diff --git a/.circleci/config.yml b/.circleci/config.yml
index d673ebb75..17fbcb1b6 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -215,7 +215,7 @@ jobs:
               --verbose \
               -k 'not (chrome or firefox or node)' \
               --cov=pyodide_build --cov=pyodide \
-              src pyodide-build packages/micropip/
+              src pyodide-build packages/micropip/ pyodide-test-runner
 
       - store_test_results:
           path: test-results
@@ -411,7 +411,7 @@ workflows:
 
       - test-main:
           name: test-core-chrome
-          test-params: -k "chrome and not webworker" src packages/micropip  packages/fpcast-test packages/sharedlib-test-py/ packages/cpp-exceptions-test/
+          test-params: -k "chrome and not webworker" src packages/micropip  packages/fpcast-test packages/sharedlib-test-py/ packages/cpp-exceptions-test/ pyodide-test-runner
           requires:
             - build-core
           filters:
@@ -420,7 +420,7 @@ workflows:
 
       - test-main:
           name: test-core-firefox
-          test-params: -k "firefox and not webworker" src packages/micropip packages/fpcast-test packages/sharedlib-test-py/ packages/cpp-exceptions-test/
+          test-params: -k "firefox and not webworker" src packages/micropip packages/fpcast-test packages/sharedlib-test-py/ packages/cpp-exceptions-test/ pyodide-test-runner
           requires:
             - build-core
           filters:
@@ -429,7 +429,7 @@ workflows:
 
       - test-main:
           name: test-core-node
-          test-params: -k node src packages/micropip packages/fpcast-test packages/sharedlib-test-py/ packages/cpp-exceptions-test/
+          test-params: -k node src packages/micropip packages/fpcast-test packages/sharedlib-test-py/ packages/cpp-exceptions-test/ pyodide-test-runner
           requires:
             - build-core
           filters:
diff --git a/benchmark/benchmark.py b/benchmark/benchmark.py
index a9c10a590..9de6aa305 100644
--- a/benchmark/benchmark.py
+++ b/benchmark/benchmark.py
@@ -7,8 +7,13 @@ from pathlib import Path
 from time import time
 
 sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+sys.path.append(str(Path(__file__).resolve().parents[1] / "pyodide-test-runner"))
 
-import conftest  # noqa: E402
+from pyodide_test_runner import (  # noqa: E402
+    ChromeWrapper,
+    FirefoxWrapper,
+    spawn_web_server,
+)
 
 SKIP = {"fft", "hyantes"}
 
@@ -150,6 +155,11 @@ def parse_args(benchmarks):
         type=int,
         help="Browser timeout(sec) for each benchmark (default: %(default)s)",
     )
+    parser.add_argument(
+        "--dist-dir",
+        default=str(Path(__file__).parents[1] / "dist"),
+        help="Pyodide dist directory (default: %(default)s)",
+    )
 
     return parser.parse_args()
 
@@ -171,11 +181,11 @@ def main():
     results = {}
     selenium_backends = {}
     browser_cls = [
-        ("firefox", conftest.FirefoxWrapper),
-        ("chrome", conftest.ChromeWrapper),
+        ("firefox", FirefoxWrapper),
+        ("chrome", ChromeWrapper),
     ]
 
-    with conftest.spawn_web_server() as (hostname, port, log_path):
+    with spawn_web_server(args.dist_dir) as (hostname, port, log_path):
 
         # selenium initialization time
         result = {"native": float("NaN")}
diff --git a/conftest.py b/conftest.py
index 684cc17ee..643429ea1 100644
--- a/conftest.py
+++ b/conftest.py
@@ -1,31 +1,34 @@
 """
 Various common utilities for testing.
 """
-import contextlib
-import functools
-import json
-import multiprocessing
-import os
 import pathlib
-import queue
-import re
-import shutil
 import sys
-import tempfile
-import textwrap
-import time
 
-import pexpect
 import pytest
 
 ROOT_PATH = pathlib.Path(__file__).parents[0].resolve()
-TEST_PATH = ROOT_PATH / "src" / "tests"
 DIST_PATH = ROOT_PATH / "dist"
 
+sys.path.append(str(ROOT_PATH / "pyodide-test-runner"))
 sys.path.append(str(ROOT_PATH / "pyodide-build"))
 sys.path.append(str(ROOT_PATH / "src" / "py"))
 
-from pyodide_build.testing import parse_driver_timeout, set_webdriver_script_timeout
+from pyodide_test_runner.fixture import (  # noqa: F401
+    script_type,
+    selenium,
+    selenium_common,
+    selenium_context_manager,
+    selenium_esm,
+    selenium_module_scope,
+    selenium_standalone,
+    selenium_standalone_noload,
+    selenium_standalone_noload_common,
+    selenium_webworker_standalone,
+    web_server_main,
+    web_server_secondary,
+)
+from pyodide_test_runner.utils import maybe_skip_test
+from pyodide_test_runner.utils import package_is_built as _package_is_built
 
 
 def pytest_addoption(parser):
@@ -50,6 +53,8 @@ def pytest_configure(config):
     it to reduce the verbosity of the test names in the table.  This leaves
     enough room to see the information about the test failure in the summary.
     """
+    global CONFIG
+
     old_cwd_relative_nodeid = config.cwd_relative_nodeid
 
     def cwd_relative_nodeid(*args):
@@ -61,6 +66,8 @@ def pytest_configure(config):
 
