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

    DetailsSupplier detailsSupplier = readDetailsSupplier(underTest);

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