Added basic playwright config. Next up, trialing login page

UI/Web/.gitignore

@@ -2,3 +2,6 @@ node_modules/
 test-results/
 playwright-report/
 i18n-cache-busting.json
+/playwright-report/
+/blob-report/
+/playwright/.cache/

UI/Web/e2e-tests/example.spec.ts

@@ -0,0 +1,18 @@
+import { test, expect } from '@playwright/test';
+
+test('has title', async ({ page }) => {
+  await page.goto('https://playwright.dev/');
+
+  // Expect a title "to contain" a substring.
+  await expect(page).toHaveTitle(/Playwright/);
+});
+
+test('get started link', async ({ page }) => {
+  await page.goto('https://playwright.dev/');
+
+  // Click the get started link.
+  await page.getByRole('link', { name: 'Get started' }).click();
+
+  // Expects page to have a heading with the name of Installation.
+  await expect(page.getByRole('heading', { name: 'Installation' })).toBeVisible();
+});

UI/Web/package-lock.json

@@ -60,6 +60,7 @@
         "@angular/build": "^18.2.10",
         "@angular/cli": "^18.2.10",
         "@angular/compiler-cli": "^18.2.9",
+        "@playwright/test": "^1.49.0",
         "@types/d3": "^7.4.3",
         "@types/file-saver": "^2.0.7",
         "@types/luxon": "^3.4.0",
@@ -464,7 +465,6 @@
       "version": "18.2.9",
       "resolved": "https://registry.npmjs.org/@angular/compiler-cli/-/compiler-cli-18.2.9.tgz",
       "integrity": "sha512-4iMoRvyMmq/fdI/4Gob9HKjL/jvTlCjbS4kouAYHuGO9w9dmUhi1pY1z+mALtCEl9/Q8CzU2W8e5cU2xtV4nVg==",
-      "dev": true,
       "dependencies": {
         "@babel/core": "7.25.2",
         "@jridgewell/sourcemap-codec": "^1.4.14",
@@ -492,7 +492,6 @@
       "version": "4.0.1",
       "resolved": "https://registry.npmjs.org/chokidar/-/chokidar-4.0.1.tgz",
       "integrity": "sha512-n8enUVCED/KVRQlab1hr3MVpcVMvxtZjmEa956u+4YijlmQED223XMSYj2tLuKvr4jcCTzNNMpQDUer72MMmzA==",
-      "dev": true,
       "dependencies": {
         "readdirp": "^4.0.1"
       },
@@ -507,7 +506,6 @@
       "version": "4.0.2",
       "resolved": "https://registry.npmjs.org/readdirp/-/readdirp-4.0.2.tgz",
       "integrity": "sha512-yDMz9g+VaZkqBYS/ozoBJwaBhTbZo3UNYQHNRw1D3UFQB8oHB4uS/tAODO+ZLjGWmUbKnIlOWO+aaIiAxrUWHA==",
-      "dev": true,
       "engines": {
         "node": ">= 14.16.0"
       },
@@ -2461,6 +2459,21 @@
         "node": ">=14"
       }
     },
+    "node_modules/@playwright/test": {
+      "version": "1.49.0",
+      "resolved": "https://registry.npmjs.org/@playwright/test/-/test-1.49.0.tgz",
+      "integrity": "sha512-DMulbwQURa8rNIQrf94+jPJQ4FmOVdpE5ZppRNvWVjvhC+6sOeo28r8MgIpQRYouXRtt/FCCXU7zn20jnHR4Qw==",
+      "dev": true,
+      "dependencies": {
+        "playwright": "1.49.0"
+      },
+      "bin": {
+        "playwright": "cli.js"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
