# Testcontainers
[![Hex.pm](https://img.shields.io/hexpm/v/testcontainers.svg)](https://hex.pm/packages/testcontainers)
> Testcontainers is an Elixir library that supports ExUnit tests, providing lightweight, throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container.
## Table of Contents
- [Prerequisites](#prerequisites)
- [Installation](#installation)
- [Usage](#usage)
- [API Documentation](#api-documentation)
- [Contributing](#contributing)
- [License](#license)
- [Contact](#contact)
## Prerequisites
Before you begin, ensure you have met the following requirements:
- You have installed the latest version of [Elixir](https://elixir-lang.org/install.html)
- You have a [Docker](https://www.docker.com/products/docker-desktop) installed and running
- You are familiar with Elixir and Docker basics
## Installation
To add Testcontainers to your project, follow these steps:
1. Add `testcontainers` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:testcontainers, "~> x.x.x"}
]
end
```
2. Run mix deps.get
## Usage
This section explains how to use the Testcontainers library in your own project.
### In a Phoenix project:
In simple terms you can add this in application.ex:
```elixir
# In your application.ex file in your Phoenix project:
import Testcontainers.Ecto
@impl true
def start(_type, _args) do
postgres_container(app: :my_app),
# .. other setup code
end
```
see documentation on Testcontainers.Ecto for more information about the options it can take.
There is an example repo here with a bare bones phoenix application, where the only changes are the inclusion of the ecto macro and removing the test alias that interferes with the macro:
[https://github.com/jarlah/hello_testcontainers](https://github.com/jarlah/hello_testcontainers)
### Simple example
Here's a simple example of how to use a MySQL container in your tests:
```elixir
# test/a_simple_mysql_container_test.exs
defmodule ASimpleMySqlContainerTest do
use ExUnit.Case, async: true
import Testcontainers.ExUnit
alias Testcontainers.Container.MySqlContainer
describe "with default configuration" do
container(:mysql, MySqlContainer.new())
test "provides a ready-to-use mysql container", %{mysql: mysql} do
assert mysql.environment[:MYSQL_MAJOR] == "8.0"
end
end
end
```
### Global Setup
If you prefer to set up a globally shared database for all tests in the project, you can configure and run a container inside the test/test_helper.exs file:
```elixir
# test/test_helper.exs
import Testcontainers.ExUnit
alias Testcontainers.Container
alias Container.PostgresContainer
postgres =
PostgresContainer.new("postgres:latest")
|> Container.with_fixed_port(5432)
# or |> Container.with_fixed_port(5432, <OTHER_HOST_PORT>)
{:ok, _} = run_container(postgres, on_exit: nil)
ExUnit.start()
```
The container will be deleted by Ryuk after the test session ends.
NOTE: This will cause the test process to exit prematurely if the port is already used. Use with care!
### Logging
By default, Testcontainers doesn't log anything. If you want Testcontainers to log, set the desired log level in config/test.exs:
```elixir
# config/test.exs
import Config
config :testcontainers,
log_level: :warning
```
## API Documentation
For more detailed information about the API, different container configurations, and advanced usage scenarios, please refer to the [API documentation](https://hexdocs.pm/testcontainers/api-reference.html).
## Contributing
We welcome your contributions! Please see our contributing guidelines (TBD) for more details on how to submit patches and the contribution workflow.
## License
Testcontainers is available under the MIT license. See the LICENSE file for more info.
## Contact
If you have any questions, issues, or want to contribute, feel free to contact us.
---
Thank you for using Testcontainers to test your Elixir applications!