n-r-w/pglive

PostgreSQL live database unit testing in golang

pglive

PostgreSQL live database unit testing

Installation

go get github.com/n-r-w/pglive@latest

Introduction

• This package is used with https://github.com/jackc/pgx, because it returns pgxpool.Pool for database operations.
• Allow to use parallel unit tests. In this case, each test will have its own database.
• Test database is created and deleted automatically after the test is finished.

There are two operating modes: using Docker and using an external database.

Using Docker

In this case, the default mapping for PostgreSQL on the host is to port 5433 to avoid conflicts with local PostgreSQL. For Docker Desktop on Linux or macOS, you should define DOCKER_SOCKET_ENDPOINT environment variable with:

• Linux: unix:///home/<user>/.docker/desktop/docker.sock
• macOS: unix:///Users/<USER>/.docker/run/docker.sock

Using an external database

This mode is activated in the following cases:

• at least one parameter in Option are used: WithHost, WithPort, WithDatabase, WithUser, WithPassword
• at least one environment variable is set: POSTGRES_HOST, POSTGRES_PORT, POSTGRES_DB, POSTGRES_USER, POSTGRES_PASSWORD.

Can be activated in GitLab CI with the following settings in .gitlab-ci.yml. Setting POSTGRES_DB in GitLab environment variables doesn't make sense because the default database won't be used. Example of .gitlab-ci.yml file with PostgreSQL service and environment variables for go tests:

go tests:
  services:
    - name: postgres:16.2 # PostgreSQL image name from <https://hub.docker.com/_/postgres>
      alias: test-postgres
      command: ["-c", "max_connections=200"] # Increasing the number of connections (if you have a lot of parallel tests)
  variables: # Environment variables
    POSTGRES_USER: postgres # Username
    POSTGRES_PASSWORD: secret # Password
    POSTGRES_HOST: test-postgres # Hostname
    POSTGRES_HOST_AUTH_METHOD: trust
    GOFLAGS: # Flags for go test if needed (-tags=xxxx)

Known limitations in external database mode:

• The test database will not be deleted if the test execution is stopped on a breakpoint and not continued.

Parameter filling priority

• If specific value parameters are set (Host, Port, Database, User, Password), the values from these parameters are used.
• If environment variables are set and specific value parameters are not set, the values from the environment variables are used.
• If neither environment variables nor specific value parameters are set, default values are used.

Default values:

PostrgreSQL image: postgres:latest
PostrgreSQL Host: 127.0.0.1
PostrgreSQL port: 5432
PostrgreSQL mapping port: 5433 (Docker mode)
User: postgres
Password: secret

Usage example

import (
  "testing"

  "github.com/jackc/pgx/v5/pgxpool"
  "github.com/n-r-w/pglive"
)

func Test_Example(t *testing.T) {
    var db *pgxpool.Pool

    // Create test database, run migrations and return a database connection
    db = pglive.GetPool(t, "./migrations")

    rows, err := db.Query(context.Background(), "SELECT name FROM test_table")
    if err != nil {
        t.Fatalf("error: %s", err)
    }
    for rows.Next() {
        var name string
        if err := rows.Scan(&name); err != nil {
            t.Fatalf("error: %s", err)
        }
        if name != "test" {
            t.Fatalf("expected 'test', got '%s'", name)
        }
    }
}