     "node_modules/@polka/url": {
       "version": "1.0.0-next.25",
       "resolved": "https://registry.npmjs.org/@polka/url/-/url-1.0.0-next.25.tgz",
@@ -4010,8 +4023,7 @@
     "node_modules/convert-source-map": {
       "version": "1.9.0",
       "resolved": "https://registry.npmjs.org/convert-source-map/-/convert-source-map-1.9.0.tgz",
-      "integrity": "sha512-ASFBup0Mz1uyiIjANan1jzLQami9z1PoYSZCiiYW2FczPbenXc45FZdBZLzOT+r6+iciuEModtmCti+hjaAk0A==",
+      "integrity": "sha512-ASFBup0Mz1uyiIjANan1jzLQami9z1PoYSZCiiYW2FczPbenXc45FZdBZLzOT+r6+iciuEModtmCti+hjaAk0A=="
-      "dev": true
     },
     "node_modules/cosmiconfig": {
       "version": "8.3.6",
@@ -4518,7 +4530,6 @@
       "version": "0.1.13",
       "resolved": "https://registry.npmjs.org/encoding/-/encoding-0.1.13.tgz",
       "integrity": "sha512-ETBauow1T35Y/WZMkio9jiM0Z5xjHHmJ4XmjZOq1l/dXz3lr2sRn87nJy20RupqSh1F2m3HHPSp8ShIPQJrJ3A==",
-      "dev": true,
       "optional": true,
       "dependencies": {
         "iconv-lite": "^0.6.2"
@@ -4528,7 +4539,6 @@
       "version": "0.6.3",
       "resolved": "https://registry.npmjs.org/iconv-lite/-/iconv-lite-0.6.3.tgz",
       "integrity": "sha512-4fCk79wshMdzMp2rH06qWrJE4iolqLhCUH+OiuIgU++RB0+94NlDL81atO7GX55uUKueo0txHNtvEyI6D7WdMw==",
-      "dev": true,
       "optional": true,
       "dependencies": {
         "safer-buffer": ">= 2.1.2 < 3.0.0"
@@ -7322,6 +7332,50 @@
         "nice-napi": "^1.0.2"
       }
     },
+    "node_modules/playwright": {
+      "version": "1.49.0",
+      "resolved": "https://registry.npmjs.org/playwright/-/playwright-1.49.0.tgz",
+      "integrity": "sha512-eKpmys0UFDnfNb3vfsf8Vx2LEOtflgRebl0Im2eQQnYMA4Aqd+Zw8bEOB+7ZKvN76901mRnqdsiOGKxzVTbi7A==",
+      "dev": true,
+      "dependencies": {
+        "playwright-core": "1.49.0"
+      },
+      "bin": {
+        "playwright": "cli.js"
+      },
+      "engines": {
+        "node": ">=18"
+      },
+      "optionalDependencies": {
+        "fsevents": "2.3.2"
+      }
+    },
+    "node_modules/playwright-core": {
+      "version": "1.49.0",
+      "resolved": "https://registry.npmjs.org/playwright-core/-/playwright-core-1.49.0.tgz",
+      "integrity": "sha512-R+3KKTQF3npy5GTiKH/T+kdhoJfJojjHESR1YEWhYuEKRVfVaxH3+4+GvXE5xyCngCxhxnykk0Vlah9v8fs3jA==",
+      "dev": true,
+      "bin": {
+        "playwright-core": "cli.js"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/playwright/node_modules/fsevents": {
+      "version": "2.3.2",
+      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz",
+      "integrity": "sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==",
+      "dev": true,
+      "hasInstallScript": true,
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "engines": {
