@Test
  public void testGetOptionValueOrDefault_DefaultValue() throws Exception {
    when(defaultValueProvider.defaultValue(optionSpec)).thenReturn(DEFAULT_VALUE);
    String result = getOptionValueOrDefault(commandLine, OPTION_NAME, converter);
    assertThat(result).isEqualTo(DEFAULT_VALUE);
  }
Unit tests for {@link CommandLineUtils} focusing on the retrieval of option values
(getOptionValueOrDefault).
app/src/test/java/org/hyperledger/besu/cli/CommandLineUtilsDefaultsTest.java