# Testing { #testing }

Thanks to <a href="https://www.starlette.dev/testclient/" class="external-link" target="_blank">Starlette</a>, testing **FastAPI** applications is easy and enjoyable.

It is based on <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a>, which in turn is designed based on Requests, so it's very familiar and intuitive.

deprecated APIs with their replacements. Access this feature from the _Search Anywhere_ dialog
(double-press shift) or under the _Analyze_ menu.

We’ve included deprecated APIs in OkHttp 4.0 because they make migration easy. We will remove them
in a future release! If you’re skipping releases, it’ll be much easier if you upgrade to OkHttp 4.0
as an intermediate step.

#### Vars and Vals

[build-system]
requires = ["pdm-backend"]
build-backend = "pdm.backend"

[project]
name = "fastapi"
dynamic = ["version"]
description = "FastAPI framework, high performance, easy to learn, fast to code, ready for production"
readme = "README.md"
license = "MIT"
license-files = ["LICENSE"]
requires-python = ">=3.9"
authors = [
    { name = "Sebastián Ramírez", email = "******@****.***" },
]
classifiers = [

MockWebServer
=============

A scriptable web server for testing HTTP clients


### Motivation

This library makes it easy to test that your app Does The Right Thing when it
makes HTTP and HTTPS calls. It lets you specify which responses to return and
then verify that requests were made as expected.

Because it exercises your full HTTP stack, you can be confident that you're

**FastAPI** has a very powerful but intuitive **<abbr title="also known as components, resources, providers, services, injectables">Dependency Injection</abbr>** system.

It is designed to be very simple to use, and to make it very easy for any developer to integrate other components with **FastAPI**.

## What is "Dependency Injection" { #what-is-dependency-injection }

 *
 * @author Colin Decker
 */
final class SubscriberRegistry {

  /**
   * All registered subscribers, indexed by event type.
   *
   * <p>The {@link CopyOnWriteArraySet} values make it easy and relatively lightweight to get an
   * immutable snapshot of all current subscribers to an event without any locking.
   */
  private final ConcurrentMap<Class<?>, CopyOnWriteArraySet<Subscriber>> subscribers =

centers. OkHttp supports modern TLS features (TLS 1.3, ALPN, certificate pinning). It can be
configured to fall back for broad connectivity.

Using OkHttp is easy. Its request/response API is designed with fluent builders and immutability. It
supports both synchronous blocking calls and async calls with callbacks.

A well behaved user agent
-------------------------

  }
}

// Work around issue 8826, where the Sentry SDK assumes that OkHttp's internal-visibility symbols
// will be suffixed '$okhttp' in deployable artifacts. This isn't intended to be a published API,
// but it's easy enough for us to keep it working. https://github.com/square/okhttp/issues/8826
tasks.withType<KotlinCompile> {
  compilerOptions {
    freeCompilerArgs = listOf("-module-name=okhttp")
  }
}

# Generating SDKs { #generating-sdks }

Because **FastAPI** is based on the **OpenAPI** specification, its APIs can be described in a standard format that many tools understand.

This makes it easy to generate up-to-date **documentation**, client libraries (<abbr title="Software Development Kits">**SDKs**</abbr>) in multiple languages, and **testing** or **automation workflows** that stay in sync with your code.

For external plugins, it's difficult for an object to be used outside the application of a plugin, so following best practices is relatively straightforward.  For core plugins in gradle/gradle, it's easy for an object to be created without applying its associated plugin. For instance, Spring has a plugin that uses the Checkstyle task directly without applying the Checkstyle plugin.