@Override
  Collection<Integer> createUnfiltered(Iterable<Integer> contents) {
    return Lists.newArrayList(contents);
  }

  @Override
  Collection<Integer> filter(Collection<Integer> elements, Predicate<? super Integer> predicate) {
    return Collections2.filter(elements, predicate);
  }

  @Override
  Set<Integer> createUnfiltered(Iterable<Integer> contents) {
    return Sets.newHashSet(contents);
  }

  @Override
  Set<Integer> filter(Set<Integer> elements, Predicate<? super Integer> predicate) {
    return Sets.filter(elements, predicate);
  }

    Multimap<String, Integer> filtered = Multimaps.filterValues(keyFiltered, VALUE_PREDICATE);
    assertEquals(1, filtered.size());
    assertTrue(filtered.containsEntry("foo", 1));
    assertTrue(filtered.keySet().retainAll(Arrays.asList("cat", "dog")));
    assertEquals(0, filtered.size());
  }

  // TODO(jlevy): Many more tests needed.

    assertEquals("gz", Files.getFileExtension("blah.tar.gz"));
    assertEquals("", Files.getFileExtension("/"));
    assertEquals("", Files.getFileExtension("."));
    assertEquals("", Files.getFileExtension(".."));
    assertEquals("", Files.getFileExtension("..."));
    assertEquals("", Files.getFileExtension("blah"));
    assertEquals("", Files.getFileExtension("blah."));
    assertEquals("", Files.getFileExtension(".blah."));

        FileOutputStream out = new FileOutputStream(file);
        try {
          out.write(initialBytes);
        } finally {
          out.close();
        }
        return Files.asByteSink(file, FileWriteMode.APPEND);
      }
      return Files.asByteSink(file);
    }

    @Override
    public byte[] getExpected(byte[] bytes) {
      if (initialBytes == null) {
        return checkNotNull(bytes);
      } else {

/**
 * Unit test for {@link Files#createTempDir}.
 *
 * @author Chris Nokleberg
 */

@SuppressWarnings("deprecation") // tests of a deprecated method
public class FilesCreateTempDirTest extends TestCase {
  public void testCreateTempDir() throws IOException {
    if (JAVA_IO_TMPDIR.value().equals("/sdcard")) {
      assertThrows(IllegalStateException.class, Files::createTempDir);
      return;
    }

    util.concurrent tests under Guava.

    The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see https://goo.gl/pRV3Yn for details.

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one
    for prod and one for tests. However, unlike our other packages, as of this

   * the given class. If the object being tested is {@code null} this predicate evaluates to {@code
   * false}.
   *
   * <p>If you want to filter an {@code Iterable} to narrow its type, consider using {@link
   * com.google.common.collect.Iterables#filter(Iterable, Class)} in preference.
   *
   * <p><b>Warning:</b> contrary to the typical assumptions about predicates (as documented at

The modules under this directory will be released exactly once each. Once that

 * relevant methods below.
 *
 * <ul>
 *   <li>This class is serializable; {@code java.util.Optional} is not.
 *   <li>{@code java.util.Optional} has the additional methods {@code ifPresent}, {@code filter},
 *       {@code flatMap}, and {@code orElseThrow}.
 *   <li>{@code java.util} offers the primitive-specialized versions {@code OptionalInt}, {@code