MAINT Add pytest.mark.xfail_browsers and use it to reduce boilerplate. Use a decorator to indicate which browsers we want to xfail test. This works for `run_in_pyodide` as well as normal tests.
from functools import cache
from pathlib import Path
from textwrap import dedent
from typing import Any

import pytest
import yaml
from yaml import CLoader as Loader

from pyodide_build.common import UNVENDORED_STDLIB_MODULES


def filter_info(info: dict[str, Any], browser: str) -> dict[str, Any]:
    # keep only flags related to the current browser
    suffix = "-" + browser
    result = {key.removesuffix(suffix): value for key, value in info.items()}
    if "skip" in info and f"skip{suffix}" in info:
        result["skip"] = info["skip"] + info[f"skip{suffix}"]
    return result


def possibly_skip_test(
    request: pytest.FixtureRequest, info: dict[str, Any]
) -> dict[str, Any]:
    if "segfault" in info:
        pytest.skip(f"known segfault: {info['segfault']}")

    if "xfail" in info:
        reason = info["xfail"]
        if request.config.option.run_xfail:
            request.applymarker(
                pytest.mark.xfail(
                    run=False,
                    reason=f"known failure: {reason}",
                )
            )
        else:
            pytest.xfail(f"known failure: {reason}")
    return info


def test_cpython_core(main_test, selenium, request):
    [name, info] = main_test
    info = filter_info(info, selenium.browser)
    possibly_skip_test(request, info)

    ignore_tests = info.get("skip", [])
    if not isinstance(ignore_tests, list):
        raise Exception("Invalid python_tests.yaml entry: 'skip' should be a list")

    selenium.load_package(list(UNVENDORED_STDLIB_MODULES))
    try:
        selenium.run(
            dedent(
                f"""
            import platform
            from test import libregrtest

            platform.platform(aliased=True)
            import _testcapi
            if hasattr(_testcapi, "raise_SIGINT_then_send_None"):
                # This uses raise() which doesn't work.
                del _testcapi.raise_SIGINT_then_send_None

            try:
                libregrtest.main(["{name}"], ignore_tests={ignore_tests}, verbose=True, verbose3=True)
            except SystemExit as e:
                if e.code != 0:
                    raise RuntimeError(f"Failed with code: {{e.code}}")
            """
            )
        )
    except selenium.JavascriptException:
        print(selenium.logs)
        raise


def get_test_info(test: dict[str, Any] | str) -> tuple[str, dict[str, Any]]:
    if isinstance(test, dict):
        (name, info) = next(iter(test.items()))
    else:
        name = test
        info = {}
    return (name, info)


@cache
def get_tests() -> list[tuple[str, dict[str, Any]]]:
    with open(Path(__file__).parent / "python_tests.yaml") as file:
        data = yaml.load(file, Loader)

    return [get_test_info(test) for test in data]


def pytest_generate_tests(metafunc):
    if "main_test" in metafunc.fixturenames:
        tests = get_tests()
        metafunc.parametrize("main_test", tests, ids=[t[0] for t in tests])

from functools import cache
from pathlib import Path
from textwrap import dedent
from typing import Any

import pytest
import yaml
from yaml import CLoader as Loader

from pyodide_build.common import UNVENDORED_STDLIB_MODULES


def filter_info(info: dict[str, Any], browser: str) -> dict[str, Any]:
    # keep only flags related to the current browser
    suffix = "-" + browser
    result = {key.removesuffix(suffix): value for key, value in info.items()}
    if "skip" in info and f"skip{suffix}" in info:
        result["skip"] = info["skip"] + info[f"skip{suffix}"]
    return result


def possibly_skip_test(
    request: pytest.FixtureRequest, info: dict[str, Any]
) -> dict[str, Any]:
    if "segfault" in info:
        pytest.skip(f"known segfault: {info['segfault']}")

    if "xfail" in info:
        reason = info["xfail"]
        if request.config.option.run_xfail:
            request.applymarker(
                pytest.mark.xfail(
                    run=False,
                    reason=f"known failure: {reason}",
                )
            )
        else:
            pytest.xfail(f"known failure: {reason}")
    return info


def test_cpython_core(main_test, selenium, request):
    [name, info] = main_test
    info = filter_info(info, selenium.browser)
    possibly_skip_test(request, info)

    ignore_tests = info.get("skip", [])
    if not isinstance(ignore_tests, list):
        raise Exception("Invalid python_tests.yaml entry: 'skip' should be a list")

    selenium.load_package(list(UNVENDORED_STDLIB_MODULES))
    try:
        selenium.run(
            dedent(
                f"""
            import platform
            from test import libregrtest

            platform.platform(aliased=True)
            import _testcapi
            if hasattr(_testcapi, "raise_SIGINT_then_send_None"):
                # This uses raise() which doesn't work.
                del _testcapi.raise_SIGINT_then_send_None

            try:
                libregrtest.main(["{name}"], ignore_tests={ignore_tests}, verbose=True, verbose3=True)
            except SystemExit as e:
                if e.code != 0:
                    raise RuntimeError(f"Failed with code: {{e.code}}")
            """
            )
        )
    except selenium.JavascriptException:
        print(selenium.logs)
        raise


def get_test_info(test: dict[str, Any] | str) -> tuple[str, dict[str, Any]]:
    if isinstance(test, dict):
        (name, info) = next(iter(test.items()))
    else:
        name = test
        info = {}
    return (name, info)


@cache
def get_tests() -> list[tuple[str, dict[str, Any]]]:
    with open(Path(__file__).parent / "python_tests.yaml") as file:
        data = yaml.load(file, Loader)

    return [get_test_info(test) for test in data]


def pytest_generate_tests(metafunc):
    if "main_test" in metafunc.fixturenames:
        tests = get_tests()
        metafunc.parametrize("main_test", tests, ids=[t[0] for t in tests])
