Test Runners

Introduction

While Playwright for .NET isn't tied to a particular test runner or testing framework, in our experience the easiest way of getting started is by using the base classes we provide for MSTest and NUnit. These classes support running tests on multiple browser engines, adjusting launch/context options and getting a Page/BrowserContext instance per test out of the box.

Playwright and Browser instances will be reused between tests for better performance. We recommend running each test case in a new BrowserContext, this way browser state will be isolated between the tests.

MSTest

Playwright provides base classes to write tests with MSTest via the Microsoft.Playwright.MSTest package.

Check out the installation guide to get started.

Running MSTest tests in Parallel

By default MSTest will run all classes in parallel, while running tests inside each class sequentially (ExecutionScope.ClassLevel). It will create as many processes as there are cores on the host system. You can adjust this behavior by using the following CLI parameter or using a .runsettings file, see below. Running tests in parallel at the method level (ExecutionScope.MethodLevel) is not supported.

dotnet test --settings:.runsettings -- MSTest.Parallelize.Workers=4

Customizing BrowserContext options

To customize context options, you can override the ContextOptions method of your test class derived from Microsoft.Playwright.MSTest.PageTest or Microsoft.Playwright.MSTest.ContextTest. See the following example:

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 TestWithCustomContextOptions()
    {
        // The following Page (and BrowserContext) instance has the custom colorScheme, viewport and baseURL set:
        await Page.GotoAsync("/login");
    }

    public override BrowserNewContextOptions ContextOptions()
    {
        return new BrowserNewContextOptions()
        {
            ColorScheme = ColorScheme.Light,
            ViewportSize = new()
            {
                Width = 1920,
                Height = 1080
            },
            BaseURL = "https://github.com",
        };
    }
}

Customizing Browser/launch options

Browser/launch options can be overridden either using a run settings file or by setting the run settings options directly via the CLI. See the following example:

<?xml version="1.0" encoding="utf-8"?>
<RunSettings>
  <Playwright>
    <BrowserName>chromium</BrowserName>
    <LaunchOptions>
      <Headless>false</Headless>
      <Channel>msedge</Channel>
    </LaunchOptions>
  </Playwright>
</RunSettings>

dotnet test -- Playwright.BrowserName=chromium Playwright.LaunchOptions.Headless=false Playwright.LaunchOptions.Channel=msedge

Using Verbose API Logs

When you have enabled the verbose API log, via the DEBUG environment variable, you will see the messages in the standard error stream. In MSTest, within Visual Studio, that will be the Tests pane of the Output window. It will also be displayed in the Test Log for each test.

Using the .runsettings file

When running tests from Visual Studio, you can take advantage of the .runsettings file. The following shows a reference of the supported values.

For example, to specify the number of workers, you can use MSTest.Parallelize.Workers. You can also enable DEBUG logs using RunConfiguration.EnvironmentVariables.

<RunSettings>
  <!-- MSTest adapter -->  
  <MSTest>
    <Parallelize>
      <Workers>4</Workers>
      <Scope>ClassLevel</Scope>
    </Parallelize>
  </MSTest>
  <!-- General run configuration -->
  <RunConfiguration>
    <EnvironmentVariables>
      <!-- For debugging selectors, it's recommend to set the following environment variable -->
      <DEBUG>pw:api</DEBUG>
    </EnvironmentVariables>
  </RunConfiguration>
  <!-- Playwright -->  
  <Playwright>
    <BrowserName>chromium</BrowserName>
    <ExpectTimeout>5000</ExpectTimeout>
    <LaunchOptions>
      <Headless>false</Headless>
      <Channel>msedge</Channel>
    </LaunchOptions>
  </Playwright>
</RunSettings>

Base MSTest classes for Playwright

There are a few base classes available to you in Microsoft.Playwright.MSTest namespace:

Test	Description
PageTest	Each test gets a fresh copy of a web Page created in its own unique BrowserContext. Extending this class is the simplest way of writing a fully-functional Playwright test. Note: You can override the ContextOptions method in each test file to control context options, the ones typically passed into the Browser.NewContextAsync() method. That way you can specify all kinds of emulation options for your test file individually.
ContextTest	Each test will get a fresh copy of a BrowserContext. You can create as many pages in this context as you'd like. Using this test is the easiest way to test multi-page scenarios where you need more than one tab. Note: You can override the ContextOptions method in each test file to control context options, the ones typically passed into the Browser.NewContextAsync() method. That way you can specify all kinds of emulation options for your test file individually.
BrowserTest	Each test will get a browser and can create as many contexts as it likes. Each test is responsible for cleaning up all the contexts it created.
PlaywrightTest	This gives each test a Playwright object so that the test could start and stop as many browsers as it likes.

