{db: db}
}

func (d *DB) FindById(id int) (*User, error) {
	var user User
	err := d.db.QueryRow("SELECT id, name FROM users WHERE id = ?", id).Scan(&user.ID, &user.Name)
	if err == sql.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	return &user, nil
}

db_2_test.go

package db_test

import (
	"context"
	"database/sql"
	"demo/db"
	"path/filepath"
	"testing"

	_ "github.com/go-sql-driver/mysql"
	"github.com/stretchr/testify/assert"
	"github.com/testcontainers/testcontainers-go/modules/mysql"
)

func TestDB(t *testing.T) {
	// Setup test container once for all tests
	ctx := context.Background()
	mysqlContainer, err := mysql.Run(ctx,
		"mysql:8.0.36",
		mysql.WithDatabase("demo-data"),
		mysql.WithUsername("user01"),
		mysql.WithPassword("pass01"),
		mysql.WithScripts(filepath.Join("testdata", "schema.sql")),
	)
	if err != nil {
		assert.Fail(t, "failed to start container")
	}

	connStr, err := mysqlContainer.ConnectionString(ctx)
	if err != nil {
		assert.Fail(t, "failed to get connection string")
	}

	_db, err := sql.Open("mysql", connStr)
	if err != nil {
		assert.Fail(t, "failed to open db connection")
	}
	defer _db.Close()

	testDB := db.NewDB(_db)

	t.Run("Success get user by ID", func(t *testing.T) {
		user, err := testDB.FindById(1)
		assert.Nil(t, err)
		assert.Equal(t, 1, user.ID)
		assert.Equal(t, "Somkiat", user.Name)
	})

	t.Run("Not found user by ID", func(t *testing.T) {
		user, err := testDB.FindById(999)
		assert.Nil(t, err)
		assert.Nil(t, user)
	})
}

db_test.go

package db_test

import (
	"context"
	"database/sql"
	"demo/db"
	"path/filepath"
	"testing"

	_ "github.com/go-sql-driver/mysql"
	"github.com/stretchr/testify/assert"
	"github.com/testcontainers/testcontainers-go/modules/mysql"
)

// Testing with testcontainers + mysql

func TestSuccessWithGetDataByID(t *testing.T) {
	// Start a new container of MySQL Database
	ctx := context.Background()
	mysqlContainer, err := mysql.Run(ctx,
		"mysql:8.0.36",
		mysql.WithDatabase("demo-data"),
		mysql.WithUsername("user01"),
		mysql.WithPassword("pass01"),
		mysql.WithScripts(filepath.Join("testdata", "schema.sql")),
	)

	if err != nil {
		assert.Fail(t, "failed to start container")
	}

	connStr, err := mysqlContainer.ConnectionString(ctx)
	if err != nil {
		assert.Fail(t, "failed to get connection string")
	}

	// Act
	_db, err := sql.Open("mysql", connStr)
	testDB := db.NewDB(_db)
	user, err := testDB.FindById(1)

	// Assert
	assert.Nil(t, err)
	assert.Equal(t, 1, user.ID)
	assert.Equal(t, "Somkiat", user.Name)
}

schema.sql

CREATE TABLE IF NOT EXISTS users (
		id INT PRIMARY KEY AUTO_INCREMENT,
		name VARCHAR(255) NOT NULL
);

INSERT INTO users (name) VALUES ('Somkiat');