fix(serve): supplying help or version as an arg should throw

packages/serve/src/index.ts

@@ -28,9 +28,9 @@ export default function serve(...args: string[]): void {
         parsedWebpackArgs.unknownArgs
             .filter((e) => e)
             .forEach((unknown) => {
-                logger.warn('Unknown argument:', unknown);
+                logger.error('Unknown argument:', unknown);
             });
-        return;
+        process.exit(2);
     }
 
     cli.getCompiler(webpackArgs, core).then((compiler): void => {

test/help/help-commands.test.js

@@ -4,6 +4,17 @@ const { run } = require('../utils/test-utils');
 const helpHeader = 'The build tool for modern web applications';
 
 describe('commands help', () => {
+    it('throws error if supplied as an argument for subcommands', () => {
+        const { stderr } = run(__dirname, ['serve', 'help'], false);
+        expect(stderr).toContain('Unknown argument: help');
+    });
+
+    it('shows help information with subcommands as an arg', () => {
+        const { stdout, stderr } = run(__dirname, ['help', 'serve'], false);
+        expect(stdout).toContain('webpack s | serve');
+        expect(stderr).toHaveLength(0);
+    });
+
     it('throws error for invalid command with --help flag', () => {
         const { stderr } = run(__dirname, ['--help', 'myCommand'], false);
         expect(stderr).toContain(`You provided an invalid command 'myCommand'`);

test/serve/basic/serve-basic.test.js

@@ -1,11 +1,15 @@
 'use strict';
 
+const { yellow, options } = require('colorette');
 const path = require('path');
 const getPort = require('get-port');
 const { runServe } = require('../../utils/test-utils');
 
 const testPath = path.resolve(__dirname);
 
+const usageText = 'webpack s | serve';
+const descriptionText = 'Run the webpack Dev Server';
+
 describe('basic serve usage', () => {
     let port;
 
@@ -23,6 +27,14 @@ describe('basic serve usage', () => {
             console.warn('TODO: fix `serve` test on windows');
         });
     } else {
+        it('should respect the --no-color flag', async () => {
+            const { stdout, stderr } = await runServe(['--help', '--no-color'], __dirname);
+            options.enabled = true;
+            expect(stdout).not.toContain(yellow(usageText));
+            expect(stdout).toContain(descriptionText);
+            expect(stderr).toHaveLength(0);
+        });
+
         it('should not invoke info subcommand', async () => {
             const { stdout, stderr } = await runServe(['--client-log-level', 'info'], testPath);
             expect(stdout).toContain('main.js');