Fri. Dec 9th, 2022

With a few lines of code, you can hook up Playwright to your favorite Java test runner.

Playwright and Browser instances can 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.

JUnit

In JUnit you can initialize Playwright and Browser in @BeforeAll method and destroy them in @AfterAll. In the example below all three test methods use the same Browser. Each test uses its own BrowserContext and Page

package org.example;

import com.microsoft.playwright.Browser;
import com.microsoft.playwright.BrowserContext;
import com.microsoft.playwright.Page;
import com.microsoft.playwright.Playwright;
import org.junit.jupiter.api.*;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertTrue;

public class TestExample {
  // Shared between all tests in this class.
  static Playwright playwright;
  static Browser browser;

  // New instance for each test method.
  BrowserContext context;
  Page page;

  @BeforeAll
  static void launchBrowser() {
    playwright = Playwright.create();
    browser = playwright.chromium().launch();
  }

  @AfterAll
  static void closeBrowser() {
    playwright.close();
  }

  @BeforeEach
  void createContextAndPage() {
    context = browser.newContext();
    page = context.newPage();
  }

  @AfterEach
  void closeContext() {
    context.close();
  }

  @Test
  void shouldClickButton() {
    page.navigate("data:text/html,<script>var result;</script><button onclick='result=\"Clicked\"'>Go</button>");
    page.locator("button").click();
    assertEquals("Clicked", page.evaluate("result"));
  }

  @Test
  void shouldCheckTheBox() {
    page.setContent("<input id='checkbox' type='checkbox'></input>");
    page.locator("input").check();
    assertTrue((Boolean) page.evaluate("() => window['checkbox'].checked"));
  }

  @Test
  void shouldSearchWiki() {
    page.navigate("https://www.wikipedia.org/");
    page.locator("input[name=\"search\"]").click();
    page.locator("input[name=\"search\"]").fill("playwright");
    page.locator("input[name=\"search\"]").press("Enter");
    assertEquals("https://en.wikipedia.org/wiki/Playwright", page.url());
  }
}

Running Tests in Parallel

By default JUnit will run all tests sequentially on a single thread. Since JUnit 5.3 you can change this behavior to run tests in parallel to speed up execution. Since it is not safe to use same Playwright objects from multiple threads without extra synchronization we recommend you create Playwright instance per thread and use it on that thread exclusively. Here is an example how to run multiple test classes in parallel.

Use @TestInstance(TestInstance.Lifecycle.PER_CLASS) annotation to make JUnit create one instance of a class for all test methods within that class (by default each JUnit will create a new instance of the class for each test method). Store Playwright and Browser objects in instance fields. They will be shared between tests. Each instance of the class will use its own copy of Playwright.

// Subclasses will inherit PER_CLASS behavior.
@TestInstance(TestInstance.Lifecycle.PER_CLASS)
class TestFixtures {
  // Shared between all tests in the class.
  Playwright playwright;
  Browser browser;

  @BeforeAll
  void launchBrowser() {
    playwright = Playwright.create();
    browser = playwright.chromium().launch();
  }

  @AfterAll
  void closeBrowser() {
    playwright.close();
  }

  // New instance for each test method.
  BrowserContext context;
  Page page;

  @BeforeEach
  void createContextAndPage() {
    context = browser.newContext();
    page = context.newPage();
  }

  @AfterEach
  void closeContext() {
    context.close();
  }
}

class Test1 extends TestFixtures {
  @Test
  void shouldClickButton() {
    page.navigate("data:text/html,<script>var result;</script><button onclick='result=\"Clicked\"'>Go</button>");
    page.locator("button").click();
    assertEquals("Clicked", page.evaluate("result"));
  }

  @Test
  void shouldCheckTheBox() {
    page.setContent("<input id='checkbox' type='checkbox'></input>");
    page.locator("input").check();
    assertTrue((Boolean) page.evaluate("() => window['checkbox'].checked"));
  }

  @Test
  void shouldSearchWiki() {
    page.navigate("https://www.wikipedia.org/");
    page.locator("input[name=\"search\"]").click();
    page.locator("input[name=\"search\"]").fill("playwright");
    page.locator("input[name=\"search\"]").press("Enter");
    assertEquals("https://en.wikipedia.org/wiki/Playwright", page.url());
  }
}

class Test2 extends TestFixtures {
  @Test
  void shouldReturnInnerHTML() {
    page.setContent("<div>hello</div>");
    assertEquals("hello", page.innerHTML("css=div"));
  }

  @Test
  void shouldClickButton() {
    Page popup = page.waitForPopup(() -> {
      page.evaluate("window.open('about:blank');");
    });
    assertEquals("about:blank", popup.url());
  }
}

Configure JUnit to run tests in each class sequentially and run multiple classes on parallel threads (with max number of thread equal to 1/2 of the number of CPU cores):

junit.jupiter.execution.parallel.enabled = true
junit.jupiter.execution.parallel.mode.default = same_thread
junit.jupiter.execution.parallel.mode.classes.default = concurrent
junit.jupiter.execution.parallel.config.strategy=dynamic
junit.jupiter.execution.parallel.config.dynamic.factor=0.5

By Rajashekar

I’m (Rajashekar) a core Android developer with complimenting skills as a web developer from India. I cherish taking up complex problems and turning them into beautiful interfaces. My love for decrypting the logic and structure of coding keeps me pushing towards writing elegant and proficient code, whether it is Android, PHP, Flutter or any other platforms. You would find me involved in cuisines, reading, travelling during my leisure hours.

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