     config.cwd_relative_nodeid = cwd_relative_nodeid
 
+    pytest.pyodide_dist_dir = config.getoption("--dist-dir")
+
 
 def pytest_collection_modifyitems(config, items):
     """Called after collect is completed.
@@ -70,400 +77,7 @@ def pytest_collection_modifyitems(config, items):
     items : list of collected items
     """
     for item in items:
-        _maybe_skip_test(item, delayed=True)
-
-
-@functools.cache
-def built_packages() -> list[str]:
-    """Returns the list of built package names from packages.json"""
-    packages_json_path = DIST_PATH / "packages.json"
-    if not packages_json_path.exists():
-        return []
-    return list(json.loads(packages_json_path.read_text())["packages"].keys())
-
-
-def _package_is_built(package_name: str) -> bool:
-    return package_name.lower() in built_packages()
-
-
-class JavascriptException(Exception):
-    def __init__(self, msg, stack):
-        self.msg = msg
-        self.stack = stack
-        # In chrome the stack contains the message
-        if self.stack and self.stack.startswith(self.msg):
-            self.msg = ""
-
-    def __str__(self):
-        return "\n\n".join(x for x in [self.msg, self.stack] if x)
-
-
-class SeleniumWrapper:
-    JavascriptException = JavascriptException
-
-    def __init__(
-        self,
-        server_port,
-        server_hostname="127.0.0.1",
-        server_log=None,
-        load_pyodide=True,
-        script_timeout=20,
-        script_type="classic",
-    ):
-        self.server_port = server_port
-        self.server_hostname = server_hostname
-        self.base_url = f"http://{self.server_hostname}:{self.server_port}"
-        self.server_log = server_log
-        self.script_type = script_type
-        self.driver = self.get_driver()  # type: ignore[attr-defined]
-        self.set_script_timeout(script_timeout)
-        self.script_timeout = script_timeout
-        self.prepare_driver()
-        self.javascript_setup()
-        if load_pyodide:
-            self.load_pyodide()
-            self.initialize_global_hiwire_objects()
-            self.save_state()
-            self.restore_state()
-
-    SETUP_CODE = pathlib.Path(ROOT_PATH / "tools/testsetup.js").read_text()
-
-    def prepare_driver(self):
-        if self.script_type == "classic":
-            self.driver.get(f"{self.base_url}/test.html")
-        elif self.script_type == "module":
-            self.driver.get(f"{self.base_url}/module_test.html")
-        else:
-            raise Exception("Unknown script type to load!")
-
-    def set_script_timeout(self, timeout):
-        self.driver.set_script_timeout(timeout)
-
-    def quit(self):
-        self.driver.quit()
-
-    def refresh(self):
-        self.driver.refresh()
-        self.javascript_setup()
-
-    def javascript_setup(self):
-        self.run_js(
-            SeleniumWrapper.SETUP_CODE,
-            pyodide_checks=False,
-        )
-
-    def load_pyodide(self):
-        self.run_js(
-            """
-            let pyodide = await loadPyodide({ fullStdLib: false, jsglobals : self });
-            self.pyodide = pyodide;
-            globalThis.pyodide = pyodide;
-            pyodide._api.inTestHoist = true; // improve some error messages for tests
-            """
-        )
-
-    def initialize_global_hiwire_objects(self):
-        """
-        There are a bunch of global objects that occasionally enter the hiwire cache
-        but never leave. The refcount checks get angry about them if they aren't preloaded.
-        We need to go through and touch them all once to keep everything okay.
-        """
-        self.run_js(
-            """
-            pyodide.globals.get;
-            pyodide.pyodide_py.eval_code;
-            pyodide.pyodide_py.eval_code_async;
-            pyodide.pyodide_py.register_js_module;
-            pyodide.pyodide_py.unregister_js_module;
-            pyodide.pyodide_py.find_imports;
-            pyodide._api.importlib.invalidate_caches;
-            pyodide._api.package_loader.unpack_buffer;
-            pyodide._api.package_loader.get_dynlibs;
-            pyodide.runPython("");
-            """
-        )
-
-    @property
-    def pyodide_loaded(self):
-        return self.run_js("return !!(self.pyodide && self.pyodide.runPython);")
-
-    @property
-    def logs(self):
-        logs = self.run_js("return self.logs;", pyodide_checks=False)
-        if logs is not None:
-            return "\n".join(str(x) for x in logs)
-        return ""
-
-    def clean_logs(self):
-        self.run_js("self.logs = []", pyodide_checks=False)
-
-    def run(self, code):
-        return self.run_js(
-            f"""
-            let result = pyodide.runPython({code!r});
-            if(result && result.toJs){{
-                let converted_result = result.toJs();
-                if(pyodide.isPyProxy(converted_result)){{
-                    converted_result = undefined;
-                }}
-                result.destroy();
-                return converted_result;
-            }}
-            return result;
-            """
-        )
-
-    def run_async(self, code):
-        return self.run_js(
-            f"""
-            await pyodide.loadPackagesFromImports({code!r})
-            let result = await pyodide.runPythonAsync({code!r});
-            if(result && result.toJs){{
-                let converted_result = result.toJs();
-                if(pyodide.isPyProxy(converted_result)){{
-                    converted_result = undefined;
-                }}
-                result.destroy();
-                return converted_result;
-            }}
-            return result;
-            """
-        )
-
-    def run_js(self, code, pyodide_checks=True):
-        """Run JavaScript code and check for pyodide errors"""
-        if isinstance(code, str) and code.startswith("\n"):
-            # we have a multiline string, fix indentation
-            code = textwrap.dedent(code)
-
-        if pyodide_checks:
-            check_code = """
-                    if(globalThis.pyodide && pyodide._module && pyodide._module._PyErr_Occurred()){
-                        try {
-                            pyodide._module._pythonexc2js();
-                        } catch(e){
-                            console.error(`Python exited with error flag set! Error was:\n${e.message}`);
-                            // Don't put original error message in new one: we want
-                            // "pytest.raises(xxx, match=msg)" to fail
-                            throw new Error(`Python exited with error flag set!`);
-                        }
-                    }
-           """
-        else:
-            check_code = ""
-        return self.run_js_inner(code, check_code)
-
-    def run_js_inner(self, code, check_code):
-        wrapper = """
-            let cb = arguments[arguments.length - 1];
-            let run = async () => { %s }
-            (async () => {
-                try {
-                    let result = await run();
-                    %s
-                    cb([0, result]);
-                } catch (e) {
-                    cb([1, e.toString(), e.stack, e.message]);
-                }
-            })()
-        """
-        retval = self.driver.execute_async_script(wrapper % (code, check_code))
-        if retval[0] == 0:
-            return retval[1]
-        else:
-            print("JavascriptException message: ", retval[3])
-            raise JavascriptException(retval[1], retval[2])
-
-    def get_num_hiwire_keys(self):
-        return self.run_js("return pyodide._module.hiwire.num_keys();")
-
-    @property
-    def force_test_fail(self) -> bool:
-        return self.run_js("return !!pyodide._api.fail_test;")
-
-    def clear_force_test_fail(self):
-        self.run_js("pyodide._api.fail_test = false;")
-
-    def save_state(self):
-        self.run_js("self.__savedState = pyodide._api.saveState();")
-
-    def restore_state(self):
-        self.run_js(
-            """
-            if(self.__savedState){
-                pyodide._api.restoreState(self.__savedState)
-            }
-            """
-        )
-
-    def get_num_proxies(self):
-        return self.run_js("return pyodide._module.pyproxy_alloc_map.size")
-
-    def enable_pyproxy_tracing(self):
-        self.run_js("pyodide._module.enable_pyproxy_allocation_tracing()")
-
-    def disable_pyproxy_tracing(self):
-        self.run_js("pyodide._module.disable_pyproxy_allocation_tracing()")
-
-    def run_webworker(self, code):
-        if isinstance(code, str) and code.startswith("\n"):
-            # we have a multiline string, fix indentation
-            code = textwrap.dedent(code)
-
-        worker_file = (
-            "webworker_dev.js"
-            if self.script_type == "classic"
-            else "module_webworker_dev.js"
-        )
-
-        return self.run_js(
-            """
-            let worker = new Worker('{}', {{ type: '{}' }});
-            let res = new Promise((res, rej) => {{
-                worker.onerror = e => rej(e);
-                worker.onmessage = e => {{
-                    if (e.data.results) {{
-                       res(e.data.results);
-                    }} else {{
-                       rej(e.data.error);
-                    }}
-                }};
-                worker.postMessage({{ python: {!r} }});
-            }});
-            return await res
-            """.format(
-                f"http://{self.server_hostname}:{self.server_port}/{worker_file}",
-                self.script_type,
-                code,
-            ),
-            pyodide_checks=False,
-        )
-
-    def load_package(self, packages):
-        self.run_js(f"await pyodide.loadPackage({packages!r})")
-
-    @property
-    def urls(self):
-        for handle in self.driver.window_handles:
-            self.driver.switch_to.window(handle)
-            yield self.driver.current_url
-
-
-class FirefoxWrapper(SeleniumWrapper):
-
-    browser = "firefox"
-
-    def get_driver(self):
-        from selenium.webdriver import Firefox
-        from selenium.webdriver.firefox.options import Options
-
-        options = Options()
-        options.add_argument("--headless")
-
-        return Firefox(executable_path="geckodriver", options=options)
-
-
-class ChromeWrapper(SeleniumWrapper):
-
-    browser = "chrome"
-
-    def get_driver(self):
-        from selenium.webdriver import Chrome
-        from selenium.webdriver.chrome.options import Options
-
-        options = Options()
-        options.add_argument("--headless")
-        options.add_argument("--no-sandbox")
-        options.add_argument("--js-flags=--expose-gc")
-        return Chrome(options=options)
-
-    def collect_garbage(self):
-        self.driver.execute_cdp_cmd("HeapProfiler.collectGarbage", {})
-
-
-class NodeWrapper(SeleniumWrapper):
-    browser = "node"
-
-    def init_node(self):
-        self.p = pexpect.spawn("/bin/bash", timeout=60)
-        self.p.setecho(False)
-        self.p.delaybeforesend = None
-        # disable canonical input processing mode to allow sending longer lines
-        # See: https://pexpect.readthedocs.io/en/stable/api/pexpect.html#pexpect.spawn.send
-        self.p.sendline("stty -icanon")
-        self.p.sendline(
-            f"node --expose-gc --experimental-wasm-bigint ./src/test-js/node_test_driver.js {self.base_url}",
-        )
-
-        try:
-            self.p.expect_exact("READY!!")
-        except pexpect.exceptions.EOF:
-            raise JavascriptException("", self.p.before.decode())
-
-    def get_driver(self):
-        self._logs = []
-        self.init_node()
-
-        class NodeDriver:
-            def __getattr__(self, x):
-                raise NotImplementedError()
-
-        return NodeDriver()
-
-    def prepare_driver(self):
-        pass
-
-    def set_script_timeout(self, timeout):
-        self._timeout = timeout
-
-    def quit(self):
-        self.p.sendeof()
-
-    def refresh(self):
-        self.quit()
-        self.init_node()
-        self.javascript_setup()
-
-    def collect_garbage(self):
-        self.run_js("gc()")
-
-    @property
-    def logs(self):
-        return "\n".join(self._logs)
-
-    def clean_logs(self):
-        self._logs = []
-
-    def run_js_inner(self, code, check_code):
-        check_code = ""
-        wrapped = """
-            let result = await (async () => {{ {} }})();
-            {}
-            return result;
-        """.format(
-            code,
-            check_code,
-        )
-        from uuid import uuid4
-
-        cmd_id = str(uuid4())
-        try:
-            self.p.sendline(cmd_id)
-            self.p.sendline(wrapped)
-            self.p.sendline(cmd_id)
-            self.p.expect_exact(f"{cmd_id}:UUID\r\n", timeout=self._timeout)
-            self.p.expect_exact(f"{cmd_id}:UUID\r\n")
-            if self.p.before:
-                self._logs.append(self.p.before.decode()[:-2].replace("\r", ""))
-            self.p.expect("[01]\r\n")
-            success = int(self.p.match[0].decode()[0]) == 0
-            self.p.expect_exact(f"\r\n{cmd_id}:UUID\r\n")
-        except pexpect.exceptions.EOF:
-            raise JavascriptException("", self.p.before.decode())
-        if success:
-            return json.loads(self.p.before.decode().replace("undefined", "null"))
-        else:
-            raise JavascriptException("", self.p.before.decode())
+        maybe_skip_test(item, config.getoption("--dist-dir"), delayed=True)
 