NUnit

Playwright provides base classes to write tests with NUnit via the Microsoft.Playwright.NUnit package.

Check out the installation guide to get started.

Running NUnit tests in Parallel

By default NUnit will run all test files in parallel, while running tests inside each file sequentially (ParallelScope.Self). It will create as many processes as there are cores on the host system. You can adjust this behavior using the NUnit.NumberOfTestWorkers parameter. Only ParallelScope.Self is supported.

For CPU-bound tests, we recommend using as many workers as there are cores on your system, divided by 2. For IO-bound tests you can use as many workers as you have cores.

dotnet test -- NUnit.NumberOfTestWorkers=5

Customizing BrowserContext options

To customize context options, you can override the ContextOptions method of your test class derived from Microsoft.Playwright.MSTest.PageTest or Microsoft.Playwright.MSTest.ContextTest. See the following example:

using Microsoft.Playwright.NUnit;

namespace PlaywrightTests;

[Parallelizable(ParallelScope.Self)]
[TestFixture]
public class MyTest : PageTest
{
    [Test]
    public async Task TestWithCustomContextOptions()
    {
        // The following Page (and BrowserContext) instance has the custom colorScheme, viewport and baseURL set:
        await Page.GotoAsync("/login");
    }

    public override BrowserNewContextOptions ContextOptions()
    {
        return new BrowserNewContextOptions()
        {
            ColorScheme = ColorScheme.Light,
            ViewportSize = new()
            {
                Width = 1920,
                Height = 1080
            },
            BaseURL = "https://github.com",
        };
    }
}

Customizing Browser/launch options

Browser/launch options can be overridden either using a run settings file or by setting the run settings options directly via the CLI. See the following example:

<?xml version="1.0" encoding="utf-8"?>
<RunSettings>
  <Playwright>
    <BrowserName>chromium</BrowserName>
    <LaunchOptions>
      <Headless>false</Headless>
      <Channel>msedge</Channel>
    </LaunchOptions>
  </Playwright>
</RunSettings>

dotnet test -- Playwright.BrowserName=chromium Playwright.LaunchOptions.Headless=false Playwright.LaunchOptions.Channel=msedge

Using Verbose API Logs

When you have enabled the verbose API log, via the DEBUG environment variable, you will see the messages in the standard error stream. In NUnit, within Visual Studio, that will be the Tests pane of the Output window. It will also be displayed in the Test Log for each test.

Using the .runsettings file

When running tests from Visual Studio, you can take advantage of the .runsettings file. The following shows a reference of the supported values.

For example, to specify the amount of workers you can use NUnit.NumberOfTestWorkers or to enable DEBUG logs RunConfiguration.EnvironmentVariables.

<?xml version="1.0" encoding="utf-8"?>
<RunSettings>
  <!-- NUnit adapter -->  
  <NUnit>
    <NumberOfTestWorkers>24</NumberOfTestWorkers>
  </NUnit>
  <!-- General run configuration -->
  <RunConfiguration>
    <EnvironmentVariables>
      <!-- For debugging selectors, it's recommend to set the following environment variable -->
      <DEBUG>pw:api</DEBUG>
    </EnvironmentVariables>
  </RunConfiguration>
  <!-- Playwright -->  
  <Playwright>
    <BrowserName>chromium</BrowserName>
    <ExpectTimeout>5000</ExpectTimeout>
    <LaunchOptions>
      <Headless>false</Headless>
      <Channel>msedge</Channel>
    </LaunchOptions>
  </Playwright>
</RunSettings>

Base NUnit classes for Playwright

There are a few base classes available to you in Microsoft.Playwright.NUnit namespace:

Test	Description
PageTest	Each test gets a fresh copy of a web Page created in its own unique BrowserContext. Extending this class is the simplest way of writing a fully-functional Playwright test. Note: You can override the ContextOptions method in each test file to control context options, the ones typically passed into the Browser.NewContextAsync() method. That way you can specify all kinds of emulation options for your test file individually.
ContextTest	Each test will get a fresh copy of a BrowserContext. You can create as many pages in this context as you'd like. Using this test is the easiest way to test multi-page scenarios where you need more than one tab. Note: You can override the ContextOptions method in each test file to control context options, the ones typically passed into the Browser.NewContextAsync() method. That way you can specify all kinds of emulation options for your test file individually.
BrowserTest	Each test will get a browser and can create as many contexts as it likes. Each test is responsible for cleaning up all the contexts it created.
PlaywrightTest	This gives each test a Playwright object so that the test could start and stop as many browsers as it likes.

xUnit support

While using xUnit is also supported, we do not support running parallel tests. This is a well known problem/design limitation outlined by the maintainers across several issues.