/// details | `.venv` or other name

You could create the virtual environment in a different directory, but there's a convention of calling it `.venv`.

///

## Activate the Virtual Environment { #activate-the-virtual-environment }

Activate the new virtual environment so that any Python command you run or package you install uses it.

/// tip

* [PyCharm](https://www.jetbrains.com/help/pycharm/creating-virtual-environment.html)

/// tip | 提示

通常你只需要在创建虚拟环境时执行此操作**一次**。

///

## 退出虚拟环境 { #deactivate-the-virtual-environment }

当你完成工作后，你可以**退出**虚拟环境。

<div class="termy">

```console
$ deactivate
```

</div>

## Using `TestClient` { #using-testclient }

/// info

To use `TestClient`, first install [`httpx`](https://www.python-httpx.org).

Make sure you create a [virtual environment](../virtual-environments.md), activate it, and then install it, for example:

```console
$ pip install httpx
```

///

Import `TestClient`.

Create a `TestClient` by passing your **FastAPI** application to it.

/// info

To receive uploaded files and/or form data, first install [`python-multipart`](https://github.com/Kludex/python-multipart).

Make sure you create a [virtual environment](../virtual-environments.md), activate it, and then install it, for example:

```console
$ pip install python-multipart
```

///

## Import `File` and `Form` { #import-file-and-form }

    bus.post(EVENT);

    List<String> events = catcher.getEvents();
    assertTrue("No events should be delivered synchronously.", events.isEmpty());

    // Now we find the task in our Executor and explicitly activate it.
    List<Runnable> tasks = executor.getTasks();
    assertEquals("One event dispatch task should be queued.", 1, tasks.size());

    tasks.get(0).run();

<div class="termy">

```console
$ cd ~/code/prisoner-of-azkaban

// You don't need to be in the old directory to deactivate, you can do it wherever you are, even after going to the other project 😎
$ deactivate

// Activate the virtual environment in prisoner-of-azkaban/.venv 🚀
$ source .venv/bin/activate

// Now when you run python, it will find the package sirius installed in this virtual environment ✨
$ python main.py

/// info

To use forms, first install [`python-multipart`](https://github.com/Kludex/python-multipart).

Make sure you create a [virtual environment](../virtual-environments.md), activate it, and then install it, for example:

```console
$ pip install python-multipart
```

///

/// note

This is supported since FastAPI version `0.113.0`. 🤓

///

/// info

To use forms, first install [`python-multipart`](https://github.com/Kludex/python-multipart).

Make sure you create a [virtual environment](../virtual-environments.md), activate it, and then install it, for example:

```console
$ pip install python-multipart
```

///

## Import `Form` { #import-form }

Import `Form` from `fastapi`:

For example, let's say you have 4 API endpoints (*path operations*):

* `/items/public/`
* `/items/private/`
* `/users/{user_id}/activate`
* `/items/pro/`

then you could add different permission requirements for each of them just with dependencies and sub-dependencies:

```mermaid
graph TB

current_user(["current_user"])

      <description>This is an activator which will detect an operating system's attributes in order
        to activate its profile.</description>
      <fields>
        <field>
          <name>name</name>
          <version>4.0.0+</version>
          <type>String</type>
          <description>
            The name of the operating system to be used to activate the profile. This must be an exact match