}

    @Test
    void testLoadBalancerAccess() {
        ChannelLoadBalancer balancer = channelManager.getLoadBalancer();
        assertNotNull(balancer);

        // Should return same instance
        assertSame(balancer, channelManager.getLoadBalancer());
    }

    @Test
    void testChannelFailureHandling() throws UnknownHostException {

    if (comparator == null) {
      comparator =
          new Comparator<K>() {
            @SuppressWarnings("unchecked")
            @Override
            public int compare(K o1, K o2) {
              return ((Comparable) o1).compareTo(o2);
            }
          };
    }
    Iterator<Entry<K, V>> entryItr = navigableMap.entrySet().iterator();
    Entry<K, V> prevEntry = entryItr.next();

                new DefaultDependencyCoordinatesFactory(),
                new DefaultVersionParser(new DefaultModelVersionParser(new MavenVersionScheme())),
                dependencyResolver));
        return services;
    }

    @Test
    void testTrivialConsumer() throws Exception {
        InternalMavenSession.from(InternalSession.from(session))
                .getMavenSession()
                .getRequest()

在高级使用场景中，如果不想使用「缓存」值，而是为需要在同一请求的每一步操作（多次）中都实际调用依赖项，可以把 `Depends` 的参数 `use_cache` 的值设置为 `False` :

```Python hl_lines="1"
async def needy_dependency(fresh_value: str = Depends(get_value, use_cache=False)):
    return {"fresh_value": fresh_value}
```

## 小结

千万别被本章里这些花里胡哨的词藻吓倒了，其实**依赖注入**系统非常简单。

依赖注入无非是与*路径操作函数*一样的函数罢了。

但它依然非常强大，能够声明任意嵌套深度的「图」或树状的依赖结构。

/// tip | 提示

这些简单的例子现在看上去虽然没有什么实用价值，

Por exemplo, se você quiser ler ou manipular o corpo da requisição antes que ele seja processado pela sua aplicação.

/// danger | Cuidado

Isso é um recurso "avançado".

Se você for um iniciante em **FastAPI** você deve considerar pular essa seção.

///

## Casos de Uso { #use-cases }

Alguns casos de uso incluem:

        assertFalse(CharUtil.isUrlChar(' ')); // space
        assertFalse(CharUtil.isUrlChar('\t')); // tab
        assertFalse(CharUtil.isUrlChar('\n')); // newline
        assertFalse(CharUtil.isUrlChar('\r')); // carriage return
        assertFalse(CharUtil.isUrlChar('<')); // less than
        assertFalse(CharUtil.isUrlChar('>')); // greater than
        assertFalse(CharUtil.isUrlChar('"')); // double quote

  # Repack the wheel. When repacking, the wheel would be automatically tagged
  # with the new tag we provided in ${whl_tag}. Repacking also regnerates the
  # RECORD file which contains hashes of all included files.
  python3 -m wheel pack "${pkg_name}"
done

# Switch back to the original working directory. This is needed to ensure that

        assertTrue(DialectVersion.SMB311.compareTo(DialectVersion.SMB1) > 0);
        assertEquals(0, DialectVersion.SMB302.compareTo(DialectVersion.SMB302));
    }

    @Test
    @DisplayName("Should return consistent ordinal values")
    void testOrdinalValues() {
        // Ordinal values should be consistent with enum declaration order
        assertTrue(DialectVersion.SMB1.ordinal() < DialectVersion.SMB202.ordinal());

    new IteratorTester<E>(
        Platform.collectionIteratorTesterNumIterations(), features, elements, knownOrder) {
      @Override
      protected Iterator<E> newTargetIterator() {
        resetCollection();
        return collection.iterator();
      }

      @Override
      protected void verify(List<E> elements) {
        expectContents(elements);
      }
    }.test();
  }

            external API with the notification of the invoice event
            (e.g. "payment successful").
    """
    # Send the invoice, collect the money, send the notification (the callback)
    return {"msg": "Invoice received"}


app.include_router(subrouter, callbacks=events_callback_router.routes)

client = TestClient(app)


def test_get():
    response = client.post(