 
 @pytest.hookimpl(hookwrapper=True)
@@ -479,342 +93,57 @@ def pytest_runtest_call(item):
     Pytest issue #5044:
     https://github.com/pytest-dev/pytest/issues/5044
     """
-    selenium = None
+    browser = None
     for fixture in item._fixtureinfo.argnames:
         if fixture.startswith("selenium"):
-            selenium = item.funcargs[fixture]
+            browser = item.funcargs[fixture]
             break
-    if selenium and selenium.pyodide_loaded:
+    if browser and browser.pyodide_loaded:
         trace_pyproxies = pytest.mark.skip_pyproxy_check.mark not in item.own_markers
         trace_hiwire_refs = (
             trace_pyproxies
             and pytest.mark.skip_refcount_check.mark not in item.own_markers
         )
         yield from extra_checks_test_wrapper(
-            selenium, trace_hiwire_refs, trace_pyproxies
+            browser, trace_hiwire_refs, trace_pyproxies
         )
     else:
         yield
 
 
-def extra_checks_test_wrapper(selenium, trace_hiwire_refs, trace_pyproxies):
+def extra_checks_test_wrapper(browser, trace_hiwire_refs, trace_pyproxies):
     """Extra conditions for test to pass:
     1. No explicit request for test to fail
     2. No leaked JsRefs
     3. No leaked PyProxys
     """
-    selenium.clear_force_test_fail()
-    init_num_keys = selenium.get_num_hiwire_keys()
+    browser.clear_force_test_fail()
+    init_num_keys = browser.get_num_hiwire_keys()
     if trace_pyproxies:
-        selenium.enable_pyproxy_tracing()
-        init_num_proxies = selenium.get_num_proxies()
+        browser.enable_pyproxy_tracing()
+        init_num_proxies = browser.get_num_proxies()
     a = yield
     try:
         # If these guys cause a crash because the test really screwed things up,
         # we override the error message with the better message returned by
         # a.result() in the finally block.
-        selenium.disable_pyproxy_tracing()
-        selenium.restore_state()
+        browser.disable_pyproxy_tracing()
+        browser.restore_state()
     finally:
         # if there was an error in the body of the test, flush it out by calling
         # get_result (we don't want to override the error message by raising a
         # different error here.)
         a.get_result()
-    if selenium.force_test_fail:
+    if browser.force_test_fail:
         raise Exception("Test failure explicitly requested but no error was raised.")
     if trace_pyproxies and trace_hiwire_refs:
-        delta_proxies = selenium.get_num_proxies() - init_num_proxies
-        delta_keys = selenium.get_num_hiwire_keys() - init_num_keys
+        delta_proxies = browser.get_num_proxies() - init_num_proxies
+        delta_keys = browser.get_num_hiwire_keys() - init_num_keys
         assert (delta_proxies, delta_keys) == (0, 0) or delta_keys < 0
     if trace_hiwire_refs:
-        delta_keys = selenium.get_num_hiwire_keys() - init_num_keys
+        delta_keys = browser.get_num_hiwire_keys() - init_num_keys
         assert delta_keys <= 0
 
 
-def _maybe_skip_test(item, delayed=False):
-    """If necessary skip test at the fixture level, to avoid
-
-    loading the selenium_standalone fixture which takes a long time.
-    """
-    skip_msg = None
-    # Testing a package. Skip the test if the package is not built.
-    match = re.match(
-        r".*/packages/(?P<name>[\w\-]+)/test_[\w\-]+\.py", str(item.parent.fspath)
-    )
-    if match:
-        package_name = match.group("name")
-        if not _package_is_built(package_name):
-            skip_msg = f"package '{package_name}' is not built."
-
-    # Common package import test. Skip it if the package is not built.
-    if (
-        skip_msg is None
-        and str(item.fspath).endswith("test_packages_common.py")
-        and item.name.startswith("test_import")
-    ):
-        match = re.match(
-            r"test_import\[(firefox|chrome|node)-(?P<name>[\w-]+)\]", item.name
-        )
-        if match:
-            package_name = match.group("name")
-            if not _package_is_built(package_name):
-                # If the test is going to be skipped remove the
-                # selenium_standalone as it takes a long time to initialize
-                skip_msg = f"package '{package_name}' is not built."
-        else:
-            raise AssertionError(
-                f"Couldn't parse package name from {item.name}. This should not happen!"
-            )
-
-    # TODO: also use this hook to skip doctests we cannot run (or run them
-    # inside the selenium wrapper)
-
-    if skip_msg is not None:
-        if delayed:
-            item.add_marker(pytest.mark.skip(reason=skip_msg))
-        else:
-            pytest.skip(skip_msg)
-
-
-@contextlib.contextmanager
-def selenium_common(request, web_server_main, load_pyodide=True, script_type="classic"):
-    """Returns an initialized selenium object.
-
-    If `_should_skip_test` indicate that the test will be skipped,
-    return None, as initializing Pyodide for selenium is expensive
-    """
-
-    server_hostname, server_port, server_log = web_server_main
-    cls: type[SeleniumWrapper]
-    if request.param == "firefox":
-        cls = FirefoxWrapper
-    elif request.param == "chrome":
-        cls = ChromeWrapper
-    elif request.param == "node":
-        cls = NodeWrapper
-    else:
-        raise AssertionError(f"Unknown browser: {request.param}")
-    selenium = cls(
-        server_port=server_port,
-        server_hostname=server_hostname,
-        server_log=server_log,
-        load_pyodide=load_pyodide,
-        script_type=script_type,
-    )
-    try:
-        yield selenium
-    finally:
-        selenium.quit()
-
-
-@pytest.fixture(params=["firefox", "chrome", "node"], scope="function")
-def selenium_standalone(request, web_server_main):
-    # Avoid loading the fixture if the test is going to be skipped
-    _maybe_skip_test(request.node)
-
-    with selenium_common(request, web_server_main) as selenium:
-        with set_webdriver_script_timeout(
-            selenium, script_timeout=parse_driver_timeout(request)
-        ):
-            try:
-                yield selenium
-            finally:
-                print(selenium.logs)
-
-
-@pytest.fixture(params=["firefox", "chrome", "node"], scope="module")
-def selenium_esm(request, web_server_main):
-    # Avoid loading the fixture if the test is going to be skipped
-    _maybe_skip_test(request.node)
-
-    with selenium_common(
-        request, web_server_main, load_pyodide=True, script_type="module"
-    ) as selenium:
-        with set_webdriver_script_timeout(
-            selenium, script_timeout=parse_driver_timeout(request)
-        ):
-            try:
-                yield selenium
-            finally:
-                print(selenium.logs)
-
-
-@contextlib.contextmanager
-def selenium_standalone_noload_common(request, web_server_main, script_type="classic"):
-    # Avoid loading the fixture if the test is going to be skipped
-    _maybe_skip_test(request.node)
-
-    with selenium_common(
-        request, web_server_main, load_pyodide=False, script_type=script_type
-    ) as selenium:
-        with set_webdriver_script_timeout(
-            selenium, script_timeout=parse_driver_timeout(request)
-        ):
-            try:
-                yield selenium
-            finally:
-                print(selenium.logs)
-
-
-@pytest.fixture(params=["firefox", "chrome"], scope="function")
-def selenium_webworker_standalone(request, web_server_main, script_type):
-    # Avoid loading the fixture if the test is going to be skipped
-    if request.param == "firefox" and script_type == "module":
-        pytest.skip("firefox does not support module type web worker")
-    _maybe_skip_test(request.node)
-    with selenium_standalone_noload_common(
-        request, web_server_main, script_type=script_type
-    ) as selenium:
-        yield selenium
-
-
-@pytest.fixture(params=["classic", "module"], scope="module")
-def script_type(request):
-    return request.param
-
-
-@pytest.fixture(params=["firefox", "chrome", "node"], scope="function")
-def selenium_standalone_noload(request, web_server_main):
-    """Only difference between this and selenium_webworker_standalone is that
-    this also tests on node."""
-    # Avoid loading the fixture if the test is going to be skipped
-    _maybe_skip_test(request.node)
-    with selenium_standalone_noload_common(request, web_server_main) as selenium:
-        yield selenium
-
-
-# selenium instance cached at the module level
-@pytest.fixture(params=["firefox", "chrome", "node"], scope="module")
-def selenium_module_scope(request, web_server_main):
-    with selenium_common(request, web_server_main) as selenium:
-        yield selenium
-
-
-# Hypothesis is unhappy with function scope fixtures. Instead, use the
-# module scope fixture `selenium_module_scope` and use:
-# `with selenium_context_manager(selenium_module_scope) as selenium`
-@contextlib.contextmanager
-def selenium_context_manager(selenium_module_scope):
-    try:
-        selenium_module_scope.clean_logs()
-        yield selenium_module_scope
-    finally:
-        print(selenium_module_scope.logs)
-
-
-@pytest.fixture
-def selenium(request, selenium_module_scope):
-    with selenium_context_manager(selenium_module_scope) as selenium:
-        with set_webdriver_script_timeout(
-            selenium, script_timeout=parse_driver_timeout(request)
-        ):
-            yield selenium
-
-
-@pytest.fixture(scope="session")
-def web_server_main(request):
-    """Web server that serves files in the dist/ directory"""
-    with spawn_web_server(request.config.option.dist_dir) as output:
-        yield output
-
-
-@pytest.fixture(scope="session")
-def web_server_secondary(request):
-    """Secondary web server that serves files dist/ directory"""
-    with spawn_web_server(request.config.option.dist_dir) as output:
-        yield output
-
-
-@pytest.fixture(scope="session")
-def web_server_tst_data(request):
-    """Web server that serves files in the src/tests/data/ directory"""
-    with spawn_web_server(TEST_PATH / "data") as output:
-        yield output
-
-
-@contextlib.contextmanager
-def spawn_web_server(dist_dir=None):
-
-    if dist_dir is None:
-        dist_dir = DIST_PATH
-
-    tmp_dir = tempfile.mkdtemp()
-    log_path = pathlib.Path(tmp_dir) / "http-server.log"
-    q: multiprocessing.Queue[str] = multiprocessing.Queue()
-    p = multiprocessing.Process(target=run_web_server, args=(q, log_path, dist_dir))
-
-    try:
-        p.start()
-        port = q.get()
-        hostname = "127.0.0.1"
-
-        print(
-            f"Spawning webserver at http://{hostname}:{port} "
-            f"(see logs in {log_path})"
-        )
-        yield hostname, port, log_path
-    finally:
-        q.put("TERMINATE")
-        p.join()
-        shutil.rmtree(tmp_dir)
-
-
-def run_web_server(q, log_filepath, dist_dir):
-    """Start the HTTP web server
-
-    Parameters
-    ----------
-    q : Queue
-      communication queue
-    log_path : pathlib.Path
-      path to the file where to store the logs
-    """
-    import http.server
-    import socketserver
-
-    os.chdir(dist_dir)
-
-    log_fh = log_filepath.open("w", buffering=1)
-    sys.stdout = log_fh
-    sys.stderr = log_fh
-
-    class Handler(http.server.SimpleHTTPRequestHandler):
-        def log_message(self, format_, *args):
-            print(
-                "[%s] source: %s:%s - %s"
-                % (self.log_date_time_string(), *self.client_address, format_ % args)
-            )
-
-        def end_headers(self):
-            # Enable Cross-Origin Resource Sharing (CORS)
-            self.send_header("Access-Control-Allow-Origin", "*")
-            super().end_headers()
-
-    with socketserver.TCPServer(("", 0), Handler) as httpd:
-        host, port = httpd.server_address
-        print(f"Starting webserver at http://{host}:{port}")
-        httpd.server_name = "test-server"  # type: ignore[attr-defined]
-        httpd.server_port = port  # type: ignore[attr-defined]
-        q.put(port)
-
-        def service_actions():
-            try:
-                if q.get(False) == "TERMINATE":
-                    print("Stopping server...")
-                    sys.exit(0)
-            except queue.Empty:
-                pass
-
-        httpd.service_actions = service_actions  # type: ignore[assignment]
-        httpd.serve_forever()
-
-
-if (
-    __name__ == "__main__"
-    and multiprocessing.current_process().name == "MainProcess"
-    and not hasattr(sys, "_pytest_session")
-):
-    with spawn_web_server():
-        # run forever
-        while True:
-            time.sleep(1)
+def package_is_built(package_name):
+    return _package_is_built(package_name, pytest.pyodide_dist_dir)
diff --git a/docs/development/testing.md b/docs/development/testing.md
index ea9f03aee..41de0592c 100644
--- a/docs/development/testing.md
+++ b/docs/development/testing.md
@@ -86,10 +86,10 @@ make lint
 
