I need advice on Go integration testing using Postgres db in Docker - postgresql

Question

I am very new to Go world. I have some db functions that I need to test.
So first I have a database.go file that connects to a postgres db:
import (
"fmt"
"gorm.io/driver/postgres"
"gorm.io/gorm"
"os"
)
var DB *gorm.DB
var err error
func Open() error {
dsn := fmt.Sprintf("host=%s user=%s password=%s dbname=%s port=%s sslmode=disable", os.Getenv("HOST"), os.Getenv("USER"),
os.Getenv("PASSWORD"), os.Getenv("DB"), os.Getenv("PORT"))
DB, err = gorm.Open(postgres.Open(dsn), &gorm.Config{})
if err != nil {
return err
}
return nil
}
Then I have a customers.go file with functions that interact with that db:
import (
"customers/cmd/database"
"time"
)
type Customers struct {
ID int
CustomerName string
Active bool
Balance float32
ActiveSince time.Time
}
func Get(id int) (Customers, error) {
var customer Customers
result := database.DB.First(&customer, id)
if result.Error != nil {
return Customers{}, result.Error
} else {
return customer, nil
}
}
This is all running in docker, there is customers container and postgres container. Now the question is how do I test my Get(id int) function? I was researching dockertest but that spins up a different db and my Get function uses the one I specified in database.go. So is there a standard Go way to test these functions?

Answer 1

it is a docker net problem but golang:
you can create a docker net, run both container in one net.doc
or use network --network=host
export postgres container's port to localhost, and customers container link to localhost,-pxx:xx

Answer 2

there is standard way of unit tesing in go. pl refer testing and testify/assert. Unit tests are typically written in xxx_test.go file next to the code.
coming to unit testing of db access layer code, one option would be to have a testenv helper and use it on these lines.
customers_test.go:
package dbaccess
import "testing"
func TestDbAccessLayer(t *testing.T) {
testEnv := testUtils.NewTestEnv()
// testEnv should do the required initialization e.g.
// start any mocked services, connection to database, global logger etc.
if err := testEnv.Start(); err != nil {
t.Fatal(err)
}
// at the end of the test, stop need to reset state
// e.g. clear any entries created by test in db
defer testEnv.Stop()
// add test code
// add required assertion to validate
}
have a separate docker-compose.yml file and use it with docker compose command to start/stop services like postgresdb.
go test command may be used to run the tests. refer to the command docs for details.