I'm running this on an Apple Silicon mac, this is what I get:

trees/mozilla-unified::phab-D148524_1$ mach wpt --product chrome testing/web-platform/tests/webaudio/the-audio-api/the-audiocontext-interface/audiocontext-suspend-resume-close.html
 0:00.00 INFO Skipping manifest download because existing file is recent
Error running mach:

    ['wpt', '--product', 'chrome', 'testing/web-platform/tests/webaudio/the-audio-api/the-audiocontext-interface/audiocontext-suspend-resume-close.html']

The error occurred in code that was called by the mach command. This is either
a bug in the called code itself or in the way that mach is calling it.
You can invoke |./mach busted| to check if this issue is already on file. If it
isn't, please use |./mach busted file wpt| to report it. If |./mach busted| is
misbehaving, you can also inspect the dependencies of bug 1543241.

If filing a bug, please include the full output of mach, including this error
message.

The details of the failure are as follows:

FileNotFoundError: [Errno 2] No such file or directory: '/Users/padenot/src/trees/mozilla-unified/obj-aarch64-apple-darwin21.4.0/_virtualenvs/common/bin/python'

  File "/Users/padenot/src/trees/mozilla-unified/testing/web-platform/mach_commands.py", line 531, in run_wpt
    return run_web_platform_tests(command_context, **params)
  File "/Users/padenot/src/trees/mozilla-unified/testing/web-platform/mach_commands.py", line 520, in run_web_platform_tests
    return wpt_runner.run(logger, **params)
  File "/Users/padenot/src/trees/mozilla-unified/testing/web-platform/mach_commands_base.py", line 57, in run
    kwargs = self.setup.kwargs_wptrun(kwargs)
  File "/Users/padenot/src/trees/mozilla-unified/testing/web-platform/mach_commands.py", line 188, in kwargs_wptrun
    self.virtualenv_manager.install_pip_requirements(
  File "/Users/padenot/src/trees/mozilla-unified/python/mach/mach/site.py", line 638, in install_pip_requirements
    install_result = self._virtualenv.pip_install(
  File "/Users/padenot/src/trees/mozilla-unified/python/mach/mach/site.py", line 847, in pip_install
    return subprocess.run(
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/subprocess.py", line 505, in run
    with Popen(*popenargs, **kwargs) as process:
  File "/Users/padenot/src/trees/mozilla-unified/third_party/python/sentry_sdk/sentry_sdk/integrations/stdlib.py", line 190, in sentry_patched_popen_init
    rv = old_popen_init(self, *a, **kw)  # type: ignore
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/subprocess.py", line 951, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/subprocess.py", line 1821, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)

Sentry event ID: 329fb1a6a2a94e88b52332a51c799721

Running a similar command on linux also gives me similar errors

❯ ./mach wpt --product chrome --binary /usr/bin/chromium testing/web-platform/tests/largest-contentful-paint
 0:00.00 INFO Skipping manifest download because existing file is recent
Error running mach:

    ['wpt', '--product', 'chrome', '--binary', '/usr/bin/chromium', 'testing/web-platform/tests/largest-contentful-paint']

The error occurred in code that was called by the mach command. This is either
a bug in the called code itself or in the way that mach is calling it.
You can invoke |./mach busted| to check if this issue is already on file. If it
isn't, please use |./mach busted file wpt| to report it. If |./mach busted| is
misbehaving, you can also inspect the dependencies of bug 1543241.

If filing a bug, please include the full output of mach, including this error
message.

The details of the failure are as follows:

FileNotFoundError: [Errno 2] No such file or directory: '/home/sefeng/.local/workspace/mozilla/mozilla-unified3/.build-obj/release/_virtualenvs/common/bin/python'

  File "/home/sefeng/.local/workspace/mozilla/mozilla-unified3/testing/web-platform/mach_commands.py", line 531, in run_wpt
    return run_web_platform_tests(command_context, **params)
  File "/home/sefeng/.local/workspace/mozilla/mozilla-unified3/testing/web-platform/mach_commands.py", line 520, in run_web_platform_tests
    return wpt_runner.run(logger, **params)
  File "/home/sefeng/.local/workspace/mozilla/mozilla-unified3/testing/web-platform/mach_commands_base.py", line 57, in run
    kwargs = self.setup.kwargs_wptrun(kwargs)
  File "/home/sefeng/.local/workspace/mozilla/mozilla-unified3/testing/web-platform/mach_commands.py", line 188, in kwargs_wptrun
    self.virtualenv_manager.install_pip_requirements(
  File "/home/sefeng/.local/workspace/mozilla/mozilla-unified3/python/mach/mach/site.py", line 638, in install_pip_requirements
    install_result = self._virtualenv.pip_install(
  File "/home/sefeng/.local/workspace/mozilla/mozilla-unified3/python/mach/mach/site.py", line 846, in pip_install
    return subprocess.run(
  File "/usr/lib/python3.10/subprocess.py", line 501, in run
    with Popen(*popenargs, **kwargs) as process:
  File "/home/sefeng/.local/workspace/mozilla/mozilla-unified3/third_party/python/sentry_sdk/sentry_sdk/integrations/stdlib.py", line 190, in sentry_patched_popen_init
    rv = old_popen_init(self, *a, **kw)  # type: ignore
  File "/usr/lib/python3.10/subprocess.py", line 969, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.10/subprocess.py", line 1845, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)

Sentry event ID: a6bf5c80c8f343e48474725a9e221916

We need to access the virtualenv to install dependencies when running
with other browsers, but _spawn doesn't correctly pass this down into
the created MozbuildObject.

For now just work around the problem by setting the property on the
created object.

The severity field is not set for this bug.
:jgraham, could you have a look please?

For more information, please visit auto_nag documentation.

https://hg.mozilla.org/mozilla-central/rev/e7c1d97b7f83

I am still getting the same error with today's m-c (Confirmed the patch is in there).

I'm getting a different error (which is apparently because I don't have /usr/bin/chromium, which I'm not sure why I need to run Chrome, but must be an upstream change). However the virtualenv stuff works. Can you verify that wptsetup._virtualenv_name is "wpt" in the line right after the patch but that the virtualenv_manager.virtualenv_root is set to something ending /common at https://searchfox.org/mozilla-central/source/testing/web-platform/mach_commands.py#192-194 ?

For me I got this

VirtualEnv Name: common
VirtualEnv Manager /home/sefeng/.local/workspace/mozilla/mozilla-unified3/.build-obj/release/_virtualenvs/common