# Development environment¶

tox can be used for just preparing different virtual environments required by a project.

This feature can be used by deployment tools when preparing deployed project environments. It can also be used for setting up normalized project development environments and thus help reduce the risk of different team members using mismatched development environments.

Here are some examples illustrating how to set up a project’s development environment using tox. For illustration purposes, let us call the development environment devenv.

## Example 1: Basic scenario¶

### Step 1 - Configure the development environment¶

First, we prepare the tox configuration for our development environment by defining a [testenv:devenv] section in the project’s tox.ini configuration file:

[testenv:devenv]
envdir = devenv
basepython = python2.7
usedevelop = True


In it we state:

• what directory to locate the environment in,
• what Python executable to use in the environment,
• that our project should be installed into the environment using setup.py develop, as opposed to building and installing its source distribution using setup.py install.

Actually, we can configure a lot more, and these are only the required settings. For example, we can add the following to our configuration, telling tox not to reuse commands or deps settings from the base [testenv] configuration:

[testenv:devenv]
commands =
deps =


### Step 2 - Create the development environment¶

Once the [testenv:devenv] configuration section has been defined, we create the actual development environment by running the following:

tox -e devenv


This creates the environment at the path specified by the environment’s envdir configuration value.

## Example 2: A more complex scenario¶

Let us say we want our project development environment to:

• be located in the devenv directory,
• use Python executable python2.7,
• pull packages from requirements.txt, located in the same directory as tox.ini.

Here is an example configuration for the described scenario:

[testenv:devenv]
envdir = devenv
basepython = python2.7
usedevelop = True
deps = -rrequirements.txt