return map.containsKey(o);
    }

    @Override
    public boolean add(final String o) {
        return map.put(o, PRESENT) == null;
    }

    @Override
    public boolean remove(final Object o) {
        return map.remove(o) == PRESENT;
    }

    @Override
    public void clear() {
        map.clear();
    }

  @CollectionSize.Require(absent = ZERO)
  public void testRemove_present() {
    int initialSize = collection.size();
    assertTrue("remove(present) should return true", collection.remove(e0()));
    assertEquals(
        "remove(present) should decrease a collection's size by one.",
        initialSize - 1,
        collection.size());
    expectMissing(e0());
  }

    @ParameterizedTest(name = "session error {1} -\\u003e {2}")
    @CsvSource({ "-1,Connection refused", "0x80,Not listening on called name", "0x81,Not listening for calling name",
            "0x82,Called name not present", "0x83,Called name present, but insufficient resources", "0x8F,Unspecified error",
            "999,Unknown error code: 999" })
    @DisplayName("getErrorString for SSN service errors")

        }
    }

    @Test
    @DisplayName("Messages: array is present and contains expected first entries")
    void dosErrorMessagesContainsExpectedTexts() {
        // Arrange & Act
        String[] msgs = DosError.DOS_ERROR_MESSAGES;

        // Assert
        assertNotNull(msgs);
        assertTrue(msgs.length >= 3, "Expect at least the first 3 entries present");
        assertEquals("The operation completed successfully.", msgs[0]);

                break;
            case CALLED_NOT_PRESENT:
                result.append("Called name not present");
                break;
            case NO_RESOURCES:
                result.append("Called name present, but insufficient resources");
                break;
            case UNSPECIFIED:
                result.append("Unspecified error");
                break;

		}
		if err == nil && test.ShouldFail {
			t.Fatalf("Test %d: should have failed but succeeded", i)
		}

		if !test.ShouldFail && ok != test.IsPresent {
			t.Fatalf("Test %d: reported that KMS present=%v - want present=%v", i, ok, test.IsPresent)
		}
	}
}

var isPresentTests = []struct {
	Env        map[string]string
	IsPresent  bool
	ShouldFail bool
}{
	{Env: map[string]string{}}, // 0
	{ // 1

                        "Event types " + events[i] + " and " + events[j] + " have the same value");
            }
        }
    }

    @Test
    void testWitnessRegistrationStates() {
        assertEquals(5, WitnessRegistration.WitnessRegistrationState.values().length);

        // Verify all expected states are present

			if nodeName == "" {
				nodeName = addr
			}
			if endpoint.IsLocal {
				// Only proceed for local endpoints
				network[nodeName] = string(madmin.ItemOnline)
				continue
			}
			_, present := network[nodeName]
			if !present {
				if err := isServerResolvable(endpoint, 5*time.Second); err == nil {
					network[nodeName] = string(madmin.ItemOnline)
				} else {
					if xnet.IsNetworkOrHostDown(err, false) {

  public void testGetOrDefault_present() {
    assertEquals(
        "getOrDefault(present, def) should return the associated value",
        v0(),
        getMap().getOrDefault(k0(), v3()));
  }

  @CollectionSize.Require(absent = ZERO)
  public void testGetOrDefault_presentNullDefault() {
    assertEquals(
        "getOrDefault(present, null) should return the associated value",
        v0(),

    implements ListeningExecutorService {
  /** Constructor for use by subclasses. */
  public AbstractListeningExecutorService() {}

  /**
   * @since 19.0 (present with return type {@code ListenableFutureTask} since 14.0)
   */
  @CanIgnoreReturnValue // TODO(kak): consider removing this
  @Override
  protected final <T extends @Nullable Object> RunnableFuture<T> newTaskFor(