* work during upgrades. However it is generally inadvisable for <i>libraries</i> (which get
 * included on users' CLASSPATHs, outside the library developers' control) to do so.
 *
 * @author Kevin Bourrillion
 */
@Retention(RetentionPolicy.CLASS)
@Target({
  ElementType.ANNOTATION_TYPE,
  ElementType.CONSTRUCTOR,
  ElementType.FIELD,
  ElementType.METHOD,
  ElementType.TYPE
})
@Documented

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>

import java.util.Collections;
import java.util.Iterator;
import java.util.NoSuchElementException;
import junit.framework.TestCase;

/**
 * Unit test for {@link MinimalIterable}.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
public class MinimalIterableTest extends TestCase {

  public void testOf_empty() {
    Iterable<String> iterable = MinimalIterable.<String>of();

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

/**
 * An abstract TestSetGenerator for generating sets containing enum values.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public abstract class TestEnumSetGenerator implements TestSetGenerator<AnEnum> {
  @Override
  public SampleElements<AnEnum> samples() {
    return new Enums();
  }

 * generally be avoided. Prefer {@link Interners#newWeakInterner} or another {@code Interner}
 * implementation even for {@code String} interning.
 *
 * @author Kevin Bourrillion
 * @since 3.0
 */
@DoNotMock("Use Interners.new*Interner")
@J2ktIncompatible
@GwtIncompatible
public interface Interner<E> {
  /**

import com.google.common.base.Preconditions;
import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@link ImmutableSet} with exactly one element.
 *
 * @author Kevin Bourrillion
 * @author Nick Kralevich
 */
@GwtCompatible
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
final class SingletonImmutableSet<E> extends ImmutableSet<E> {

 * generally be avoided. Prefer {@link Interners#newWeakInterner} or another {@code Interner}
 * implementation even for {@code String} interning.
 *
 * @author Kevin Bourrillion
 * @since 3.0
 */
@DoNotMock("Use Interners.new*Interner")
@J2ktIncompatible
@GwtIncompatible
public interface Interner<E> {
  /**

import com.google.errorprone.annotations.DoNotMock;
import org.jspecify.annotations.NullMarked;

/**
 * Any object which can accept registrations of {@link TearDown} instances.
 *
 * @author Kevin Bourrillion
 * @since 10.0
 */
@DoNotMock("Implement with a lambda")
@GwtCompatible
@NullMarked
public interface TearDownAccepter {
  /**

/**
 * Suite of tests for OpenJdk 6 tests. The existence of this class is a hack because the
 * suitebuilder won't pick up the suites directly in the other classes because they don't extend
 * TestCase. Ergh.
 *
 * @author Kevin Bourrillion
 */
@AndroidIncompatible // test-suite builders
public class OpenJdk6Tests extends TestCase {
  public static Test suite() {
    TestSuite suite = new TestSuite();
    suite.addTest(OpenJdk6SetTests.suite());

import com.google.errorprone.annotations.DoNotMock;
import org.jspecify.annotations.NullMarked;

/**
 * Any object which can accept registrations of {@link TearDown} instances.
 *
 * @author Kevin Bourrillion
 * @since 10.0
 */
@DoNotMock("Implement with a lambda")
@GwtCompatible
@NullMarked
public interface TearDownAccepter {
  /**