import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.time.Duration;

/** This class is for {@code com.google.common.base} use only! */
@J2ktIncompatible
@GwtIncompatible // java.time.Duration
final class Internal {

  /**
   * Returns the number of nanoseconds of the given duration without throwing or overflowing.
   *

from typing import Optional, Union

from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: Optional[str] = None


class ExtendedItem(Item):
    age: int


@app.post("/items/")
def save_union_different_body(item: Union[ExtendedItem, Item]):
    return {"item": item}


client = TestClient(app)

else:
    _ETREE_EXCEPTIONS = (SyntaxError, AttributeError, ValueError, TypeError)

_STS_NS = {'sts': 'https://sts.amazonaws.com/doc/2011-06-15/'}


class STSElement(object):
    """STS aware XML parsing class. Wraps a root element name and
    cElementTree.Element instance. Provides STS namespace aware parsing
    functions.

    """

    def __init__(self, root_name, element):

您可以在 shell 中创建和使用环境变量，而无需使用 Python：

//// tab | Linux、macOS、Windows Bash

<div class="termy">

```console
// 您可以创建一个名为 MY_NAME 的环境变量
$ export MY_NAME="Wade Wilson"

// 然后您可以与其他程序一起使用它，例如
$ echo "Hello $MY_NAME"

Hello Wade Wilson
```

</div>

////

//// tab | Windows PowerShell

<div class="termy">

```console
// 创建一个名为 MY_NAME 的环境变量
$ $Env:MY_NAME = "Wade Wilson"

@Timeout(30)
@Tag("Slow")
@Burst
class CancelTest(
  private val cancelMode: CancelMode = INTERRUPT,
  private val connectionType: ConnectionType = H2,
) {
  @JvmField @RegisterExtension
  val platform = PlatformRule()

  private var threadToCancel: Thread? = null

  enum class CancelMode {
    CANCEL,
    INTERRUPT,
  }

  enum class ConnectionType {
    H2,
    HTTPS,
    HTTP,
  }

Gracias a <a href="https://www.starlette.dev/testclient/" class="external-link" target="_blank">Starlette</a>, escribir pruebas para aplicaciones de **FastAPI** es fácil y agradable.

Está basado en <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a>, que a su vez está diseñado basado en Requests, por lo que es muy familiar e intuitivo.

# Тестирование { #testing }

Благодаря <a href="https://www.starlette.dev/testclient/" class="external-link" target="_blank">Starlette</a>, тестировать приложения **FastAPI** легко и приятно.

Тестирование основано на библиотеке <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a>, которая в свою очередь основана на библиотеке Requests, так что все действия знакомы и интуитивно понятны.

El `TestClient` está basado en <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a>, y afortunadamente, podemos usarlo directamente para probar la API.

## Ejemplo { #example }

import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * Methods factored out so that they can be emulated differently in GWT.
 *
 * @author Hayward Chan
 */
@GwtCompatible
final class Platform {
  /** Returns the platform preferred implementation of a map based on a hash table. */
  static <K extends @Nullable Object, V extends @Nullable Object>
      Map<K, V> newHashMapWithExpectedSize(int expectedSize) {

@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class MapMergeTester<K, V> extends AbstractMapTester<K, V> {
  @MapFeature.Require(SUPPORTS_PUT)
  public void testAbsent() {
    assertEquals(
        "Map.merge(absent, value, function) should return value",
        v3(),