# Testing

Toga provides a [`toga-dummy`](https://github.com/beeware/toga/tree/main/dummy) backend that can be used for testing purposes. This backend implements the full interface required by a platform backend, but does not display any widgets visually. It provides an API that can be used to verify widget operation.

## Prerequisites

The dummy backend has no prerequisites.

## Installation

The dummy backend must be installed manually:

```console
$ python -m pip install toga-dummy
```

To force Toga to use the dummy backend, it must either be the only backend that is installed in the current Python environment, or you must define the `TOGA_BACKEND` environment variable:

/// tab | macOS

```console
(venv) $ export TOGA_BACKEND=toga_dummy
```

///

/// tab | Linux

```console
(venv) $ export TOGA_BACKEND=toga_dummy
```

///

/// tab | Windows

```console
(venv) $ set TOGA_BACKEND=toga_dummy
```

///
