(using_tox)=
# Using Tox

The quality of code for `anomalib` maintained by using tools such as `black`, `mypy`, and `flake8`. In order to enforce these, we use Tox. This is also the reason why we don't have dependencies such as `pytest` in the `requirements.txt` file.

What is tox?
> `tox` aims to automate and standardize testing in Python. It is part of a larger vision of easing the packaging, testing and release process of Python software.

> It is a generic virtualenv management and test command line tool you can use for:
> - checking that your package installs correctly with different Python versions and interpreters
> - running your tests in each of the environments, configuring your test tool of choice
> - acting as a frontend to Continuous Integration servers, greatly reducing boilerplate and merging CI and shell-based testing. - from the [docs](https://tox.readthedocs.io/)

See [getting started](#setting-up-and-getting-started) to dive in and get `tox` working on your system. If you want to know more about the `tox.ini` file, check out the [brief explanation](#brief-explanation-of-`tox.ini`).

## Setting-up and Getting Started

Setting up tox is easy

1. Create new Conda environment
`conda create -n toxenv python=3.8`

2. Activate the environment
`conda activate toxenv`

3. Install tox
`pip install tox`

4. Run
`tox`
It should setup the environments and install the dependencies.

```{note} All developers are required to run tox before creating their MR. If you have setup pre-commit hooks then this step can be skipped.
```

## Brief Explanation of `tox.ini`

Here is a brief explanation of `tox.ini` for those who are interested. However, for more details, the readers are directed to the [official docs](https://tox.readthedocs.io/).

All `tox` files start with
`[tox]`

`isolated_build = True` tells tox to use a virtual environment instead of using the global python.

`skip_missing_interpreters = True` allows tox to run even if some specified environments are missing.

`envlist` This defines all the environments that tox should create. Take for example that we want to create an environment to run `black` formatter. We can name this environment as:

```
[tox]
envlist =
    black_env
```

Then to define the commands in this environment all we need to do is start a block with `[testenv:black_env]` and then define the dependencies and call the commands.

```
[testenv:black_env]
    deps = black
    commands = black .
```

For a more elaborate setup, refer to the `tox.ini` file in this repository.

## Useful Tox CheatSheet

- `tox -e envname[,name1,name2]` - to run only those environments
- `tox -r [envname..]` - to recreate all/specific environments. Handy when the requirements have changed
- `tox -l` - to list all environments