try {
            fileTypeHelper.init();
        } catch (Exception e) {
            fail("init() should not throw an exception: " + e.getMessage());
        }
    }

    public void test_add() {
        fileTypeHelper.add("application/pdf", "pdf");
        assertEquals("pdf", fileTypeHelper.get("application/pdf"));

        fileTypeHelper.add("text/plain", "text");

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

/**
 * Creates collections containing unhashable sample elements, to be tested.
 *
 * @author Regina O'Dell
 */
@GwtCompatible
@NullMarked
public abstract class TestUnhashableCollectionGenerator<T extends Collection<UnhashableObject>>
    implements TestCollectionGenerator<UnhashableObject> {

  }

  // The Maps returned by Maps.filterEntries(), Maps.filterKeys(), and
  // Maps.filterValues() are not tested with removeIf() since Maps are not
  // Iterable.  Those returned by Iterators.filter() and Iterables.filter()
  // are not tested because they are unmodifiable.

  public void testConsumingIterable() {
    // Test data
    List<String> list = new ArrayList<>(asList("a", "b"));

 * object being tested for equality to the custom interface. {@code ForwardingObject} implements no
 * such custom interfaces directly; they are implemented only in subclasses. Therefore, forwarding
 * {@code equals} would break symmetry, as the forwarding object might consider itself equal to the
 * object being tested, but the reverse could not be true. This behavior is consistent with the

    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 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);

        assertEquals(1, helper.duplicateHostList.size());
        assertEquals("www.test.com", helper.duplicateHostList.get(0).getRegularName());
    }

    public void test_add() {
        DuplicateHostHelper helper = new DuplicateHostHelper();

        DuplicateHost testHost = new DuplicateHost();
        testHost.setRegularName("www.test.com");

| Android default  | ✅      | Android 10+  | [BoringSSL]     |                                                              |
| [GraalVM]        | ✅      |              | [OpenJDK]       | Only actively tested with JDK 11, not with 8 target          |
| [Bouncy Castle]  | ✅      |              | [Bouncy Castle] | [Tracking bug.][bug5698]                                     |

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

/**
 * Creates sets, containing sample elements, to be tested.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public interface TestListGenerator<E extends @Nullable Object> extends TestCollectionGenerator<E> {
  @Override
  List<E> create(Object... elements);

import org.jspecify.annotations.Nullable;
import org.junit.Ignore;

/**
 * Testers for {@link SetMultimap#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")