CharSource concatenated = CharSource.concat(cycle);

    String expected = "abcdabcd";

    // read the first 8 chars manually, since there's no equivalent to ByteSource.slice
    // TODO(cgdecker): Add CharSource.slice?
    StringBuilder builder = new StringBuilder();
    Reader reader = concatenated.openStream(); // no need to worry about closing
    for (int i = 0; i < 8; i++) {

  @AndroidIncompatible // No getJavaLangAccess in Android (at least not in the version we use).
  @J2ktIncompatible
  @GwtIncompatible // lazyStackTraceIsLazy()
  public void testLazyStackTraceWorksInProd() {
    // TODO(b/64442212): Remove this guard once lazyStackTrace() works in Java 9+.
    Integer javaVersion = Ints.tryParse(JAVA_SPECIFICATION_VERSION.value());
    if (javaVersion != null && javaVersion >= 9) {
      return;
    }

     * </p>
     *
     * @return the logger adapter factory
     */
    protected static LoggerAdapterFactory getLoggerAdapterFactory() {
        // TODO
        try {
            Class.forName("org.apache.commons.logging.LogFactory");
            return new JclLoggerAdapterFactory();
        } catch (final Throwable ignore) {

            }, () -> asListHtml(dictId));
        }
    }

    private static void validateStopwordsString(final String values, final String propertyName, final VaErrorHook hook) {
        // TODO validation
    }

    // ===================================================================================
    //                                                                              JSP

        .forAllPublicStaticMethods(Suppliers.class)
        .testNulls();
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection
  @AndroidIncompatible // TODO(cpovirk): ClassNotFoundException: com.google.common.base.Function
  public void testSuppliersSerializable() throws Exception {
    new ClassSanityTester()
        .setDefault(Duration.class, Duration.ofSeconds(1))

import com.google.common.cache.LocalCache.Strength;
import com.google.common.testing.EqualsTester;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests CacheBuilderSpec. TODO(user): tests of a few invalid input conditions, boundary
 * conditions.
 *
 * @author Adam Winer
 */
@NullUnmarked
public class CacheBuilderSpecTest extends TestCase {
  public void testParse_empty() {

      checkNonNegative(--successorCount);

      if (orderedNodeConnections != null) {
        orderedNodeConnections.remove(new NodeConnection.Succ<>((N) node));
      }
    }

    /*
     * TODO(cpovirk): `return (V) removedValue` once our checker permits that.
     *
     * (We promoted a class of warnings into errors because sometimes they indicate real problems.

# OAuth2 con Password (y hashing), Bearer con tokens JWT

Ahora que tenemos todo el flujo de seguridad, hagamos que la aplicación sea realmente segura, usando tokens <abbr title="JSON Web Tokens">JWT</abbr> y hashing de contraseñas seguras.

Este código es algo que puedes usar realmente en tu aplicación, guardar los hashes de las contraseñas en tu base de datos, etc.

Vamos a empezar desde donde lo dejamos en el capítulo anterior e incrementarlo.

## Acerca de JWT

// license that can be found in the LICENSE file.

// This wrapper uses syscall.Flock to prevent concurrent adb commands,
// so for now it only builds on platforms that support that system call.
// TODO(#33974): use a more portable library for file locking.

//go:build darwin || dragonfly || freebsd || illumos || linux || netbsd || openbsd

// This program can be used as go_android_GOARCH_exec by the Go tool.

### Crear un Engine

Un `engine` de SQLModel (en el fondo, realmente es un `engine` de SQLAlchemy) es lo que **mantiene las conexiones** a la base de datos.

Tendrías **un solo objeto `engine`** para todo tu código para conectar a la misma base de datos.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[14:18] hl[14:15,17:18] *}