Running tests locally

  1. Build
  2. Set the test as the startup project and press F5 to compile it.
  3. Or in a cmd window, run the test of interest in src\chrome\Debug, e.g. src\chrome\Debug\base_unittests.exe


  1. cd src/
  2. Build
  3. Run the test of interest, e.g. ./out/Debug/base_unittests
Many unit tests create a chromium UI, which means they need the ability to create a visible window. To run these tests remotely in a terminal, or to keep them from opening windows in your current desktop session, you can run tests inside Xvfb. See "Running in headless mode" below.


  1. Build the tests: ninja -C out/{Debug,Release} {test_target}
  2. Run the appropriate test target: ./out/{Debug,Release}/{test_target}

Running a particular subtest

The above test executables are built with gtest, so they accept command line arguments to filter which sub-tests to run.  For instance, base_unittests --gtest_filter=FileUtilTest.*

Making tests show visible output

Tests that create a visible window do not draw anything into the window by default, in order to run the test faster (with exception of tests that verify pixel output). To force tests to draw visible pixels for debugging, you can use the --enable-pixel-output-in-tests command-line flag. This can be used for both unit tests and browser tests.

Layout tests

Blink has a large suite of tests that typically verify a page is laid out properly.  We use them to verify much of the code that runs within a Chromium renderer.
To run these tests, build the blink_tests target and then run blink/tools/layout_tests/ --debug .

More information about running layout tests or fixing layouts tests can be found on the Layout Tests page.

Unit tests and Browser tests

Most components of chrome have a unit test build target, such as content_unittests for content/ or cc_unittests for cc/, etc. There is the fallback unit_tests target for unit tests built on top of the full chrome stack.

Unit tests verify some part of the chromium code base in an isolated test environment, and are usually found in files with a suffix. Browser tests run a full browser, and then execute a test inside the browser instance, and are usually found in files with a suffix. There is more information on browser tests hereTo add a new test, you will generally find a similar test and clone it. If you can, strongly prefer writing a unit test over a browser test as they are generally faster and more reliable.

Get dumps for Chromium crashes on Windows

Before running the tests, make sure to run crash_service.exe. We use this program to intercept crashes in chromium and write a crash dump in the Crash Reports folder under the User Data directory of your chromium profile.

If you also want crash_service.exe to intercept crashes for your normal Google Chrome or Chromium build, add the flag --noerrdialogs.
You can also use the flag --enable-dcheck to get assertion errors in release mode.

Running in headless mode

When ssh-ed in to a machine, you don't have a display connected, which means that you normally can't run tests that try to draw to the screen. However, on Linux, you can run tests in headless mode with xvfb (X Virtual Frame Buffer). There are multiple ways to run tests with xvfb!

Example with unittests and testing/ (note: you will need to install xcompmgr, although this is done as part of

  python testing/ out/Default/components_unittests

Example with browser tests and running Xvfb and setting the DISPLAY env variable. 

  Xvfb :100 -screen 0 1600x1200x24 &

  DISPLAY=localhost:100 out/Default/browser_tests​ --gtest_filter=FooTest.*

Third example, with xvfb-run:

  xvfb-run -s "-screen 0 1024x768x24" ./out/Default/content_unittests