+        "node": "^8.16.0 || ^10.6.0 || >=11.0.0"
+      }
+    },
     "node_modules/postcss": {
       "version": "8.4.41",
       "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.4.41.tgz",
@@ -7470,8 +7524,7 @@
     "node_modules/reflect-metadata": {
       "version": "0.2.2",
       "resolved": "https://registry.npmjs.org/reflect-metadata/-/reflect-metadata-0.2.2.tgz",
-      "integrity": "sha512-urBwgfrvVP/eAyXx4hluJivBKzuEbSQs9rKWCrCkbSxNv8mxPcUZKeuoF3Uy4mJl3Lwprp6yy5/39VWigZ4K6Q==",
+      "integrity": "sha512-urBwgfrvVP/eAyXx4hluJivBKzuEbSQs9rKWCrCkbSxNv8mxPcUZKeuoF3Uy4mJl3Lwprp6yy5/39VWigZ4K6Q=="
-      "dev": true
     },
     "node_modules/replace-in-file": {
       "version": "7.1.0",
@@ -7742,7 +7795,7 @@
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/safer-buffer/-/safer-buffer-2.1.2.tgz",
       "integrity": "sha512-YZo3K82SD7Riyi0E1EQPojLz7kpepnSQI9IyPbHHg1XXXevb5dJI7tpyN2ADxGcQbHG7vcyRHk0cbwqcQriUtg==",
-      "dev": true
+      "devOptional": true
     },
     "node_modules/sass": {
       "version": "1.77.6",
@@ -7776,7 +7829,6 @@
       "version": "7.6.3",
       "resolved": "https://registry.npmjs.org/semver/-/semver-7.6.3.tgz",
       "integrity": "sha512-oVekP1cKtI+CTDvHWYFUcMtsK/00wmAEfyqKfNdARm8u1wNVhSgaX7A8d4UuIlUI5e84iEwOhs7ZPYRmzU9U6A==",
-      "dev": true,
       "bin": {
         "semver": "bin/semver.js"
       },
@@ -8331,7 +8383,6 @@
       "version": "5.5.4",
       "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.5.4.tgz",
       "integrity": "sha512-Mtq29sKDAEYP7aljRgtPOpTvOfbwRWlS6dPRzwjdE+C0R4brX/GUyhHSecbHMFLNBLcJIPt9nl9yG5TZ1weH+Q==",
-      "dev": true,
       "bin": {
         "tsc": "bin/tsc",
         "tsserver": "bin/tsserver"

UI/Web/package.json

@@ -12,7 +12,7 @@
     "prod": "npm run cache-locale-prime && ng build --configuration production && npm run minify-langs && npm run cache-locale",
     "explore": "ng build --stats-json && webpack-bundle-analyzer dist/stats.json",
     "lint": "ng lint",
-    "e2e": "ng e2e"
+    "e2e": "npx playwright test --ui"
   },
   "private": true,
   "dependencies": {
@@ -68,6 +68,7 @@
     "@angular/build": "^18.2.10",
     "@angular/cli": "^18.2.10",
     "@angular/compiler-cli": "^18.2.9",
+    "@playwright/test": "^1.49.0",
     "@types/d3": "^7.4.3",
     "@types/file-saver": "^2.0.7",
     "@types/luxon": "^3.4.0",

UI/Web/playwright.config.ts

@@ -0,0 +1,79 @@
+import { defineConfig, devices } from '@playwright/test';
+
+/**
+ * Read environment variables from file.
+ * https://github.com/motdotla/dotenv
+ */
+// import dotenv from 'dotenv';
+// import path from 'path';
+// dotenv.config({ path: path.resolve(__dirname, '.env') });
+
+/**
+ * See https://playwright.dev/docs/test-configuration.
