# Testen { #testing }

Dank [Starlette](https://www.starlette.dev/testclient/) ist das Testen von **FastAPI**-Anwendungen einfach und macht Spaß.

Es basiert auf [HTTPX](https://www.python-httpx.org), welches wiederum auf der Grundlage von Requests konzipiert wurde, es ist also sehr vertraut und intuitiv.

Damit können Sie [pytest](https://docs.pytest.org/) direkt mit **FastAPI** verwenden.

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

/// info | Info

  protected final <T> void setDefault(Class<T> type, T value) {
    tester.setDefault(type, value);
  }

  /**
   * Sets two distinct values for {@code type}. These values can be used for both null pointer
   * testing and equals testing.
   *
   * @since 17.0
   */
  protected final <T> void setDistinctValues(Class<T> type, T value1, T value2) {
    tester.setDistinctValues(type, value1, value2);
  }

Et il existe aussi plusieurs façons d'obtenir de l'aide.

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## Suivre FastAPI sur X (Twitter) { #follow-fastapi-on-x-twitter }

        assertTrue(protocolHelper.isValidFileProtocol("s3://123bucket/path"));
        assertTrue(protocolHelper.isValidFileProtocol("s3://bucket/path/to/deep/nested/file.txt"));
        assertTrue(protocolHelper.isValidFileProtocol("s3://bucket/path/ファイル.txt"));
        assertTrue(protocolHelper.isValidFileProtocol("s3://bucket/path/file%20with%20spaces.txt"));

        // GCS URLs

    return big.bitLength() <= 31;
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNullPointers() {
    NullPointerTester tester = new NullPointerTester();
    tester.setDefault(int.class, 1);
    tester.testAllPublicStaticMethods(IntMath.class);
  }

  @GwtIncompatible // isPrime is GWT-incompatible
  public void testIsPrime() {
    // Defer correctness tests to Long.isPrime

* PostgreSQL
* MySQL
* SQLite
* Oracle
* Microsoft SQL Server, etc.

En este ejemplo, usaremos **SQLite**, porque utiliza un solo archivo y Python tiene soporte integrado. Así que puedes copiar este ejemplo y ejecutarlo tal cual.

Más adelante, para tu aplicación en producción, es posible que desees usar un servidor de base de datos como **PostgreSQL**.

/// tip | Consejo

import org.gradle.api.file.FileTree;
import org.gradle.api.model.ObjectFactory;
import org.gradle.api.tasks.Input;
import org.gradle.api.tasks.InputFiles;
import org.gradle.api.tasks.Internal;
import org.gradle.api.tasks.Nested;
import org.gradle.api.tasks.OutputDirectory;
import org.gradle.api.tasks.SkipWhenEmpty;
import org.gradle.api.tasks.TaskAction;
import org.gradle.api.tasks.util.PatternFilterable;
import org.gradle.api.tasks.util.PatternSet;

    /** The search engine client for interacting with OpenSearch. */
    @Resource
    public SearchEngineClient searchEngineClient;

    /**
     * A nested class for parsing command-line options.
     */
    protected static class Options {
        /** The session ID for the suggest creation process. */

You also get error checks for incorrect type operations:

<img src="/img/tutorial/body/image04.png">

This is not by chance, the whole framework was built around that design.

And it was thoroughly tested at the design phase, before any implementation, to ensure it would work with all the editors.

There were even some changes to Pydantic itself to support this.

        assertTrue(buf.toString().contains("Test error message"));
        assertTrue(buf.toString().contains("RuntimeException"));
    }

    // Test appendException method with nested exception
    @Test
    public void test_appendException_nestedException() {
        StringBuilder buf = new StringBuilder();
        Exception cause = new IllegalArgumentException("Root cause");