 Many tests simply involve running a chunk of code in Pyodide and ensuring it
 doesn't error. In this case, one can use the `run_in_pyodide` decorate from
-`pyodide_build.testing`, e.g.
+`pyodide_test_runner.decorator`, e.g.
 
 ```python
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 @run_in_pyodide
 def test_add():
@@ -108,7 +108,7 @@ The `packages` option lists packages to load before running the test. For
 example,
 
 ```python
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 @run_in_pyodide(standalone = True, packages = ["regex"])
 def test_regex():
diff --git a/docs/project/changelog.md b/docs/project/changelog.md
index 92b6add4f..9995d423b 100644
--- a/docs/project/changelog.md
+++ b/docs/project/changelog.md
@@ -54,6 +54,10 @@ substitutions:
   translated to negative Python ints.
   {pr}`2484`
 
+- {{ BREAKING }} `pyodide_build.testing` is removed. `run_in_pyodide` decorator can now be accessed
+  through `pyodide_test_runner`.
+  {pr}`2418`
+
 - {{ Enhancement }} Added the `js_id` attribute to `JsProxy` to allow using
   JavaScript object identity as a dictionary key.
   {pr}`2515`
diff --git a/packages/Jinja2/test_jinja2.py b/packages/Jinja2/test_jinja2.py
index fe512f787..360243107 100644
--- a/packages/Jinja2/test_jinja2.py
+++ b/packages/Jinja2/test_jinja2.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["Jinja2"])
diff --git a/packages/Pillow/test_pillow.py b/packages/Pillow/test_pillow.py
index c15b89f85..4ef2d3aac 100644
--- a/packages/Pillow/test_pillow.py
+++ b/packages/Pillow/test_pillow.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(
diff --git a/packages/bitarray/test_bitarray.py b/packages/bitarray/test_bitarray.py
index 5d94b368e..34cc49d3a 100644
--- a/packages/bitarray/test_bitarray.py
+++ b/packages/bitarray/test_bitarray.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["bitarray-tests"])
diff --git a/packages/boost-histogram/test_boost_histogram.py b/packages/boost-histogram/test_boost_histogram.py
index 2605194d5..dd31d347d 100644
--- a/packages/boost-histogram/test_boost_histogram.py
+++ b/packages/boost-histogram/test_boost_histogram.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["boost-histogram"])
diff --git a/packages/cffi/test_cffi.py b/packages/cffi/test_cffi.py
index c3fca3571..ed4d6222f 100644
--- a/packages/cffi/test_cffi.py
+++ b/packages/cffi/test_cffi.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["cffi"])
diff --git a/packages/cffi_example/test_cffi_example.py b/packages/cffi_example/test_cffi_example.py
index 987ff1be5..cb542d290 100644
--- a/packages/cffi_example/test_cffi_example.py
+++ b/packages/cffi_example/test_cffi_example.py
@@ -1,6 +1,5 @@
 import pytest
-
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 CHROME_FAIL_v90_MSG = (
     "Doesn't work in chrome v89 or v90, I think because of "
diff --git a/packages/cloudpickle/test_cloudpickle.py b/packages/cloudpickle/test_cloudpickle.py
index e60a16050..dbc2de1f3 100644
--- a/packages/cloudpickle/test_cloudpickle.py
+++ b/packages/cloudpickle/test_cloudpickle.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["cloudpickle"])
diff --git a/packages/cryptography/test_cryptography.py b/packages/cryptography/test_cryptography.py
index 5415bcb12..195b20e70 100644
--- a/packages/cryptography/test_cryptography.py
+++ b/packages/cryptography/test_cryptography.py
@@ -1,8 +1,7 @@
 from hypothesis import HealthCheck, given, settings
 from hypothesis.strategies import binary, integers
-
-from conftest import selenium_context_manager
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
+from pyodide_test_runner.fixture import selenium_context_manager
 
 
 @run_in_pyodide(packages=["cryptography"])
diff --git a/packages/fpcast-test/test_fpcast_test.py b/packages/fpcast-test/test_fpcast_test.py
index 39e6e6f3a..4207fe33a 100644
--- a/packages/fpcast-test/test_fpcast_test.py
+++ b/packages/fpcast-test/test_fpcast_test.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["fpcast-test"])
diff --git a/packages/imageio/test_imageio.py b/packages/imageio/test_imageio.py
index 1cde0bcf6..e4f600a9f 100644
--- a/packages/imageio/test_imageio.py
+++ b/packages/imageio/test_imageio.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(standalone=True, packages=["numpy", "imageio"])
diff --git a/packages/jedi/test_jedi.py b/packages/jedi/test_jedi.py
index 7c311f119..191dab607 100644
--- a/packages/jedi/test_jedi.py
+++ b/packages/jedi/test_jedi.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(standalone=True, packages=["jedi"])
diff --git a/packages/lazy-object-proxy/test_lazy_object_proxy.py b/packages/lazy-object-proxy/test_lazy_object_proxy.py
index 61a1ee92b..92e144dec 100644
--- a/packages/lazy-object-proxy/test_lazy_object_proxy.py
+++ b/packages/lazy-object-proxy/test_lazy_object_proxy.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["lazy-object-proxy"])
diff --git a/src/tests/data/snowballstemmer-2.0.0-py2.py3-none-any.whl b/packages/micropip/test/snowballstemmer-2.0.0-py2.py3-none-any.whl
similarity index 100%
rename from src/tests/data/snowballstemmer-2.0.0-py2.py3-none-any.whl
rename to packages/micropip/test/snowballstemmer-2.0.0-py2.py3-none-any.whl
diff --git a/packages/micropip/test_micropip.py b/packages/micropip/test_micropip.py
index c585d8740..c1e78649b 100644
--- a/packages/micropip/test_micropip.py
+++ b/packages/micropip/test_micropip.py
@@ -6,8 +6,7 @@ from pathlib import Path
 from typing import Any
 
 import pytest
-
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide, spawn_web_server
 
 sys.path.append(str(Path(__file__).resolve().parent / "src"))
 