+ */
+export default defineConfig({
+  testDir: './e2e-tests',
+  /* Run tests in files in parallel */
+  fullyParallel: true,
+  /* Fail the build on CI if you accidentally left test.only in the source code. */
+  forbidOnly: !!process.env.CI,
+  /* Retry on CI only */
+  retries: process.env.CI ? 2 : 0,
+  /* Opt out of parallel tests on CI. */
+  workers: process.env.CI ? 1 : undefined,
+  /* Reporter to use. See https://playwright.dev/docs/test-reporters */
+  reporter: 'html',
+  /* Shared settings for all the projects below. See https://playwright.dev/docs/api/class-testoptions. */
+  use: {
+    /* Base URL to use in actions like `await page.goto('/')`. */
+    // baseURL: 'http://127.0.0.1:3000',
+
+    /* Collect trace when retrying the failed test. See https://playwright.dev/docs/trace-viewer */
+    trace: 'on-first-retry',
+  },
+
+  /* Configure projects for major browsers */
+  projects: [
+    {
+      name: 'chromium',
+      use: { ...devices['Desktop Chrome'] },
+    },
+
+    {
+      name: 'firefox',
+      use: { ...devices['Desktop Firefox'] },
+    },
+
+    {
+      name: 'webkit',
+      use: { ...devices['Desktop Safari'] },
+    },
+
+    /* Test against mobile viewports. */
+    // {
+    //   name: 'Mobile Chrome',
+    //   use: { ...devices['Pixel 5'] },
+    // },
+    // {
+    //   name: 'Mobile Safari',
+    //   use: { ...devices['iPhone 12'] },
+    // },
+
+    /* Test against branded browsers. */
+    // {
+    //   name: 'Microsoft Edge',
+    //   use: { ...devices['Desktop Edge'], channel: 'msedge' },
+    // },
+    // {
+    //   name: 'Google Chrome',
+    //   use: { ...devices['Desktop Chrome'], channel: 'chrome' },
+    // },
+  ],
+
+  /* Run your local dev server before starting the tests */
+  // webServer: {
+  //   command: 'npm run start',
+  //   url: 'http://127.0.0.1:3000',
+  //   reuseExistingServer: !process.env.CI,
+  // },
+});

UI/Web/tests-examples/demo-todo-app.spec.ts

@@ -0,0 +1,437 @@
+import { test, expect, type Page } from '@playwright/test';
+
+test.beforeEach(async ({ page }) => {
+  await page.goto('https://demo.playwright.dev/todomvc');
+});
+
+const TODO_ITEMS = [
+  'buy some cheese',
+  'feed the cat',
+  'book a doctors appointment'
+] as const;
+
+test.describe('New Todo', () => {
+  test('should allow me to add todo items', async ({ page }) => {
+    // create a new todo locator
+    const newTodo = page.getByPlaceholder('What needs to be done?');
+
+    // Create 1st todo.
+    await newTodo.fill(TODO_ITEMS[0]);
+    await newTodo.press('Enter');
+
+    // Make sure the list only has one todo item.
+    await expect(page.getByTestId('todo-title')).toHaveText([
+      TODO_ITEMS[0]
+    ]);
+
+    // Create 2nd todo.
+    await newTodo.fill(TODO_ITEMS[1]);
+    await newTodo.press('Enter');
+
+    // Make sure the list now has two todo items.
+    await expect(page.getByTestId('todo-title')).toHaveText([
+      TODO_ITEMS[0],
+      TODO_ITEMS[1]
+    ]);
+
+    await checkNumberOfTodosInLocalStorage(page, 2);
+  });
+
+  test('should clear text input field when an item is added', async ({ page }) => {
+    // create a new todo locator
+    const newTodo = page.getByPlaceholder('What needs to be done?');
+
+    // Create one todo item.
+    await newTodo.fill(TODO_ITEMS[0]);
+    await newTodo.press('Enter');
+
+    // Check that input is empty.
+    await expect(newTodo).toBeEmpty();
+    await checkNumberOfTodosInLocalStorage(page, 1);
+  });
+
+  test('should append new items to the bottom of the list', async ({ page }) => {
+    // Create 3 items.
+    await createDefaultTodos(page);
+
+    // create a todo count locator
+    const todoCount = page.getByTestId('todo-count')
+  
+    // Check test using different methods.
+    await expect(page.getByText('3 items left')).toBeVisible();
+    await expect(todoCount).toHaveText('3 items left');
+    await expect(todoCount).toContainText('3');
+    await expect(todoCount).toHaveText(/3/);
+
+    // Check all items in one call.
