Document how to run (GNU/Linux) GUI tests in Bazel

[radoye]

Description of the bug:

It is unclear how to run GUI tests. For example

bazel test //:my_gui_test --test_arg=--enable_display=true --test_env=DISPLAY --test_output=all

where :my_gui_test contains

  if (glfwInit() != GLFW_TRUE) {
    return absl::AbortedError("GLFW failed to initialize.");
  }

fails with logs (logging code not displayed)

Authorization required, but no authorization protocol specified
[16:19:58.798375] [error] GLFW error 65544: X11: Failed to open display :0

The same code works just fine in a cc_binary when actually executed in the user environment. It seems that, for some reason, test code cannot connect to X11 display.

So, something is different about the test environment in this respect, but I can't seem to find any mention in the docs. Any pointers? Thanks!

Which category does this issue belong to?

No response

What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

Try to open a window from a test, e.g. using GLFW like in the description.

Which operating system are you running Bazel on?

Ubuntu 24.04, Debian testing

What is the output of bazel info release?

release 7.1.2

If bazel info release returns development version or (@non-git), tell us how you built Bazel.

No response

What's the output of git remote get-url origin; git rev-parse HEAD ?

No response

Is this a regression? If yes, please try to identify the Bazel commit where the bug was introduced.

No response

Have you found anything relevant by searching the web?

Tangentially related: https://bazel.build/docs/android-instrumentation-test

Any other information, logs, or outputs that you want to share?

No response

[oquenchil]

Could you please provide a small repro?