import com.google.common.testing.RelationshipTester.Item;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.ArrayList;
import java.util.List;
import org.jspecify.annotations.NullMarked;

/**
 * Tester for {@link Equivalence} relationships between groups of objects.
 *
 * <p>To use, create a new {@link EquivalenceTester} and add equivalence groups where each group

public class AbstractSetTester<E> extends AbstractCollectionTester<E> {
  /*
   * Previously we had a field named set that was initialized to the value of
   * collection in setUp(), but that caused problems when a tester changed the
   * value of set or collection but not both.
   */
  protected final Set<E> getSet() {
    return (Set<E>) collection;
  }

import java.util.Collection;
import java.util.List;
import java.util.Map.Entry;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;
import org.junit.Ignore;

/** Skeleton for a tester of a {@code BiMap}. */
@GwtCompatible
@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.

  public void testNulls() throws Exception {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicStaticMethods(LinkedListMultimap.class);
    tester.ignore(LinkedListMultimap.class.getMethod("get", Object.class));
    tester.ignore(LinkedListMultimap.class.getMethod("removeAll", Object.class));
    tester.testAllPublicInstanceMethods(LinkedListMultimap.create());
  }

  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testStringConverter_nullPointerTester() throws Exception {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicInstanceMethods(Doubles.stringConverter());
  }

  @GwtIncompatible
  public void testTryParse_withNullNoGwt() {
    assertThat(Doubles.tryParse("null")).isNull();

  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testStringConverter_nullPointerTester() throws Exception {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicInstanceMethods(Longs.stringConverter());
  }

  public void testTryParse() {
    tryParseAndAssertEquals(0L, "0");
    tryParseAndAssertEquals(0L, "-0");

  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testStringConverter_nullPointerTester() throws Exception {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicInstanceMethods(Shorts.stringConverter());
  }

  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNullPointers() {
    NullPointerTester tester = new NullPointerTester();
    tester.setDefault(double.class, 3.0);
    tester.testAllPublicStaticMethods(DoubleMath.class);
  }

import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.MapFeature;
import java.util.Iterator;
import org.junit.Ignore;

/**
 * Tester for {@code Multimap.entries}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")

### Casos de uso: servicio externo

Un ejemplo podría ser que tienes un proveedor de autenticación externo al que necesitas llamar.

Le envías un token y te devuelve un usuario autenticado.

Este proveedor podría estar cobrándote por cada request, y llamarlo podría tomar más tiempo adicional que si tuvieras un usuario de prueba fijo para los tests.