test: Add "smoke test" that all sub-modules can be loaded.

Before the test suite failed to catch a failure that would be obvious
to a user that the "--help" command doesn't work, because no test
checked simply that all modules could be loaded, which --help
happens to do.

Author: markstos

test/cli-smoke.test.js

@@ -0,0 +1,31 @@
+import {describe, test} from 'node:test';
+import assert from 'node:assert/strict';
+import {execFile} from 'node:child_process';
+import {fileURLToPath} from 'node:url';
+import {dirname, join} from 'node:path';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const cliPath = join(__dirname, '..', 'bin', 'cli.js');
+
+function runCLI(args) {
+    return new Promise((resolve) => {
+        execFile('node', [cliPath, ...args], {timeout: 10000}, (error, stdout, stderr) => {
+            resolve({
+                exitCode: error ? error.code : 0,
+                stdout,
+                stderr
+            });
+        });
+    });
+}
+
+describe('CLI smoke test', function () {
+    test('--help loads all commands without errors', async function () {
+        const result = await runCLI(['--help']);
+
+        assert.strictEqual(result.exitCode, 0, `CLI exited with code ${result.exitCode}.\nstderr: ${result.stderr}`);
+        assert.strictEqual(result.stderr, '', `Unexpected stderr output: ${result.stderr}`);
+        assert.ok(result.stdout.includes('Commands:') || result.stdout.includes('Usage:'),
+            'Expected help output to contain usage information');
+    });
+});