+    await expect(page.getByTestId('todo-title')).toHaveText(TODO_ITEMS);
+    await checkNumberOfTodosInLocalStorage(page, 3);
+  });
+});
+
+test.describe('Mark all as completed', () => {
+  test.beforeEach(async ({ page }) => {
+    await createDefaultTodos(page);
+    await checkNumberOfTodosInLocalStorage(page, 3);
+  });
+
+  test.afterEach(async ({ page }) => {
+    await checkNumberOfTodosInLocalStorage(page, 3);
+  });
+
+  test('should allow me to mark all items as completed', async ({ page }) => {
+    // Complete all todos.
+    await page.getByLabel('Mark all as complete').check();
+
+    // Ensure all todos have 'completed' class.
+    await expect(page.getByTestId('todo-item')).toHaveClass(['completed', 'completed', 'completed']);
+    await checkNumberOfCompletedTodosInLocalStorage(page, 3);
+  });
+
+  test('should allow me to clear the complete state of all items', async ({ page }) => {
+    const toggleAll = page.getByLabel('Mark all as complete');
+    // Check and then immediately uncheck.
+    await toggleAll.check();
+    await toggleAll.uncheck();
+
+    // Should be no completed classes.
+    await expect(page.getByTestId('todo-item')).toHaveClass(['', '', '']);
+  });
+
+  test('complete all checkbox should update state when items are completed / cleared', async ({ page }) => {
+    const toggleAll = page.getByLabel('Mark all as complete');
+    await toggleAll.check();
+    await expect(toggleAll).toBeChecked();
+    await checkNumberOfCompletedTodosInLocalStorage(page, 3);
+
+    // Uncheck first todo.
+    const firstTodo = page.getByTestId('todo-item').nth(0);
+    await firstTodo.getByRole('checkbox').uncheck();
+
+    // Reuse toggleAll locator and make sure its not checked.
+    await expect(toggleAll).not.toBeChecked();
+
+    await firstTodo.getByRole('checkbox').check();
+    await checkNumberOfCompletedTodosInLocalStorage(page, 3);
+
+    // Assert the toggle all is checked again.
+    await expect(toggleAll).toBeChecked();
+  });
+});
+
+test.describe('Item', () => {
+
+  test('should allow me to mark items as complete', async ({ page }) => {
+    // create a new todo locator
+    const newTodo = page.getByPlaceholder('What needs to be done?');
+
+    // Create two items.
+    for (const item of TODO_ITEMS.slice(0, 2)) {
+      await newTodo.fill(item);
+      await newTodo.press('Enter');
+    }
+
+    // Check first item.
+    const firstTodo = page.getByTestId('todo-item').nth(0);
+    await firstTodo.getByRole('checkbox').check();
+    await expect(firstTodo).toHaveClass('completed');
+
+    // Check second item.
+    const secondTodo = page.getByTestId('todo-item').nth(1);
+    await expect(secondTodo).not.toHaveClass('completed');
+    await secondTodo.getByRole('checkbox').check();
+
+    // Assert completed class.
+    await expect(firstTodo).toHaveClass('completed');
+    await expect(secondTodo).toHaveClass('completed');
+  });
+
+  test('should allow me to un-mark items as complete', async ({ page }) => {
+    // create a new todo locator
+    const newTodo = page.getByPlaceholder('What needs to be done?');
+
+    // Create two items.
