# Run Tests in Containers

## Configure the Test Run

Regardless of the scaling option you go with (Selenoid, Zalenium, Docker vs Kubernetes, etc.), you will need to connect your tests to a **Remote URL.**

You can do this two ways:

* Update <mark style="color:yellow;">**remote\_url**</mark> in **`pylenium.json`**
* Pass in the argument when running the tests in the CLI

### Run Tests in CLI

{% hint style="info" %}
This is the most common option since it is what you will use in your pipelines and CI
{% endhint %}

{% code title="Terminal" %}

```bash
pytest tests/ui -n 2 --remote_url="http://localhost:4444/wd/hub"
```

{% endcode %}

### Update pylenium.json

{% code title="pylenium.json" %}

```bash
"remote_url": "http://localhost:4444/wd/hub"
```

{% endcode %}

You can have multiple `pylenium.json` files, so you might have:

* **`dev-pylenium.json`** for local development
* **`ci-pylenium.json`** for CI Pipelines

Then pick which config file to use in the CLI. For example, in a CI Pipeline:

{% code title="Terminal" %}

```bash
pytest pylenium_json=ci-pylenium.json
```

{% endcode %}

### Config Layers

* Layer 1 - `pylenium.json` is deserialized into **PyleniumConfig**
* Layer 2 - If there are any CLI args, they will override their respective values in **PyleniumConfig**

## Docker Example

With **Docker** installed, you can easily spin up a **Selenium Grid** with the `docker-compose` command.

### docker-compose.yml

You will need a `docker-compose.yml` file and then open a Terminal in the same directory as this file.

{% code title="docker-compose.yml" %}

```yaml
version: "3"
services:

  selenium-hub:
    image: selenium/hub
    ports:
      - "4444:4444"
    environment:
        GRID_MAX_SESSION: 16
        GRID_BROWSER_TIMEOUT: 300
        GRID_TIMEOUT: 300

  chrome:
    image: selenium/node-chrome
    depends_on:
      - selenium-hub
    environment:
      HUB_PORT_4444_TCP_ADDR: selenium-hub
      HUB_PORT_4444_TCP_PORT: 4444
      NODE_MAX_SESSION: 2
      NODE_MAX_INSTANCES: 2

  firefox:
    image: selenium/node-firefox
    depends_on:
      - selenium-hub
    environment:
      HUB_PORT_4444_TCP_ADDR: selenium-hub
      HUB_PORT_4444_TCP_PORT: 4444
      NODE_MAX_SESSION: 4
      NODE_MAX_INSTANCES: 4
```

{% endcode %}

This configuration will spin up a **Hub** node (load balancer), a **Chrome** node with 2 available drivers and a **Firefox** node with 4 available drivers.

### Spin up the Grid

With a single command you will have all of this created for you:

{% code title="Terminal $" %}

```bash
docker-compose up -d
```

{% endcode %}

{% hint style="info" %}
Once complete, you can visually see this Grid by going to <http://localhost:4444/grid/console>
{% endhint %}

Now **Configure the Test Run** (steps at top of this doc) to target the Hub which will balance the tests across its Nodes.

### Scale Nodes

With the YAML file example above, it will create 1 chrome Node with 2 available drivers by default. You can easily scale this to the number you need.

{% code title="Terminal $" %}

```bash
docker-compose up -d --scale chrome=5
```

{% endcode %}

This will spin up the Grid with 5 chrome Nodes!

### Tear Down the Grid

When you're done using the Grid, a single command will tear it completely down.

{% code title="Terminal $" %}

```bash
docker-compose down
```

{% endcode %}