tests: add test for --watch flag (#1854)

* tests: add test for --watch flag

Author: snitin315

test/watch/main.js

@@ -0,0 +1 @@
+console.log('watch flag test');

test/watch/watch-flag.test.js

@@ -0,0 +1,23 @@
+'use strict';
+
+const { runWatch, isWindows } = require('../utils/test-utils');
+
+describe('--watch flag', () => {
+    if (isWindows) {
+        it('TODO: Fix on windows', () => {
+            expect(true).toBe(true);
+        });
+        return;
+    }
+
+    it('should watch for file changes', async () => {
+        const { stdout } = await runWatch({
+            testCase: __dirname,
+            args: ['--watch'],
+            setOutput: false,
+            outputKillStr: 'main',
+        });
+
+        expect(stdout).toContain('watching files for updates...');
+    });
+});