+    for (const item of TODO_ITEMS.slice(0, 2)) {
+      await newTodo.fill(item);
+      await newTodo.press('Enter');
+    }
+
+    const firstTodo = page.getByTestId('todo-item').nth(0);
+    const secondTodo = page.getByTestId('todo-item').nth(1);
+    const firstTodoCheckbox = firstTodo.getByRole('checkbox');
+
+    await firstTodoCheckbox.check();
+    await expect(firstTodo).toHaveClass('completed');
+    await expect(secondTodo).not.toHaveClass('completed');
+    await checkNumberOfCompletedTodosInLocalStorage(page, 1);
+
+    await firstTodoCheckbox.uncheck();
+    await expect(firstTodo).not.toHaveClass('completed');
+    await expect(secondTodo).not.toHaveClass('completed');
+    await checkNumberOfCompletedTodosInLocalStorage(page, 0);
+  });
+
+  test('should allow me to edit an item', async ({ page }) => {
+    await createDefaultTodos(page);
+
+    const todoItems = page.getByTestId('todo-item');
+    const secondTodo = todoItems.nth(1);
+    await secondTodo.dblclick();
+    await expect(secondTodo.getByRole('textbox', { name: 'Edit' })).toHaveValue(TODO_ITEMS[1]);
+    await secondTodo.getByRole('textbox', { name: 'Edit' }).fill('buy some sausages');
+    await secondTodo.getByRole('textbox', { name: 'Edit' }).press('Enter');
+
+    // Explicitly assert the new text value.
+    await expect(todoItems).toHaveText([
+      TODO_ITEMS[0],
+      'buy some sausages',
+      TODO_ITEMS[2]
+    ]);
+    await checkTodosInLocalStorage(page, 'buy some sausages');
+  });
+});
+
+test.describe('Editing', () => {
+  test.beforeEach(async ({ page }) => {
+    await createDefaultTodos(page);
+    await checkNumberOfTodosInLocalStorage(page, 3);
+  });
+
+  test('should hide other controls when editing', async ({ page }) => {
+    const todoItem = page.getByTestId('todo-item').nth(1);
+    await todoItem.dblclick();
+    await expect(todoItem.getByRole('checkbox')).not.toBeVisible();
+    await expect(todoItem.locator('label', {
+      hasText: TODO_ITEMS[1],
+    })).not.toBeVisible();
+    await checkNumberOfTodosInLocalStorage(page, 3);
+  });
+
+  test('should save edits on blur', async ({ page }) => {
+    const todoItems = page.getByTestId('todo-item');
+    await todoItems.nth(1).dblclick();
+    await todoItems.nth(1).getByRole('textbox', { name: 'Edit' }).fill('buy some sausages');
+    await todoItems.nth(1).getByRole('textbox', { name: 'Edit' }).dispatchEvent('blur');
+
+    await expect(todoItems).toHaveText([
+      TODO_ITEMS[0],
+      'buy some sausages',
+      TODO_ITEMS[2],
+    ]);
+    await checkTodosInLocalStorage(page, 'buy some sausages');
+  });
+
+  test('should trim entered text', async ({ page }) => {
+    const todoItems = page.getByTestId('todo-item');
+    await todoItems.nth(1).dblclick();
+    await todoItems.nth(1).getByRole('textbox', { name: 'Edit' }).fill('    buy some sausages    ');
+    await todoItems.nth(1).getByRole('textbox', { name: 'Edit' }).press('Enter');
+
+    await expect(todoItems).toHaveText([
+      TODO_ITEMS[0],
+      'buy some sausages',
+      TODO_ITEMS[2],
+    ]);
+    await checkTodosInLocalStorage(page, 'buy some sausages');
+  });
+
+  test('should remove the item if an empty text string was entered', async ({ page }) => {
