*/
  @Test
  public abstract void incidentEdges_checkReturnedSetMutability();

  @Test
  public void nodes_oneNode() {
    addNode(N1);
    assertThat(graph.nodes()).containsExactly(N1);
  }

  @Test
  public void nodes_noNodes() {
    assertThat(graph.nodes()).isEmpty();
  }

  @Test
  public void adjacentNodes_oneEdge() {
    putEdge(N1, N2);

import com.google.common.annotations.GwtCompatible;
import java.util.Set;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Creates sets, containing sample elements, to be tested.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface TestSetGenerator<E extends @Nullable Object> extends TestCollectionGenerator<E> {
  @Override

import com.google.common.testing.AbstractPackageSanityTests;

/** Basic sanity tests for classes in {@code common.base}. */

@GwtIncompatible
public class PackageSanityTests extends AbstractPackageSanityTests {
  public PackageSanityTests() {
    // package private classes like FunctionalEquivalence are tested through the public API.
    publicApiOnly();
  }

import com.google.common.annotations.GwtCompatible;
import java.util.Collection;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Creates collections, containing sample elements, to be tested.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface TestCollectionGenerator<E extends @Nullable Object>

import com.google.common.annotations.GwtCompatible;
import java.util.Set;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Creates sets, containing sample elements, to be tested.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface TestSetGenerator<E extends @Nullable Object> extends TestCollectionGenerator<E> {
  @Override

  return ops::Mul(ctx, inputs[0], inputs[1], &outputs[0], "Mul");
}

// TODO(vnvo2409): Add more tests from `python/ops/gradient_checker_v2_test.py`.
// These tests should not be confused with `[*]_grad_test` which compare the
// result of `gradient_checker` and `[*]_grad`. The tests here test the
// functionality of `gradient_checker` by comparing the result with expected
// manual user-provided gradients.

import com.google.common.collect.testing.features.MapFeature;
import org.junit.Ignore;

/**
 * Tester for the {@code containsKey} methods of {@code Multimap} and its {@code asMap()} view.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")

import java.util.Iterator;
import java.util.Map.Entry;
import org.junit.Ignore;

/**
 * Tester for {@code Multimap.keySet}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class MultimapKeySetTester<K, V> extends AbstractMultimapTester<K, V, Multimap<K, V>> {

import com.google.common.collect.Multiset;
import com.google.common.collect.testing.TestCollectionGenerator;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Creates multisets, containing sample elements, to be tested.
 *
 * @author Jared Levy
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface TestMultisetGenerator<E extends @Nullable Object>
    extends TestCollectionGenerator<E> {
  @Override

 */

package com.google.common.collect.testing.features;

import com.google.common.annotations.GwtCompatible;
import java.util.Set;

/**
 * Base class for enumerating the features of an interface to be tested.
 *
 * @param <T> The interface whose features are to be enumerated.
 * @author George van den Driessche
 */
@GwtCompatible
public interface Feature<T> {