Re-Creating Page Objects in Playwright?

Question

In Playwright (Like many other automation frameworks) you can create page objects. Using an example from Playwrights documentation: https://playwright.dev/docs/test-fixtures#without-fixtures

You have a .spec file that looks like this (The actual page object class itself can be seen above, not posting it just because it's long):

const { test } = require('@playwright/test');
const { TodoPage } = require('./todo-page');

test.describe('todo tests', () => {
  let todoPage;

  test.beforeEach(async ({ page }) => {
    todoPage = new TodoPage(page);
    await todoPage.goto();
    await todoPage.addToDo('item1');
    await todoPage.addToDo('item2');
  });

  test.afterEach(async () => {
    await todoPage.removeAll();
  });

  test('should add an item', async () => {
    await todoPage.addToDo('my item');
    // ...
  });

  test('should remove an item', async () => {
    await todoPage.remove('item1');
    // ...
  });
});

However I wonder in such a case is there really a need to re-create the page object before each test? Wouldn't creating the page object once be good enough? (Since we would have access to all the methods/etc... and those shouldn't be changing between tests?

Is there any reason to re-create a page object for each test?

Vishal Aggarwal · Accepted Answer · 2023-09-07 18:07:20Z

3

Use beforeAll to instantiate page object so that all tests in a file can share the page object as todoPage is suite level variable declared outside any test.

test.beforeAll(async ({ page }) => {
    todoPage = new TodoPage(page);
  });

The Playwright Docs suggest to use as beforeEach to promote test isolation so that tests can be run in parallel as they should be absolutely independent.

edited Sep 7, 2023 at 18:07

answered Jun 13, 2023 at 16:31

Vishal Aggarwal

1

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6 Comments

msmith1114 Over a year ago

Thats sort of what I assumed you should do, so I was curious why the official docs had them as beforeEach

Vishal Aggarwal Over a year ago

The reason playwright docs suggest that to promote test isolation so that they can also be run in parallel.

msmith1114 Over a year ago

Thats a good point. But even with beforeAll wouldn't it still not matter? Since we aren't really doing anything besides using methods/locators (and therefore aren't really "sharing" anything between the tests)

Vishal Aggarwal Over a year ago

I faced a problem where I shared an "orderID" on class level and incidentally changed that value in one of the tests and many other tests started failing for no reason. Eventually it turned out that unexpected value was causing the problem.

msmith1114 Over a year ago

Good point. I guess that could happen if you are passing values to any of the methods (for filling out forms/etc...). I guess the object is destroyed at the end of each block anyways so execution time doesn't really matter anyways.

|

Kiran Parajuli · Accepted Answer · 2023-06-14 05:55:03Z

0

We can create static PageObjects like:

class StaticPageObject() {
  // no constructor

  static clickSomeBtn(page) {
   // now page should be feed to the PO methods
   page.locator("some-static-selector").click()
  }
}

With this we can use PageObject methods like:

StaticPageObject.clickSomeBtn(page) // no initialization required

If page is made global (which is not a good approach), then,

class StaticPageObject() {
  // no constructor

  static clickSomeBtn() {
   // now page should be feed to the PO methods
   global.page.locator("some-static-selector").click()
  }
}

answered Jun 14, 2023 at 5:55

Kiran Parajuli

1,0668 silver badges17 bronze badges

3 Comments

Vishal Aggarwal Over a year ago

Static methods act as global variables which in general a bad approach as they are against the core philosophy of OOP as they violate base principles like data hiding, encapsulation.

Vishal Aggarwal Over a year ago

Anything can access and modify them without explicit object initiation.

Kiran Parajuli Over a year ago

It is true that explicit object initiation is not required for Static variables or method invocation, but they do not act as global variables or methods, but they are scoped to the class.

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