/*
 *
 * h2. Concerns for the plugin manager
 *
 * h3. resolving the dependencies of a plugin - these could be resolved remotely at runtime or, -
 * they could be resolved from a local repository - I think we need a simple dependency model here
 * that is more mercury related and not Maven related i.e. no POMs - workspace resolver - we need
 * tools to pre-populate this repository
 *
 * h3. create an isolated classloader
 *

We see that we are going to need some dependencies used in several places of the application.

So we put them in their own `dependencies` module (`app/dependencies.py`).

We will now use a simple dependency to read a custom `X-Token` header:

{* ../../docs_src/bigger_applications/app_an_py39/dependencies.py hl[3,6:8] title["app/dependencies.py"] *}

/// tip

Le tout conçu en composant réutilisable facilement intégrable à vos systèmes, data stores, base de données relationnelle ou NoSQL, etc.

### Injection de dépendances

FastAPI contient un système simple mais extrêmement puissant d'<abbr title='aussi connus sous le nom de "composants", "ressources", "services", "providers"'><strong>Injection de Dépendances</strong></abbr>.

 * it delegates to other components that potentially encounter problems. Then, the problem reporter can focus on
 * providing a simple error message, leaving the donkey work of creating a nice model problem to this component.
 *
 * @deprecated use {@code org.apache.maven.api.services.ModelBuilder} instead
 */
@Deprecated(since = "4.0.0")

 * under the License.
 */
package org.apache.maven.model.building;

/**
 * Describes a problem that was encountered during model building. A problem can either be an exception that was thrown
 * or a simple string message. In addition, a problem carries a hint about its source, e.g. the POM file that exhibits
 * the problem.
 *
 * @deprecated use {@code org.apache.maven.api.services.ModelBuilder} instead
 */

The `TestClient` is based on <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a>, and luckily, we can use it directly to test the API.

## Example { #example }

For a simple example, let's consider a file structure similar to the one described in [Bigger Applications](../tutorial/bigger-applications.md){.internal-link target=_blank} and [Testing](../tutorial/testing.md){.internal-link target=_blank}:

```

      assertThat(cache.asMap().entrySet()).containsExactly(immutableEntry(key2, value2));
    }
  }

  // fails in Maven with 64-bit JDK: https://github.com/google/guava/issues/1568

  // A simple type whose .toString() will return the same value each time, but without maintaining
  // a strong reference to that value.
  static class Key {
    private final int value;
    private WeakReference<String> toString;

      assertThat(cache.asMap().entrySet()).containsExactly(immutableEntry(key2, value2));
    }
  }

  // fails in Maven with 64-bit JDK: https://github.com/google/guava/issues/1568

  // A simple type whose .toString() will return the same value each time, but without maintaining
  // a strong reference to that value.
  static class Key {
    private final int value;
    private WeakReference<String> toString;

# Primeros Pasos { #first-steps }

El archivo FastAPI más simple podría verse así:

{* ../../docs_src/first_steps/tutorial001_py39.py *}

Copia eso en un archivo `main.py`.

Ejecuta el servidor en vivo:

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:solid">main.py</u>

import assertk.assertions.startsWith
import com.github.ajalt.clikt.core.parse
import java.io.IOException
import kotlin.test.Test
import okhttp3.RequestBody
import okio.Buffer

class MainTest {
  @Test
  fun simple() {
    val request = fromArgs("http://example.com").createRequest()
    assertThat(request.method).isEqualTo("GET")
    assertThat(request.url.toString()).isEqualTo("http://example.com/")
    assertThat(request.body).isNull()