+    const todoItems = page.getByTestId('todo-item');
+    await todoItems.nth(1).dblclick();
+    await todoItems.nth(1).getByRole('textbox', { name: 'Edit' }).fill('');
+    await todoItems.nth(1).getByRole('textbox', { name: 'Edit' }).press('Enter');
+
+    await expect(todoItems).toHaveText([
+      TODO_ITEMS[0],
+      TODO_ITEMS[2],
+    ]);
+  });
+
+  test('should cancel edits on escape', async ({ page }) => {
+    const todoItems = page.getByTestId('todo-item');
+    await todoItems.nth(1).dblclick();
+    await todoItems.nth(1).getByRole('textbox', { name: 'Edit' }).fill('buy some sausages');
+    await todoItems.nth(1).getByRole('textbox', { name: 'Edit' }).press('Escape');
+    await expect(todoItems).toHaveText(TODO_ITEMS);
+  });
+});
+
+test.describe('Counter', () => {
+  test('should display the current number of todo items', async ({ page }) => {
+    // create a new todo locator
+    const newTodo = page.getByPlaceholder('What needs to be done?');
+    
+    // create a todo count locator
+    const todoCount = page.getByTestId('todo-count')
+
+    await newTodo.fill(TODO_ITEMS[0]);
+    await newTodo.press('Enter');
+
+    await expect(todoCount).toContainText('1');
+
+    await newTodo.fill(TODO_ITEMS[1]);
+    await newTodo.press('Enter');
+    await expect(todoCount).toContainText('2');
+
+    await checkNumberOfTodosInLocalStorage(page, 2);
+  });
+});
+
+test.describe('Clear completed button', () => {
+  test.beforeEach(async ({ page }) => {
+    await createDefaultTodos(page);
+  });
+
+  test('should display the correct text', async ({ page }) => {
+    await page.locator('.todo-list li .toggle').first().check();
+    await expect(page.getByRole('button', { name: 'Clear completed' })).toBeVisible();
+  });
+
+  test('should remove completed items when clicked', async ({ page }) => {
+    const todoItems = page.getByTestId('todo-item');
+    await todoItems.nth(1).getByRole('checkbox').check();
+    await page.getByRole('button', { name: 'Clear completed' }).click();
+    await expect(todoItems).toHaveCount(2);
+    await expect(todoItems).toHaveText([TODO_ITEMS[0], TODO_ITEMS[2]]);
+  });
+
+  test('should be hidden when there are no items that are completed', async ({ page }) => {
+    await page.locator('.todo-list li .toggle').first().check();
+    await page.getByRole('button', { name: 'Clear completed' }).click();
+    await expect(page.getByRole('button', { name: 'Clear completed' })).toBeHidden();
+  });
+});
+
+test.describe('Persistence', () => {
+  test('should persist its data', async ({ page }) => {
+    // create a new todo locator
+    const newTodo = page.getByPlaceholder('What needs to be done?');
+
+    for (const item of TODO_ITEMS.slice(0, 2)) {
+      await newTodo.fill(item);
+      await newTodo.press('Enter');
+    }
+
+    const todoItems = page.getByTestId('todo-item');
+    const firstTodoCheck = todoItems.nth(0).getByRole('checkbox');
+    await firstTodoCheck.check();
+    await expect(todoItems).toHaveText([TODO_ITEMS[0], TODO_ITEMS[1]]);
+    await expect(firstTodoCheck).toBeChecked();
+    await expect(todoItems).toHaveClass(['completed', '']);
+
+    // Ensure there is 1 completed item.
+    await checkNumberOfCompletedTodosInLocalStorage(page, 1);
+
+    // Now reload.
