public void testConcat() {
    assertThat(Bytes.concat()).isEqualTo(EMPTY);
    assertThat(Bytes.concat(EMPTY)).isEqualTo(EMPTY);
    assertThat(Bytes.concat(EMPTY, EMPTY, EMPTY)).isEqualTo(EMPTY);
    assertThat(Bytes.concat(ARRAY1)).isEqualTo(ARRAY1);
    assertThat(Bytes.concat(ARRAY1)).isNotSameInstanceAs(ARRAY1);
    assertThat(Bytes.concat(EMPTY, ARRAY1, EMPTY)).isEqualTo(ARRAY1);
    assertThat(Bytes.concat(ARRAY1, ARRAY1, ARRAY1))

import static com.google.common.math.StatsTesting.ALL_MANY_VALUES;
import static com.google.common.math.StatsTesting.ALL_STATS;
import static com.google.common.math.StatsTesting.EMPTY_STATS_ITERABLE;
import static com.google.common.math.StatsTesting.EMPTY_STATS_VARARGS;
import static com.google.common.math.StatsTesting.INTEGER_MANY_VALUES;
import static com.google.common.math.StatsTesting.INTEGER_MANY_VALUES_COUNT;

   *
   * @param separatorPattern the pattern that determines whether a subsequence is a separator. This
   *     pattern may not match the empty string.
   * @return a splitter, with default settings, that uses this pattern
   * @throws IllegalArgumentException if {@code separatorPattern} matches the empty string
   */
  @GwtIncompatible // java.util.regex
  public static Splitter on(Pattern separatorPattern) {

import junit.framework.TestCase;

/**
 * {@link LoadingCache} tests that deal with empty caches.
 *
 * @author mike nonemacher
 */

public class EmptyCachesTest extends TestCase {

  public void testEmpty() {
    for (LoadingCache<Object, Object> cache : caches()) {
      checkEmpty(cache);
    }
  }


  public void testInvalidate_empty() {
    for (LoadingCache<Object, Object> cache : caches()) {

      }
    } catch (NoSuchElementException e) {
      throw new IllegalArgumentException(e);
    }

    boolean empty;
    if (effectiveRange.isEmpty()) {
      empty = true;
    } else {
      /*
       * requireNonNull is safe because the effectiveRange operations above would have thrown or
       * effectiveRange.isEmpty() would have returned true.
       */

    expectContents();
  }

  // retainAll(null)

  /*
   * AbstractCollection fails the retainAll(null) test when the subject
   * collection is empty, but we'd still like to test retainAll(null) when we
   * can. We split the test into empty and non-empty cases. This allows us to
   * suppress only the former.
   */

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)

  }

  @GwtIncompatible // ObjectArrays.newArray(Class, int)
  public void testNewArray_fromClass_Empty() {
    String[] empty = ObjectArrays.newArray(String.class, 0);
    assertEquals(String[].class, empty.getClass());
    assertThat(empty).isEmpty();
  }

  @GwtIncompatible // ObjectArrays.newArray(Class, int)
  public void testNewArray_fromClass_Nonempty() {

        if (title == null) {
            return StringUtil.EMPTY; // empty
        }

        final int[] spaceChars = getSpaceChars();
        try (final Reader reader = new StringReader(title)) {
            return TextUtil.normalizeText(reader).initialCapacity(title.length()).spaceChars(spaceChars).execute();
        } catch (final IOException e) {
            return StringUtil.EMPTY; // empty
        }
    }

func (b *Buffer) String() string {
	if b == nil {
		// Special case, useful in debugging.
		return "<nil>"
	}
	return string(b.buf[b.off:])
}

// empty reports whether the unread portion of the buffer is empty.
func (b *Buffer) empty() bool { return len(b.buf) <= b.off }

// Len returns the number of bytes of the unread portion of the buffer;
// b.Len() == len(b.Bytes()).

     *            empty.
     * @param pluginArtifactId The artifact id of the plugin whose configuration should be used, must not be
     *            {@code null} or empty.
     * @param pluginExecutionId The id of a plugin execution whose configuration should be used, may be {@code null} or
     *            empty to use the general plugin configuration.