feat: add form validation test scenarios

tests/form-validation.spec.ts

@@ -0,0 +1,52 @@
+import { test, expect } from '@playwright/test';
+
+test.describe('Form validation', () => {
+
+    test.beforeEach(async ({ page }) => {
+        await page.goto('https://demo.playwright.dev/todomvc');
+    });
+
+    test('should show error when required field is empty', async ({ page }) => {
+        const input = page.getByPlaceholder('What needs to be done?');
+        await input.click();
+        await input.press('Enter');
+        const items = page.getByTestId('todo-item');
+        await expect(items).toHaveCount(0);
+    });
+
+    test('should not accept whitespace-only input', async ({ page }) => {
+        const input = page.getByPlaceholder('What needs to be done?');
+        await input.fill('     ');
+        await input.press('Enter');
+        const items = page.getByTestId('todo-item');
+        await expect(items).toHaveCount(0);
+    });
+
+    test('should accept valid input and add item', async ({ page }) => {
+        const input = page.getByPlaceholder('What needs to be done?');
+        await input.fill('Buy groceries');
+        await input.press('Enter');
+        const items = page.getByTestId('todo-item');
+        await expect(items).toHaveCount(1);
+        await expect(items.first()).toContainText('Buy groceries');
+    });
+
+    test('should clear input field after valid submission', async ({ page }) => {
+        const input = page.getByPlaceholder('What needs to be done?');
+        await input.fill('Walk the dog');
+        await input.press('Enter');
+        await expect(input).toHaveValue('');
+    });
+
+    test('should allow adding multiple valid items', async ({ page }) => {
+        const input = page.getByPlaceholder('What needs to be done?');
+        const todos = ['Buy milk', 'Read a book', 'Go for a run'];
+        for (const todo of todos) {
+            await input.fill(todo);
+            await input.press('Enter');
+        }
+        const items = page.getByTestId('todo-item');
+        await expect(items).toHaveCount(3);
+    });
+
+});