+    await page.reload();
+    await expect(todoItems).toHaveText([TODO_ITEMS[0], TODO_ITEMS[1]]);
+    await expect(firstTodoCheck).toBeChecked();
+    await expect(todoItems).toHaveClass(['completed', '']);
+  });
+});
+
+test.describe('Routing', () => {
+  test.beforeEach(async ({ page }) => {
+    await createDefaultTodos(page);
+    // make sure the app had a chance to save updated todos in storage
+    // before navigating to a new view, otherwise the items can get lost :(
+    // in some frameworks like Durandal
+    await checkTodosInLocalStorage(page, TODO_ITEMS[0]);
+  });
+
+  test('should allow me to display active items', async ({ page }) => {
+    const todoItem = page.getByTestId('todo-item');
+    await page.getByTestId('todo-item').nth(1).getByRole('checkbox').check();
+
+    await checkNumberOfCompletedTodosInLocalStorage(page, 1);
+    await page.getByRole('link', { name: 'Active' }).click();
+    await expect(todoItem).toHaveCount(2);
+    await expect(todoItem).toHaveText([TODO_ITEMS[0], TODO_ITEMS[2]]);
+  });
+
+  test('should respect the back button', async ({ page }) => {
+    const todoItem = page.getByTestId('todo-item'); 
+    await page.getByTestId('todo-item').nth(1).getByRole('checkbox').check();
+
+    await checkNumberOfCompletedTodosInLocalStorage(page, 1);
+
+    await test.step('Showing all items', async () => {
+      await page.getByRole('link', { name: 'All' }).click();
+      await expect(todoItem).toHaveCount(3);
+    });
+
+    await test.step('Showing active items', async () => {
+      await page.getByRole('link', { name: 'Active' }).click();
+    });
+
+    await test.step('Showing completed items', async () => {
+      await page.getByRole('link', { name: 'Completed' }).click();
+    });
+
+    await expect(todoItem).toHaveCount(1);
+    await page.goBack();
+    await expect(todoItem).toHaveCount(2);
+    await page.goBack();
+    await expect(todoItem).toHaveCount(3);
+  });
+
+  test('should allow me to display completed items', async ({ page }) => {
+    await page.getByTestId('todo-item').nth(1).getByRole('checkbox').check();
+    await checkNumberOfCompletedTodosInLocalStorage(page, 1);
+    await page.getByRole('link', { name: 'Completed' }).click();
+    await expect(page.getByTestId('todo-item')).toHaveCount(1);
+  });
+
+  test('should allow me to display all items', async ({ page }) => {
+    await page.getByTestId('todo-item').nth(1).getByRole('checkbox').check();
+    await checkNumberOfCompletedTodosInLocalStorage(page, 1);
+    await page.getByRole('link', { name: 'Active' }).click();
+    await page.getByRole('link', { name: 'Completed' }).click();
+    await page.getByRole('link', { name: 'All' }).click();
+    await expect(page.getByTestId('todo-item')).toHaveCount(3);
+  });
+
+  test('should highlight the currently applied filter', async ({ page }) => {
+    await expect(page.getByRole('link', { name: 'All' })).toHaveClass('selected');
+    
+    //create locators for active and completed links
+    const activeLink = page.getByRole('link', { name: 'Active' });
+    const completedLink = page.getByRole('link', { name: 'Completed' });
+    await activeLink.click();
+
+    // Page change - active items.
+    await expect(activeLink).toHaveClass('selected');
+    await completedLink.click();
+
+    // Page change - completed items.
+    await expect(completedLink).toHaveClass('selected');
+  });
+});
+
+async function createDefaultTodos(page: Page) {
+  // create a new todo locator
+  const newTodo = page.getByPlaceholder('What needs to be done?');
+
+  for (const item of TODO_ITEMS) {
+    await newTodo.fill(item);
+    await newTodo.press('Enter');
+  }
+}
+
+async function checkNumberOfTodosInLocalStorage(page: Page, expected: number) {
+  return await page.waitForFunction(e => {
+    return JSON.parse(localStorage['react-todos']).length === e;
+  }, expected);
+}
+
+async function checkNumberOfCompletedTodosInLocalStorage(page: Page, expected: number) {
+  return await page.waitForFunction(e => {
+    return JSON.parse(localStorage['react-todos']).filter((todo: any) => todo.completed).length === e;
+  }, expected);
+}
+
+async function checkTodosInLocalStorage(page: Page, title: string) {
+  return await page.waitForFunction(t => {
+    return JSON.parse(localStorage['react-todos']).map((todo: any) => todo.title).includes(t);
+  }, title);
+}