assertTrue(iterator.hasNext());
    assertEquals("a", iterator.next());
    assertThrows(UnsupportedOperationException.class, () -> iterator.remove());
  }

  @SuppressWarnings("DoNotCall")
  public void testAdd() {
    ListIterator<String> iterator = create();

    assertTrue(iterator.hasNext());
    assertEquals("a", iterator.next());
    assertEquals("b", iterator.next());
    assertEquals("b", iterator.previous());

import java.util.SortedSet;
import org.junit.Ignore;

/**
 * Testers for {@link SortedSetMultimap#asMap}.
 *
 * @author Louis Wasserman
 * @param <K> The key type of the tested multimap.
 * @param <V> The value type of the tested multimap.
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")

import com.google.common.annotations.GwtCompatible;
import java.util.Queue;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates queues, containing sample elements, to be tested.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public interface TestQueueGenerator<E extends @Nullable Object> extends TestCollectionGenerator<E> {
  @Override
  Queue<E> create(Object... elements);

 * specifies to use <i>n</i> steps, a total of <i>3^n</i> tests are actually performed.
 *
 * <p>For instance, if <i>steps</i> is 5, one example sequence that will be tested is:
 *
 * <ol>
 *   <li>remove();
 *   <li>hasNext()
 *   <li>hasNext();
 *   <li>remove();
 *   <li>next();
 * </ol>
 *

I tested several ideas in the most popular Python editors: PyCharm, VS Code, Jedi based editors.

By the last <a href="https://www.jetbrains.com/research/python-developers-survey-2018/#development-tools" class="external-link" target="_blank">Python Developer Survey</a>, that covers about 80% of the users.

import java.util.Collection;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

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

 */

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> {

import com.google.common.annotations.GwtCompatible;
import java.util.Map;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates maps, containing sample elements, to be tested.
 *
 * @author George van den Driessche
 */
@GwtCompatible
@NullMarked
public interface TestMapGenerator<K extends @Nullable Object, V extends @Nullable Object>

   - If you edit, you’re a collaborator, not a reviewer, and cannot merge.

6. **Testing**:
   - Assume the submitter tested the code. If testing is unclear, ask for details (e.g., “How was this tested?”).
   - Reject untested PRs unless testing is infeasible, then assist with test setup.

## Tips for Success

 * limitations under the License.
 */

package com.google.common.collect.testing;

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

/**
 * Creates iterators to be tested.
 *
 * @param <E> the element type of the iterator.
 * @author George van den Driessche
 */
@GwtCompatible
public interface TestIteratorGenerator<E> {
  Iterator<E> get();