@@ -162,17 +161,15 @@ def test_parse_wheel_url():
 @pytest.mark.parametrize("base_url", ["'{base_url}'", "'.'"])
 def test_install_custom_url(selenium_standalone_micropip, base_url):
     selenium = selenium_standalone_micropip
-    base_url = base_url.format(base_url=selenium.base_url)
 
-    root = Path(__file__).resolve().parents[2]
-    src = root / "src" / "tests" / "data"
-    target = root / "dist" / "test_data"
-    target.symlink_to(src, True)
-    path = "/test_data/snowballstemmer-2.0.0-py2.py3-none-any.whl"
-    try:
+    with spawn_web_server(Path(__file__).parent / "test") as server:
+        server_hostname, server_port, _ = server
+        base_url = f"http://{server_hostname}:{server_port}/"
+        url = base_url + "snowballstemmer-2.0.0-py2.py3-none-any.whl"
+
         selenium.run_js(
             f"""
-            let url = {base_url} + '{path}';
+            let url = '{url}';
             let resp = await fetch(url);
             await pyodide.runPythonAsync(`
                 import micropip
@@ -181,25 +178,24 @@ def test_install_custom_url(selenium_standalone_micropip, base_url):
             `);
             """
         )
-    finally:
-        target.unlink()
 
 
-def test_add_requirement(web_server_tst_data):
+def test_add_requirement():
     pytest.importorskip("packaging")
     from micropip import _micropip
 
-    server_hostname, server_port, server_log = web_server_tst_data
-    base_url = f"http://{server_hostname}:{server_port}/"
-    url = base_url + "snowballstemmer-2.0.0-py2.py3-none-any.whl"
+    with spawn_web_server(Path(__file__).parent / "test") as server:
+        server_hostname, server_port, _ = server
+        base_url = f"http://{server_hostname}:{server_port}/"
+        url = base_url + "snowballstemmer-2.0.0-py2.py3-none-any.whl"
 
-    transaction: dict[str, Any] = {
-        "wheels": [],
-        "locked": {},
-    }
-    asyncio.get_event_loop().run_until_complete(
-        _micropip.PACKAGE_MANAGER.add_requirement(url, {}, transaction)
-    )
+        transaction: dict[str, Any] = {
+            "wheels": [],
+            "locked": {},
+        }
+        asyncio.get_event_loop().run_until_complete(
+            _micropip.PACKAGE_MANAGER.add_requirement(url, {}, transaction)
+        )
 
     [name, req, version] = transaction["wheels"][0]
     assert name == "snowballstemmer"
diff --git a/packages/msgpack/test_pack.py b/packages/msgpack/test_pack.py
index bd2967f9d..351bb09ab 100644
--- a/packages/msgpack/test_pack.py
+++ b/packages/msgpack/test_pack.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(standalone=True, packages=["msgpack"])
diff --git a/packages/networkx/test_networkx.py b/packages/networkx/test_networkx.py
index 75c92d0aa..779906e85 100644
--- a/packages/networkx/test_networkx.py
+++ b/packages/networkx/test_networkx.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(standalone=True, packages=["networkx"])
diff --git a/packages/nlopt/test_nlopt.py b/packages/nlopt/test_nlopt.py
index a5e690195..d1c019207 100644
--- a/packages/nlopt/test_nlopt.py
+++ b/packages/nlopt/test_nlopt.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(
diff --git a/packages/numcodecs/test_numcodecs.py b/packages/numcodecs/test_numcodecs.py
index a4bc2b1bd..1c75fa38f 100644
--- a/packages/numcodecs/test_numcodecs.py
+++ b/packages/numcodecs/test_numcodecs.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(
diff --git a/packages/numpy/test_numpy.py b/packages/numpy/test_numpy.py
index 9705e520b..2ebe1593f 100644
--- a/packages/numpy/test_numpy.py
+++ b/packages/numpy/test_numpy.py
@@ -1,6 +1,5 @@
 import pytest
-
-from pyodide_build.testing import run_in_pyodide as run_in_pyodide_orig
+from pyodide_test_runner import run_in_pyodide as run_in_pyodide_orig
 
 
 def run_in_pyodide(**kwargs):
diff --git a/packages/opencv-python/test_opencv_python.py b/packages/opencv-python/test_opencv_python.py
index 7acf4d887..81979677a 100644
--- a/packages/opencv-python/test_opencv_python.py
+++ b/packages/opencv-python/test_opencv_python.py
@@ -1,7 +1,7 @@
 import base64
 import pathlib
 
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 REFERENCE_IMAGES_PATH = pathlib.Path(__file__).parent / "reference-images"
 
diff --git a/packages/python_solvespace/test_python_solvespace.py b/packages/python_solvespace/test_python_solvespace.py
index ce804c75f..9eb83310a 100644
--- a/packages/python_solvespace/test_python_solvespace.py
+++ b/packages/python_solvespace/test_python_solvespace.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["python_solvespace"])
diff --git a/packages/pywavelets/test_pywt.py b/packages/pywavelets/test_pywt.py
index 299c6cb14..5513b512b 100644
--- a/packages/pywavelets/test_pywt.py
+++ b/packages/pywavelets/test_pywt.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(
diff --git a/packages/regex/test_regex.py b/packages/regex/test_regex.py
index 6aa13178b..ce04de741 100644
--- a/packages/regex/test_regex.py
+++ b/packages/regex/test_regex.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["regex"])
diff --git a/packages/scikit-image/test_skimage.py b/packages/scikit-image/test_skimage.py
index aafc13136..4478f8f27 100644
--- a/packages/scikit-image/test_skimage.py
+++ b/packages/scikit-image/test_skimage.py
@@ -1,6 +1,6 @@
 import os
 
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 if "CI" in os.environ:
     xfail_browsers = {"chrome": "scikit-image takes too long to load in CI "}
diff --git a/packages/scikit-learn/test_scikit-learn.py b/packages/scikit-learn/test_scikit-learn.py
index acac4fd79..ad4ba04fe 100644
--- a/packages/scikit-learn/test_scikit-learn.py
+++ b/packages/scikit-learn/test_scikit-learn.py
@@ -1,6 +1,5 @@
 import pytest
-
-from conftest import selenium_context_manager
+from pyodide_test_runner.fixture import selenium_context_manager
 
 
 @pytest.mark.driver_timeout(40)
diff --git a/packages/scipy/test_scipy.py b/packages/scipy/test_scipy.py
index c1991c5b1..8afd42460 100644
--- a/packages/scipy/test_scipy.py
+++ b/packages/scipy/test_scipy.py
@@ -1,6 +1,6 @@
-from pyodide_build import testing
+from pyodide_test_runner import run_in_pyodide
 
-run_in_pyodide = testing.run_in_pyodide(
+run_in_pyodide_scipy = run_in_pyodide(
     module_scope=True,
     packages=["scipy"],
     # xfail_browsers={"chrome": "Times out in chrome"},
@@ -8,7 +8,7 @@ run_in_pyodide = testing.run_in_pyodide(
 )
 
 
-@run_in_pyodide
+@run_in_pyodide_scipy
 def test_scipy_linalg():
     import numpy as np
     import scipy.linalg
@@ -24,28 +24,28 @@ def test_scipy_linalg():
     assert_allclose(res, np.identity(N), rtol=1e-07, atol=1e-9)
 
 
-@run_in_pyodide
+@run_in_pyodide_scipy
 def test_brentq():
     from scipy.optimize import brentq
 
     brentq(lambda x: x, -1, 1)
 
 
-@run_in_pyodide
+@run_in_pyodide_scipy
 def test_dlamch():
     from scipy.linalg import lapack
 
     lapack.dlamch("Epsilon-Machine")
 
 
-@run_in_pyodide
+@run_in_pyodide_scipy
 def test_binom_ppf():
     from scipy.stats import binom
 
     assert binom.ppf(0.9, 1000, 0.1) == 112
 
 
-@testing.run_in_pyodide(module_scope=True, packages=["pytest", "scipy-tests"])
+@run_in_pyodide(module_scope=True, packages=["pytest", "scipy-tests"])
 def test_scipy_pytest():
     import pytest
 
diff --git a/packages/sharedlib-test-py/test_sharedlib.py b/packages/sharedlib-test-py/test_sharedlib.py
index 977ab6b05..d89dd8375 100644
--- a/packages/sharedlib-test-py/test_sharedlib.py
+++ b/packages/sharedlib-test-py/test_sharedlib.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["sharedlib-test-py"])
diff --git a/packages/sqlalchemy/test_sqlalchemy.py b/packages/sqlalchemy/test_sqlalchemy.py
index 97c2cfd64..eada96aa9 100644
--- a/packages/sqlalchemy/test_sqlalchemy.py
+++ b/packages/sqlalchemy/test_sqlalchemy.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["sqlalchemy"])
diff --git a/packages/ssl/test_ssl.py b/packages/ssl/test_ssl.py
index e05ebc9cd..13afffee5 100644
--- a/packages/ssl/test_ssl.py
+++ b/packages/ssl/test_ssl.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["test", "ssl"])
diff --git a/packages/sympy/test_sympy.py b/packages/sympy/test_sympy.py
index 7ea57873c..c8e23e044 100644
--- a/packages/sympy/test_sympy.py
+++ b/packages/sympy/test_sympy.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["sympy"])
diff --git a/packages/test_packages_common.py b/packages/test_packages_common.py
index fa1498ec1..f72d3a187 100644
--- a/packages/test_packages_common.py
+++ b/packages/test_packages_common.py
@@ -3,7 +3,7 @@ import os
 
 import pytest
 
-from conftest import ROOT_PATH, _package_is_built
+from conftest import ROOT_PATH, package_is_built
 from pyodide_build.io import parse_package_config
 
