@Test
public void generateCredential_usesAppropriateGenerationParameters() {

  final ArgumentCaptor<StringGenerationParameters> captor = ArgumentCaptor.forClass(StringGenerationParameters.class);
  subject.generateCredential();
  verify(passayStringCredentialGenerator, times(1))
    .generateCredential(captor.capture());
  final StringGenerationParameters actual = captor.getValue();
  assertThat(actual.getLength(), equalTo(20));
  assertThat(actual.isExcludeLower(), equalTo(false));
  assertThat(actual.isExcludeUpper(), equalTo(false));
  assertThat(actual.isExcludeNumber(), equalTo(true));
  assertThat(actual.isIncludeSpecial(), equalTo(false));
}