}
        if (username.length() > MAX_USERNAME_LENGTH) {
            throw new IllegalArgumentException("Username exceeds maximum length: " + username.length());
        }
        if (!username.isEmpty() && !VALID_USERNAME.matcher(username).matches()) {
            throw new IllegalArgumentException("Username contains invalid characters: " + username);
        }
    }

    /**
     * Validates domain name

 *
 * @author Colin Decker
 */
@GwtCompatible
final class GoogleHelpers {

  private GoogleHelpers() {}

  static void assertEmpty(Multimap<?, ?> multimap) {
    if (!multimap.isEmpty()) {
      fail("Not true that " + multimap + " is empty");
    }
  }

                traverseTest(new RestTestContext(testName), test, null, objectKeyFinders, arrayByObjectKeyFinders);
            }
        }

        // transform the global setup
        if (setupTransforms.isEmpty() == false) {
            int i = 0;
            for (RestTestTransformGlobalSetup setupTransform : setupTransforms) {
                ObjectNode result = setupTransform.transformSetup(setupSection);

                return "[]";
            }
        };

        List<Artifact> result = testHelper.loadArtifactsFromRepository("test.yaml");
        assertNotNull(result);
        assertTrue(result.isEmpty());
    }

    @Test
    public void test_loadArtifactsFromRepository_nullResult() {
        PluginHelper testHelper = new PluginHelper() {
            @Override

    GeneralRange<Integer> range = GeneralRange.range(ORDERING, 2, OPEN, 4, CLOSED);
    assertTrue(range.intersect(GeneralRange.range(ORDERING, 5, CLOSED, 6, CLOSED)).isEmpty());
    assertTrue(range.intersect(GeneralRange.range(ORDERING, 1, OPEN, 2, OPEN)).isEmpty());
  }

  public void testFromRangeAll() {
    assertEquals(GeneralRange.all(Ordering.natural()), GeneralRange.from(Range.all()));
  }

      return new StandardElementSet();
    }

    @Override
    public Iterator<T> iterator() {
      return standardIterator();
    }

    @Override
    public boolean isEmpty() {
      return standardIsEmpty();
    }

    @Override
    public int size() {
      return standardSize();
    }
  }

  @AndroidIncompatible // test-suite builders

        for (int c : WinError.WINERR_CODES) {
            assertNotEquals(unknownCode, c, "Chosen unknown code unexpectedly clashes with a known code");
        }
        assertTrue(lookupMessage(unknownCode).isEmpty());
    }

    @Test
    @DisplayName("Codes: all non-negative and unique")
    void codes_are_non_negative_and_unique() {
        // Edge checks: ensure there are no negative or duplicate codes

            System.err.println("Usage: java FindCommits.java <target_branch_name>");
            System.exit(2);
        }

        String targetBranch = args[0].trim();
        if (targetBranch.isEmpty()) {
            System.err.println("target_branch_name must not be empty");
            System.exit(2);
        }

        String targetRef = "refs/remotes/origin/" + targetBranch;

        if (entry.getKey().equals(key)) {
          expectedValues.add(entry.getValue());
        }
      }

      Collection<V> collection = multimap().asMap().get(key);
      if (expectedValues.isEmpty()) {
        assertNull(collection);
      } else {
        assertEqualIgnoringOrder(expectedValues, collection);
      }
    }
  }

  @CollectionSize.Require(absent = ZERO)

 */
@GwtCompatible
abstract class AbstractMultiset<E extends @Nullable Object> extends AbstractCollection<E>
    implements Multiset<E> {
  // Query Operations

  @Override
  public boolean isEmpty() {
    return entrySet().isEmpty();
  }

  @Override
  public boolean contains(@Nullable Object element) {
    return count(element) > 0;
  }

  // Modification Operations
  @CanIgnoreReturnValue
  @Override