 PKG_DIR = ROOT_PATH / "packages"
@@ -44,7 +44,7 @@ def test_parse_package(name):
 @pytest.mark.driver_timeout(60)
 @pytest.mark.parametrize("name", registered_packages())
 def test_import(name, selenium_standalone):
-    if not _package_is_built(name):
+    if not package_is_built(name):
         raise AssertionError(
             "Implementation error. Test for an unbuilt package "
             "should have been skipped in selenium_standalone fixture"
diff --git a/packages/wrapt/test_wrapt.py b/packages/wrapt/test_wrapt.py
index ed967d086..180a7ade2 100644
--- a/packages/wrapt/test_wrapt.py
+++ b/packages/wrapt/test_wrapt.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["wrapt"])
diff --git a/packages/zarr/test_zarr.py b/packages/zarr/test_zarr.py
index f9244e003..ba645e95c 100644
--- a/packages/zarr/test_zarr.py
+++ b/packages/zarr/test_zarr.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide(packages=["numpy", "numcodecs", "zarr"])
diff --git a/pyodide-build/pyodide_build/tests/test_testing.py b/pyodide-build/pyodide_build/tests/test_testing.py
deleted file mode 100644
index 7bf9de06b..000000000
--- a/pyodide-build/pyodide_build/tests/test_testing.py
+++ /dev/null
@@ -1,16 +0,0 @@
-from pyodide_build.testing import set_webdriver_script_timeout
-
-
-class _MockSelenium:
-    script_timeout = 2
-
-    def set_script_timeout(self, value):
-        self._timeout = value
-
-
-def test_set_webdriver_script_timeout():
-    selenium = _MockSelenium()
-    assert not hasattr(selenium, "_timeout")
-    with set_webdriver_script_timeout(selenium, script_timeout=10):
-        assert selenium._timeout == 10
-    assert selenium._timeout == 2
diff --git a/pyodide-test-runner/pyodide_test_runner/__init__.py b/pyodide-test-runner/pyodide_test_runner/__init__.py
new file mode 100644
index 000000000..031985821
--- /dev/null
+++ b/pyodide-test-runner/pyodide_test_runner/__init__.py
@@ -0,0 +1,16 @@
+from .browser import ChromeWrapper, FirefoxWrapper, NodeWrapper, SeleniumWrapper
+from .decorator import run_in_pyodide
+from .fixture import *  # noqa: F403, F401
+from .server import spawn_web_server
+from .utils import parse_driver_timeout, set_webdriver_script_timeout
+
+__all__ = [
+    "SeleniumWrapper",
+    "FirefoxWrapper",
+    "ChromeWrapper",
+    "NodeWrapper",
+    "set_webdriver_script_timeout",
+    "parse_driver_timeout",
+    "run_in_pyodide",
+    "spawn_web_server",
+]
diff --git a/pyodide-test-runner/pyodide_test_runner/browser.py b/pyodide-test-runner/pyodide_test_runner/browser.py
new file mode 100644
index 000000000..18498423f
--- /dev/null
+++ b/pyodide-test-runner/pyodide_test_runner/browser.py
@@ -0,0 +1,462 @@
+import json
+import textwrap
+from pathlib import Path
+
+import pexpect
+
+TEST_SETUP_CODE = """
+Error.stackTraceLimit = Infinity;
+
+// Fix globalThis is messed up in firefox see facebook/react#16606.
+// Replace it with window.
+globalThis.globalThis = globalThis.window || globalThis;
+
+globalThis.sleep = function (s) {
+    return new Promise((resolve) => setTimeout(resolve, s));
+};
+
+globalThis.assert = function (cb, message = "") {
+    if (message !== "") {
+        message = "\\n" + message;
+    }
+    if (cb() !== true) {
+        throw new Error(
+            `Assertion failed: ${cb.toString().slice(6)}${message}`
+        );
+    }
+};
+
+globalThis.assertAsync = async function (cb, message = "") {
+    if (message !== "") {
+        message = "\\n" + message;
+    }
+    if ((await cb()) !== true) {
+        throw new Error(
+            `Assertion failed: ${cb.toString().slice(12)}${message}`
+        );
+    }
+};
+
+function checkError(err, errname, pattern, pat_str, thiscallstr) {
+    if (typeof pattern === "string") {
+        pattern = new RegExp(pattern);
+    }
+    if (!err) {
+        throw new Error(`${thiscallstr} failed, no error thrown`);
+    }
+    if (err.constructor.name !== errname) {
+        throw new Error(
+            `${thiscallstr} failed, expected error ` +
+                `of type '${errname}' got type '${err.constructor.name}'`
+        );
+    }
+    if (!pattern.test(err.message)) {
+        throw new Error(
+            `${thiscallstr} failed, expected error ` +
+                `message to match pattern ${pat_str} got:\n${err.message}`
+        );
+    }
+}
+
+globalThis.assertThrows = function (cb, errname, pattern) {
+    let pat_str = typeof pattern === "string" ? `"${pattern}"` : `${pattern}`;
+    let thiscallstr = `assertThrows(${cb.toString()}, "${errname}", ${pat_str})`;
+    let err = undefined;
+    try {
+        cb();
+    } catch (e) {
+        err = e;
+    }
+    checkError(err, errname, pattern, pat_str, thiscallstr);
+};
+
+globalThis.assertThrowsAsync = async function (cb, errname, pattern) {
+    let pat_str = typeof pattern === "string" ? `"${pattern}"` : `${pattern}`;
+    let thiscallstr = `assertThrowsAsync(${cb.toString()}, "${errname}", ${pat_str})`;
+    let err = undefined;
+    try {
+        await cb();
+    } catch (e) {
+        err = e;
+    }
+    checkError(err, errname, pattern, pat_str, thiscallstr);
+};
+""".strip()
+
+
+class JavascriptException(Exception):
+    def __init__(self, msg, stack):
+        self.msg = msg
+        self.stack = stack
+        # In chrome the stack contains the message
+        if self.stack and self.stack.startswith(self.msg):
+            self.msg = ""
+
+    def __str__(self):
+        return "\n\n".join(x for x in [self.msg, self.stack] if x)
+
+
+class SeleniumWrapper:
+    JavascriptException = JavascriptException
+
+    def __init__(
+        self,
+        server_port,
+        server_hostname="127.0.0.1",
+        server_log=None,
+        load_pyodide=True,
+        script_timeout=20,
+        script_type="classic",
+        dist_dir=None,
+    ):
+        self.server_port = server_port
+        self.server_hostname = server_hostname
+        self.base_url = f"http://{self.server_hostname}:{self.server_port}"
+        self.server_log = server_log
+        self.script_type = script_type
+        self.dist_dir = dist_dir
+        self.driver = self.get_driver()  # type: ignore[attr-defined]
+        self.set_script_timeout(script_timeout)
+        self.script_timeout = script_timeout
+        self.prepare_driver()
+        self.javascript_setup()
+        if load_pyodide:
+            self.load_pyodide()
+            self.initialize_global_hiwire_objects()
+            self.save_state()
+            self.restore_state()
+
+    def prepare_driver(self):
+        if self.script_type == "classic":
+            self.driver.get(f"{self.base_url}/test.html")
+        elif self.script_type == "module":
+            self.driver.get(f"{self.base_url}/module_test.html")
+        else:
+            raise Exception("Unknown script type to load!")
+
+    def set_script_timeout(self, timeout):
+        self.driver.set_script_timeout(timeout)
+
+    def quit(self):
+        self.driver.quit()
+
+    def refresh(self):
+        self.driver.refresh()
+        self.javascript_setup()
+
+    def javascript_setup(self):
+        self.run_js(
+            TEST_SETUP_CODE,
+            pyodide_checks=False,
+        )
+
+    def load_pyodide(self):
+        self.run_js(
+            """
+            let pyodide = await loadPyodide({ fullStdLib: false, jsglobals : self });
+            self.pyodide = pyodide;
+            globalThis.pyodide = pyodide;
+            pyodide._api.inTestHoist = true; // improve some error messages for tests
+            """
+        )
+
+    def initialize_global_hiwire_objects(self):
+        """
+        There are a bunch of global objects that occasionally enter the hiwire cache
+        but never leave. The refcount checks get angry about them if they aren't preloaded.
+        We need to go through and touch them all once to keep everything okay.
+        """
+        self.run_js(
+            """
+            pyodide.globals.get;
+            pyodide.pyodide_py.eval_code;
+            pyodide.pyodide_py.eval_code_async;
+            pyodide.pyodide_py.register_js_module;
+            pyodide.pyodide_py.unregister_js_module;
+            pyodide.pyodide_py.find_imports;
+            pyodide._api.importlib.invalidate_caches;
+            pyodide._api.package_loader.unpack_buffer;
+            pyodide._api.package_loader.get_dynlibs;
+            pyodide.runPython("");
+            """
+        )
+
+    @property
+    def pyodide_loaded(self):
+        return self.run_js("return !!(self.pyodide && self.pyodide.runPython);")
+
+    @property
+    def logs(self):
+        logs = self.run_js("return self.logs;", pyodide_checks=False)
+        if logs is not None:
+            return "\n".join(str(x) for x in logs)
+        return ""
+
+    def clean_logs(self):
+        self.run_js("self.logs = []", pyodide_checks=False)
+
+    def run(self, code):
+        return self.run_js(
+            f"""
+            let result = pyodide.runPython({code!r});
+            if(result && result.toJs){{
+                let converted_result = result.toJs();
