Question 80775 in Docker Question posted in
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I need advice on Go integration testing using Postgres db in Docker

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?

Tags:

2

Answers


  1. 0

    it is a docker net problem but golang:

    1. you can create a docker net, run both container in one net.doc
      or use network --network=host

    2. export postgres container’s port to localhost, and customers container link to localhost,-pxx:xx

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  2. 0

    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.

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