writing-tests-csharp.md

id	title
writing-tests	Writing tests

Introduction

Playwright tests are simple, they

• perform actions, and
• assert the state against expectations.

There is no need to wait for anything prior to performing an action: Playwright automatically waits for the wide range of actionability checks to pass prior to performing each action.

There is also no need to deal with the race conditions when performing the checks - Playwright assertions are designed in a way that they describe the expectations that need to be eventually met.

That's it! These design choices allow Playwright users to forget about flaky timeouts and racy checks in their tests altogether.

You will learn

• How to write the first test
• How to perform actions
• How to use assertions
• How tests run in isolation
• How to use test hooks

First test

Take a look at the following example to see how to write a test.

<Tabs groupId="test-runners" defaultValue="mstest" values={[ {label: 'MSTest', value: 'mstest'}, {label: 'NUnit', value: 'nunit'}, ] }>

using System.Text.RegularExpressions;
using System.Threading.Tasks;
using Microsoft.Playwright;
using Microsoft.Playwright.NUnit;
using NUnit.Framework;

namespace PlaywrightTests;

[Parallelizable(ParallelScope.Self)]
[TestFixture]
public class ExampleTest : PageTest
{
    [Test]
    public async Task HasTitle()
    {
        await Page.GotoAsync("https://playwright.dev");

        // Expect a title "to contain" a substring.
        await Expect(Page).ToHaveTitleAsync(new Regex("Playwright"));
    }

    [Test]
    public async Task GetStartedLink()
    {
        await Page.GotoAsync("https://playwright.dev");

        // Click the get started link.
        await Page.GetByRole(AriaRole.Link, new() { Name = "Get started" }).ClickAsync();

        // Expects page to have a heading with the name of Installation.
        await Expect(Page.GetByRole(AriaRole.Heading, new() { Name = "Installation" })).ToBeVisibleAsync();
    } 
}

using System.Text.RegularExpressions;
using System.Threading.Tasks;
using Microsoft.Playwright;
using Microsoft.Playwright.MSTest;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace PlaywrightTests;

[TestClass]
public class ExampleTest : PageTest
{
    [TestMethod]
    public async Task HasTitle()
    {
        await Page.GotoAsync("https://playwright.dev");

        // Expect a title "to contain" a substring.
        await Expect(Page).ToHaveTitleAsync(new Regex("Playwright"));
    }

    [TestMethod]
    public async Task GetStartedLink()
    {
        await Page.GotoAsync("https://playwright.dev");

        // Click the get started link.
        await Page.GetByRole(AriaRole.Link, new() { Name = "Get started" }).ClickAsync();

        // Expects page to have a heading with the name of Installation.
        await Expect(Page.GetByRole(AriaRole.Heading, new() { Name = "Installation" })).ToBeVisibleAsync();
    } 
}

Actions

Navigation

Most of the tests will start by navigating the page to a URL. After that, the test will be able to interact with the page elements.

await Page.GotoAsync("https://playwright.dev");

Playwright will wait for the page to reach the load state prior to moving forward. Learn more about the [method: Page.goto] options.

Interactions

Performing actions starts with locating the elements. Playwright uses Locators API for that. Locators represent a way to find element(s) on the page at any moment, learn more about the different types of locators available. Playwright will wait for the element to be actionable prior to performing the action, so there is no need to wait for it to become available.

// Create a locator.
var getStarted = Page.GetByRole(AriaRole.Link, new() { Name = "Get started" });

// Click it.
await getStarted.ClickAsync();

In most cases, it'll be written in one line:

await Page.GetByRole(AriaRole.Link, new() { Name = "Get started" }).ClickAsync();

Basic actions

This is the list of the most popular Playwright actions. Note that there are many more, so make sure to check the Locator API section to learn more about them.