+                if(pyodide.isPyProxy(converted_result)){{
+                    converted_result = undefined;
+                }}
+                result.destroy();
+                return converted_result;
+            }}
+            return result;
+            """
+        )
+
+    def run_async(self, code):
+        return self.run_js(
+            f"""
+            await pyodide.loadPackagesFromImports({code!r})
+            let result = await pyodide.runPythonAsync({code!r});
+            if(result && result.toJs){{
+                let converted_result = result.toJs();
+                if(pyodide.isPyProxy(converted_result)){{
+                    converted_result = undefined;
+                }}
+                result.destroy();
+                return converted_result;
+            }}
+            return result;
+            """
+        )
+
+    def run_js(self, code, pyodide_checks=True):
+        """Run JavaScript code and check for pyodide errors"""
+        if isinstance(code, str) and code.startswith("\n"):
+            # we have a multiline string, fix indentation
+            code = textwrap.dedent(code)
+
+        if pyodide_checks:
+            check_code = """
+                    if(globalThis.pyodide && pyodide._module && pyodide._module._PyErr_Occurred()){
+                        try {
+                            pyodide._module._pythonexc2js();
+                        } catch(e){
+                            console.error(`Python exited with error flag set! Error was:\n${e.message}`);
+                            // Don't put original error message in new one: we want
+                            // "pytest.raises(xxx, match=msg)" to fail
+                            throw new Error(`Python exited with error flag set!`);
+                        }
+                    }
+           """
+        else:
+            check_code = ""
+        return self.run_js_inner(code, check_code)
+
+    def run_js_inner(self, code, check_code):
+        wrapper = """
+            let cb = arguments[arguments.length - 1];
+            let run = async () => { %s }
+            (async () => {
+                try {
+                    let result = await run();
+                    %s
+                    cb([0, result]);
+                } catch (e) {
+                    cb([1, e.toString(), e.stack, e.message]);
+                }
+            })()
+        """
+        retval = self.driver.execute_async_script(wrapper % (code, check_code))
+        if retval[0] == 0:
+            return retval[1]
+        else:
+            print("JavascriptException message: ", retval[3])
+            raise JavascriptException(retval[1], retval[2])
+
+    def get_num_hiwire_keys(self):
+        return self.run_js("return pyodide._module.hiwire.num_keys();")
+
+    @property
+    def force_test_fail(self) -> bool:
+        return self.run_js("return !!pyodide._api.fail_test;")
+
+    def clear_force_test_fail(self):
+        self.run_js("pyodide._api.fail_test = false;")
+
+    def save_state(self):
+        self.run_js("self.__savedState = pyodide._api.saveState();")
+
+    def restore_state(self):
+        self.run_js(
+            """
+            if(self.__savedState){
+                pyodide._api.restoreState(self.__savedState)
+            }
+            """
+        )
+
+    def get_num_proxies(self):
+        return self.run_js("return pyodide._module.pyproxy_alloc_map.size")
+
+    def enable_pyproxy_tracing(self):
+        self.run_js("pyodide._module.enable_pyproxy_allocation_tracing()")
+
+    def disable_pyproxy_tracing(self):
+        self.run_js("pyodide._module.disable_pyproxy_allocation_tracing()")
+
+    def run_webworker(self, code):
+        if isinstance(code, str) and code.startswith("\n"):
+            # we have a multiline string, fix indentation
+            code = textwrap.dedent(code)
+
+        worker_file = (
+            "webworker_dev.js"
+            if self.script_type == "classic"
+            else "module_webworker_dev.js"
+        )
+
+        return self.run_js(
+            """
+            let worker = new Worker('{}', {{ type: '{}' }});
+            let res = new Promise((res, rej) => {{
+                worker.onerror = e => rej(e);
+                worker.onmessage = e => {{
+                    if (e.data.results) {{
+                       res(e.data.results);
+                    }} else {{
+                       rej(e.data.error);
+                    }}
+                }};
+                worker.postMessage({{ python: {!r} }});
+            }});
+            return await res
+            """.format(
+                f"http://{self.server_hostname}:{self.server_port}/{worker_file}",
+                self.script_type,
+                code,
+            ),
+            pyodide_checks=False,
+        )
+
+    def load_package(self, packages):
+        self.run_js(f"await pyodide.loadPackage({packages!r})")
+
+    @property
+    def urls(self):
+        for handle in self.driver.window_handles:
+            self.driver.switch_to.window(handle)
+            yield self.driver.current_url
+
+
+class FirefoxWrapper(SeleniumWrapper):
+
+    browser = "firefox"
+
+    def get_driver(self):
+        from selenium.webdriver import Firefox
+        from selenium.webdriver.firefox.options import Options
+
+        options = Options()
+        options.add_argument("--headless")
+
+        return Firefox(executable_path="geckodriver", options=options)
+
+
+class ChromeWrapper(SeleniumWrapper):
+
+    browser = "chrome"
+
+    def get_driver(self):
+        from selenium.webdriver import Chrome
+        from selenium.webdriver.chrome.options import Options
+
+        options = Options()
+        options.add_argument("--headless")
+        options.add_argument("--no-sandbox")
+        options.add_argument("--js-flags=--expose-gc")
+        return Chrome(options=options)
+
+    def collect_garbage(self):
+        self.driver.execute_cdp_cmd("HeapProfiler.collectGarbage", {})
+
+
+class NodeWrapper(SeleniumWrapper):
+    browser = "node"
+
+    def init_node(self):
+        curdir = Path(__file__).parent
+        self.p = pexpect.spawn("/bin/bash", timeout=60)
+        self.p.setecho(False)
+        self.p.delaybeforesend = None
+        # disable canonical input processing mode to allow sending longer lines
+        # See: https://pexpect.readthedocs.io/en/stable/api/pexpect.html#pexpect.spawn.send
+        self.p.sendline("stty -icanon")
+        self.p.sendline(
+            f"node --expose-gc --experimental-wasm-bigint {curdir}/node_test_driver.js {self.base_url} {self.dist_dir}",
+        )
+
+        try:
+            self.p.expect_exact("READY!!")
+        except pexpect.exceptions.EOF:
+            raise JavascriptException("", self.p.before.decode())
+
+    def get_driver(self):
+        self._logs = []
+        self.init_node()
+
+        class NodeDriver:
+            def __getattr__(self, x):
+                raise NotImplementedError()
+
+        return NodeDriver()
+
+    def prepare_driver(self):
+        pass
+
+    def set_script_timeout(self, timeout):
+        self._timeout = timeout
+
+    def quit(self):
+        self.p.sendeof()
+
+    def refresh(self):
+        self.quit()
+        self.init_node()
+        self.javascript_setup()
+
+    def collect_garbage(self):
+        self.run_js("gc()")
+
+    @property
+    def logs(self):
+        return "\n".join(self._logs)
+
+    def clean_logs(self):
+        self._logs = []
+
+    def run_js_inner(self, code, check_code):
+        check_code = ""
+        wrapped = """
+            let result = await (async () => {{ {} }})();
+            {}
+            return result;
+        """.format(
+            code,
+            check_code,
+        )
+        from uuid import uuid4
+
+        cmd_id = str(uuid4())
+        self.p.sendline(cmd_id)
+        self.p.sendline(wrapped)
+        self.p.sendline(cmd_id)
+        self.p.expect_exact(f"{cmd_id}:UUID\r\n", timeout=self._timeout)
+        self.p.expect_exact(f"{cmd_id}:UUID\r\n")
+        if self.p.before:
+            self._logs.append(self.p.before.decode()[:-2].replace("\r", ""))
+        self.p.expect("[01]\r\n")
+        success = int(self.p.match[0].decode()[0]) == 0
+        self.p.expect_exact(f"\r\n{cmd_id}:UUID\r\n")
+        if success:
+            return json.loads(self.p.before.decode().replace("undefined", "null"))
+        else:
+            raise JavascriptException("", self.p.before.decode())
diff --git a/pyodide-build/pyodide_build/testing.py b/pyodide-test-runner/pyodide_test_runner/decorator.py
similarity index 81%
rename from pyodide-build/pyodide_build/testing.py
rename to pyodide-test-runner/pyodide_test_runner/decorator.py
index 6c21d74fa..e69c005a3 100644
--- a/pyodide-build/pyodide_build/testing.py
+++ b/pyodide-test-runner/pyodide_test_runner/decorator.py
@@ -1,29 +1,11 @@
-import contextlib
 import inspect
 from base64 import b64encode
+from pprint import pformat
 from typing import Callable, Collection
 
