fix(dart_frog_cli): handle UsageException when invalid option is passed (#399)

Author: Ascenio

packages/dart_frog_cli/lib/src/command_runner.dart

@@ -50,11 +50,17 @@ class DartFrogCommandRunner extends CommandRunner<int> {
 
   @override
   Future<int> run(Iterable<String> args) async {
-    final argResults = parse(args);
-    late final int exitCode;
+    late final ArgResults argResults;
+    try {
+      argResults = parse(args);
+    } on UsageException catch (error) {
+      _logger.err('$error');
+      return ExitCode.usage.code;
+    }
 
     _sigint.watch().listen(_onSigint);
 
+    late final int exitCode;
     try {
       exitCode = await runCommand(argResults) ?? ExitCode.success.code;
     } catch (error) {

packages/dart_frog_cli/test/src/command_runner_test.dart

@@ -82,6 +82,26 @@ void main() {
     });
 
     group('run', () {
+      test('shows usage when invalid option is passed', () async {
+        final exitCode = await commandRunner.run(['--invalid-option']);
+        expect(exitCode, ExitCode.usage.code);
+        verify(
+          () => logger.err(
+            any(
+              that: predicate<String>((message) {
+                final containsError = message.contains(
+                  'Could not find an option named "invalid-option".',
+                );
+                final containsUsage = message.contains(
+                  'Usage: dart_frog <command> [arguments]',
+                );
+                return containsError && containsUsage;
+              }),
+            ),
+          ),
+        ).called(1);
+      });
+
       test('checks for updates on sigint', () async {
         final exitCalls = <int>[];
         commandRunner = DartFrogCommandRunner(