feat: show command usage on exception (#414)

Author: renancaraujo

lib/src/command_runner.dart

@@ -89,7 +89,7 @@ class VeryGoodCommandRunner extends CommandRunner<int> {
       _logger
         ..err(e.message)
         ..info('')
-        ..info(usage);
+        ..info(e.usage);
       return ExitCode.usage.code;
     }
   }

lib/src/commands/create/create.dart

@@ -207,25 +207,23 @@ class CreateCommand extends Command<int> {
   void _validateOrgName(String name) {
     final isValidOrgName = _isValidOrgName(name);
     if (!isValidOrgName) {
-      throw UsageException(
+      usageException(
         '"$name" is not a valid org name.\n\n'
         'A valid org name has at least 2 parts separated by "."\n'
         'Each part must start with a letter and only include '
         'alphanumeric characters (A-Z, a-z, 0-9), underscores (_), '
         'and hyphens (-)\n'
         '(ex. very.good.org)',
-        usage,
       );
     }
   }
 
   void _validateProjectName(String name) {
     final isValidProjectName = _isValidPackageName(name);
     if (!isValidProjectName) {
-      throw UsageException(
+      usageException(
         '"$name" is not a valid package name.\n\n'
         'See https://dart.dev/tools/pub/pubspec#name for more information.',
-        usage,
       );
     }
   }
@@ -247,14 +245,11 @@ class CreateCommand extends Command<int> {
 
   void _validateOutputDirectoryArg(List<String> args) {
     if (args.isEmpty) {
-      throw UsageException(
-        'No option specified for the output directory.',
-        usage,
-      );
+      usageException('No option specified for the output directory.');
     }
 
     if (args.length > 1) {
-      throw UsageException('Multiple output directories specified.', usage);
+      usageException('Multiple output directories specified.');
     }
   }
 }

lib/src/commands/packages.dart

@@ -53,7 +53,7 @@ class PackagesGetCommand extends Command<int> {
   @override
   Future<int> run() async {
     if (_argResults.rest.length > 1) {
-      throw UsageException('Too many arguments', usage);
+      usageException('Too many arguments');
     }
 
     final recursive = _argResults['recursive'] as bool;

test/src/command_runner_test.dart

@@ -147,7 +147,7 @@ void main() {
       });
 
       test('handles UsageException', () async {
-        final exception = UsageException('oops!', commandRunner.usage);
+        final exception = UsageException('oops!', 'exception usage');
         var isFirstInvocation = true;
         when(() => logger.info(any())).thenAnswer((_) {
           if (isFirstInvocation) {
@@ -158,7 +158,7 @@ void main() {
         final result = await commandRunner.run(['--version']);
         expect(result, equals(ExitCode.usage.code));
         verify(() => logger.err(exception.message)).called(1);
-        verify(() => logger.info(commandRunner.usage)).called(1);
+        verify(() => logger.info('exception usage')).called(1);
       });
 
       test(