Testcontainers module for Postgres

testcontainers-postgres simplifies the creation and management of Postgres containers for testing purposes using the Testcontainers library.

Installation

Add the library to the test section in your application’s Gemfile:

ruby group :test do gem "testcontainers-postgres" end

And then execute:

bash $ bundle install

Or install it yourself as:

bash $ gem install testcontainers-postgres

Usage

To use the library, you first need to require it:

ruby require "testcontainers/postgres"

Creating a Postgres container

Create a new instance of the Testcontainers::PostgresContainer class:

ruby container = Testcontainers::PostgresContainer.new

This creates a new container with the default Postgres image, user, password, and database. You can customize these by passing arguments to the constructor:

ruby container = Testcontainers::PostgresContainer.new("postgres:11", username: "custom_user", password: "custom_pass", database: "custom_db")

Starting and stopping the container

Start the container:

ruby container.start

Stop the container when you’re done:

ruby container.stop

Connecting to the Postgres container

Once the container is running, you can obtain the connection details using the following methods:

ruby host = container.host port = container.first_mapped_port

Or, you can generate a full database URL:

ruby database_url = container.database_url

Use this URL to connect to the Postgres container using your preferred postgres client library.

Customizing the container

You can also customize the container using the following methods:

ruby container.with_database("custom_db") container.with_username("custom_user") container.with_password("custom_pass")

Example

Here’s a complete example of how to use testcontainers-postgres to create a container, connect to it, and run a simple query:

```ruby require “testcontainers/postgres” require “pg”

container = Testcontainers::PostgresContainer.new container.start

client = PG.connect(container.database_url)

result = client.exec(“SELECT 1 AS number”) result.each do |row| puts row.inspect end

client.close container.stop ```

This example creates a Postgres container, connects to it using the pg gem, runs a simple SELECT 1 as number query, and then stops the container.

Using with RSpec

You can manage the container in the before(:suite) / after(:suite) blocks in your spec_helper.rb:

```ruby RSpec.configure do |config| # This helps us to have access to the RSpec.configuration.postgres_container without using global variables. config.add_setting :postgres_container, default: nil

config.before(:suite) do config.postgres_container = Testcontainers::PostgresContainer.new.start ENV[“DATABASE_URL”] = config.postgres_container.database_url # or you can expose it to a fixed port and use database.yml for configuration end

config.after(:suite) do config.postgres_container&.stop config.postgres_container&.remove end end ```

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/testcontainers/testcontainers-ruby. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Testcontainers project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.