Action	Description
[method: Locator.check]	Check the input checkbox
[method: Locator.click]	Click the element
[method: Locator.uncheck]	Uncheck the input checkbox
[method: Locator.hover]	Hover mouse over the element
[method: Locator.fill]	Fill the form field, input text
[method: Locator.focus]	Focus the element
[method: Locator.press]	Press single key
[method: Locator.setInputFiles]	Pick files to upload
[method: Locator.selectOption]	Select option in the drop down

Assertions

Playwright provides an async function called Expect to assert and wait until the expected condition is met.

await Expect(Page).ToHaveTitleAsync(new Regex("Playwright"));

Here is the list of the most popular async assertions. Note that there are many more to get familiar with:

Assertion	Description
[method: LocatorAssertions.toBeChecked]	Checkbox is checked
[method: LocatorAssertions.toBeEnabled]	Control is enabled
[method: LocatorAssertions.toBeVisible]	Element is visible
[method: LocatorAssertions.toContainText]	Element contains text
[method: LocatorAssertions.toHaveAttribute]	Element has attribute
[method: LocatorAssertions.toHaveCount]	List of elements has given length
[method: LocatorAssertions.toHaveText]	Element matches text
[method: LocatorAssertions.toHaveValue]	Input element has value
[method: PageAssertions.toHaveTitle]	Page has title
[method: PageAssertions.toHaveURL]	Page has URL

Test Isolation

The Playwright NUnit and MSTest test framework base classes will isolate each test from each other by providing a separate Page instance. Pages are isolated between tests due to the Browser Context, which is equivalent to a brand new browser profile, where every test gets a fresh environment, even when multiple tests run in a single Browser.

<Tabs groupId="test-runners" defaultValue="mstest" values={[ {label: 'MSTest', value: 'mstest'}, {label: 'NUnit', value: 'nunit'}, ] }>

using System.Threading.Tasks;
using Microsoft.Playwright.NUnit;
using NUnit.Framework;

namespace PlaywrightTests;

[Parallelizable(ParallelScope.Self)]
[TestFixture]
public class ExampleTest : PageTest
{
    [Test]
    public async Task BasicTest()
    {
        await Page.GotoAsync("https://playwright.dev");
    }
}

using System.Threading.Tasks;
using Microsoft.Playwright.MSTest;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace PlaywrightTests;

[TestClass]
public class ExampleTest : PageTest
{
    [TestMethod]
    public async Task BasicTest()
    {
        await Page.GotoAsync("https://playwright.dev");
    }
}

Using Test Hooks

You can use SetUp/TearDown in NUnit or TestInitialize/TestCleanup in MSTest to prepare and clean up your test environment:

<Tabs groupId="test-runners" defaultValue="mstest" values={[ {label: 'MSTest', value: 'mstest'}, {label: 'NUnit', value: 'nunit'}, ] }>

using System.Threading.Tasks;
using Microsoft.Playwright.NUnit;
using NUnit.Framework;

namespace PlaywrightTests;

[Parallelizable(ParallelScope.Self)]
[TestFixture]
public class ExampleTest : PageTest
{
    [Test]
    public async Task MainNavigation()
    {
        // Assertions use the expect API.
        await Expect(Page).ToHaveURLAsync("https://playwright.dev/");
    }

    [SetUp]
    public async Task SetUp()
    {
        await Page.GotoAsync("https://playwright.dev");
    }
}

using System.Threading.Tasks;
using Microsoft.Playwright.MSTest;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace PlaywrightTests;

[TestClass]
public class ExampleTest : PageTest
{
    [TestMethod]
    public async Task MainNavigation()
    {
        // Assertions use the expect API.
        await Expect(Page).ToHaveURLAsync("https://playwright.dev/");
    }

    [TestInitialize]
    public async Task TestInitialize()
    {
        await Page.GotoAsync("https://playwright.dev");
    }
}

What's Next

• Run single test, multiple tests, headed mode
• Generate tests with Codegen
• See a trace of your tests
• Run tests on CI
• Learn more about the MSTest and NUnit base classes