public String getUuid() {
    return toString();
  }
@Test
  public void uuidDoesNotChangeBetweenRuns() {
    // Given
    Uuid uuid = new Uuid();

    // When
    String firstUuid = uuid.getUuid();
    String secondUuid = uuid.getUuid();

    // Then
    assertEquals(secondUuid, firstUuid);
  }