@BeforeEach
  public void setUp() {
    commandLine = mock(CommandLine.class);
    parseResult = mock(CommandLine.ParseResult.class);
    CommandLine.Model.CommandSpec commandSpec = mock(CommandLine.Model.CommandSpec.class);
    optionSpec = mock(CommandLine.Model.OptionSpec.class);
    defaultValueProvider = mock(CommandLine.IDefaultValueProvider.class);
    when(commandLine.getParseResult()).thenReturn(parseResult);
    when(commandLine.getCommandSpec()).thenReturn(commandSpec);
    when(commandLine.getDefaultValueProvider()).thenReturn(defaultValueProvider);
    when(parseResult.matchedOptionValue(anyString(), any())).thenCallRealMethod();
    when(commandSpec.findOption(OPTION_NAME)).thenReturn(optionSpec);
  }
Unit tests for {@link CommandLineUtils} focusing on the retrieval of option values
(getOptionValueOrDefault).
app/src/test/java/org/hyperledger/besu/cli/CommandLineUtilsDefaultsTest.java