public MyNewIssuesNotification newMyNewIssuesNotification(Map<String, UserDto> assigneesByUuid) {
    verifyAssigneesByUuid(assigneesByUuid);
    return new MyNewIssuesNotification(new DetailsSupplierImpl(assigneesByUuid));
  }
@Test
  public void newMyNewIssuesNotification_DetailsSupplier_getUserNameByUuid_fails_with_NPE_if_uuid_is_null() {
    MyNewIssuesNotification underTest = this.underTest.newMyNewIssuesNotification(emptyMap());

    DetailsSupplier detailsSupplier = readDetailsSupplier(underTest);

    assertThatThrownBy(() -> detailsSupplier.getUserNameByUuid(null))
      .isInstanceOf(NullPointerException.class)
      .hasMessage("uuid can't be null");
  }