 import pytest
 
-
-def _run_in_pyodide_get_source(f):
-    lines, start_line = inspect.getsourcelines(f)
-    num_decorator_lines = 0
-    for line in lines:
-        if line.startswith("def") or line.startswith("async def"):
-            break
-        num_decorator_lines += 1
-    start_line += num_decorator_lines - 1
-    # Remove first line, which is the decorator. Then pad with empty lines to fix line number.
-    lines = ["\n"] * start_line + lines[num_decorator_lines:]
-    return "".join(lines)
-
-
-def chunkstring(string, length):
-    return (string[0 + i : length + i] for i in range(0, len(string), length))
-
-
-from pprint import pformat
+from .utils import set_webdriver_script_timeout
 
 
 def run_in_pyodide(
@@ -77,7 +59,7 @@ def run_in_pyodide(
                     source = _run_in_pyodide_get_source(f)
                     filename = inspect.getsourcefile(f)
                     encoded = pformat(
-                        list(chunkstring(b64encode(source.encode()).decode(), 100))
+                        list(_chunkstring(b64encode(source.encode()).decode(), 100))
                     )
 
                     selenium.run_js(
@@ -128,29 +110,18 @@ def run_in_pyodide(
         return decorator
 
 
-@contextlib.contextmanager
-def set_webdriver_script_timeout(selenium, script_timeout: float | None):
-    """Set selenium script timeout
-
-    Parameters
-    ----------
-    selenum : SeleniumWrapper
-       a SeleniumWrapper wrapper instance
-    script_timeout : int | float
-       value of the timeout in seconds
-    """
-    if script_timeout is not None:
-        selenium.set_script_timeout(script_timeout)
-    yield
-    # revert to the initial value
-    if script_timeout is not None:
-        selenium.set_script_timeout(selenium.script_timeout)
+def _chunkstring(string, length):
+    return (string[0 + i : length + i] for i in range(0, len(string), length))
 
 
-def parse_driver_timeout(request) -> float | None:
-    """Parse driver timeout value from pytest request object"""
-    mark = request.node.get_closest_marker("driver_timeout")
-    if mark is None:
-        return None
-    else:
-        return mark.args[0]
+def _run_in_pyodide_get_source(f):
+    lines, start_line = inspect.getsourcelines(f)
+    num_decorator_lines = 0
+    for line in lines:
+        if line.startswith("def") or line.startswith("async def"):
+            break
+        num_decorator_lines += 1
+    start_line += num_decorator_lines - 1
+    # Remove first line, which is the decorator. Then pad with empty lines to fix line number.
+    lines = ["\n"] * start_line + lines[num_decorator_lines:]
+    return "".join(lines)
diff --git a/pyodide-test-runner/pyodide_test_runner/fixture.py b/pyodide-test-runner/pyodide_test_runner/fixture.py
new file mode 100644
index 000000000..870d0443d
--- /dev/null
+++ b/pyodide-test-runner/pyodide_test_runner/fixture.py
@@ -0,0 +1,149 @@
+import contextlib
+
+import pytest
+
+from .browser import ChromeWrapper, FirefoxWrapper, NodeWrapper, SeleniumWrapper
+from .server import spawn_web_server
+from .utils import parse_driver_timeout, set_webdriver_script_timeout
+
+
+@contextlib.contextmanager
+def selenium_common(request, web_server_main, load_pyodide=True, script_type="classic"):
+    """Returns an initialized selenium object.
+
+    If `_should_skip_test` indicate that the test will be skipped,
+    return None, as initializing Pyodide for selenium is expensive
+    """
+
+    server_hostname, server_port, server_log = web_server_main
+    cls: type[SeleniumWrapper]
+    if request.param == "firefox":
+        cls = FirefoxWrapper
+    elif request.param == "chrome":
+        cls = ChromeWrapper
+    elif request.param == "node":
+        cls = NodeWrapper
+    else:
+        raise AssertionError(f"Unknown browser: {request.param}")
+
+    dist_dir = request.config.getoption("--dist-dir")
+    selenium = cls(
+        server_port=server_port,
+        server_hostname=server_hostname,
+        server_log=server_log,
+        load_pyodide=load_pyodide,
+        script_type=script_type,
+        dist_dir=dist_dir,
+    )
+    try:
+        yield selenium
+    finally:
+        selenium.quit()
+
+
+@pytest.fixture(params=["firefox", "chrome", "node"], scope="function")
+def selenium_standalone(request, web_server_main):
+    with selenium_common(request, web_server_main) as selenium:
+        with set_webdriver_script_timeout(
+            selenium, script_timeout=parse_driver_timeout(request)
+        ):
+            try:
+                yield selenium
+            finally:
+                print(selenium.logs)
+
+
+@pytest.fixture(params=["firefox", "chrome", "node"], scope="module")
+def selenium_esm(request, web_server_main):
+    with selenium_common(
+        request, web_server_main, load_pyodide=True, script_type="module"
+    ) as selenium:
+        with set_webdriver_script_timeout(
+            selenium, script_timeout=parse_driver_timeout(request)
+        ):
+            try:
+                yield selenium
+            finally:
+                print(selenium.logs)
+
+
+@contextlib.contextmanager
+def selenium_standalone_noload_common(request, web_server_main, script_type="classic"):
+    with selenium_common(
+        request, web_server_main, load_pyodide=False, script_type=script_type
+    ) as selenium:
+        with set_webdriver_script_timeout(
+            selenium, script_timeout=parse_driver_timeout(request)
+        ):
+            try:
+                yield selenium
+            finally:
+                print(selenium.logs)
+
+
+@pytest.fixture(params=["firefox", "chrome"], scope="function")
+def selenium_webworker_standalone(request, web_server_main, script_type):
+    # Avoid loading the fixture if the test is going to be skipped
+    if request.param == "firefox" and script_type == "module":
+        pytest.skip("firefox does not support module type web worker")
+
+    with selenium_standalone_noload_common(
+        request, web_server_main, script_type=script_type
+    ) as selenium:
+        yield selenium
+
+
+@pytest.fixture(params=["classic", "module"], scope="module")
+def script_type(request):
+    return request.param
+
+
+@pytest.fixture(params=["firefox", "chrome", "node"], scope="function")
+def selenium_standalone_noload(request, web_server_main):
+    """Only difference between this and selenium_webworker_standalone is that
+    this also tests on node."""
+
+    with selenium_standalone_noload_common(request, web_server_main) as selenium:
+        yield selenium
+
+
+# selenium instance cached at the module level
+@pytest.fixture(params=["firefox", "chrome", "node"], scope="module")
+def selenium_module_scope(request, web_server_main):
+    with selenium_common(request, web_server_main) as selenium:
+        yield selenium
+
+
+# Hypothesis is unhappy with function scope fixtures. Instead, use the
+# module scope fixture `selenium_module_scope` and use:
+# `with selenium_context_manager(selenium_module_scope) as selenium`
+@contextlib.contextmanager
+def selenium_context_manager(selenium_module_scope):
+    try:
+        selenium_module_scope.clean_logs()
+        yield selenium_module_scope
+    finally:
+        print(selenium_module_scope.logs)
+
+
+@pytest.fixture
+def selenium(request, selenium_module_scope):
+    with selenium_context_manager(selenium_module_scope) as selenium:
+        with set_webdriver_script_timeout(
+            selenium, script_timeout=parse_driver_timeout(request)
+        ):
+            yield selenium
+
+
+@pytest.fixture(scope="session")
+def web_server_main(request):
+    """Web server that serves files in the dist directory"""
+    with spawn_web_server(request.config.option.dist_dir) as output:
+        yield output
+
+
+@pytest.fixture(scope="session")
+def web_server_secondary(request):
+    """Secondary web server that serves files dist directory"""
+    with spawn_web_server(request.config.option.dist_dir) as output:
+        yield output
diff --git a/src/test-js/node_test_driver.js b/pyodide-test-runner/pyodide_test_runner/node_test_driver.js
similarity index 91%
rename from src/test-js/node_test_driver.js
rename to pyodide-test-runner/pyodide_test_runner/node_test_driver.js
index f5ccac613..31be17cf9 100644
--- a/src/test-js/node_test_driver.js
+++ b/pyodide-test-runner/pyodide_test_runner/node_test_driver.js
@@ -5,11 +5,14 @@ const util = require("util");
 const node_fetch = require("node-fetch");
 const base64 = require("base-64");
 
-let { loadPyodide } = require("pyodide");
-let base_url = process.argv[2];
+let baseUrl = process.argv[2];
+let distDir = process.argv[3];
+
+let { loadPyodide } = require(`${distDir}/pyodide`);
+
 // node requires full paths.
 function fetch(path) {
-  return node_fetch(new URL(path, base_url).toString());
+  return node_fetch(new URL(path, baseUrl).toString());
 }
 
 const context = {
diff --git a/pyodide-test-runner/pyodide_test_runner/server.py b/pyodide-test-runner/pyodide_test_runner/server.py
new file mode 100644
index 000000000..d34cf8393
--- /dev/null
+++ b/pyodide-test-runner/pyodide_test_runner/server.py
@@ -0,0 +1,82 @@
+import contextlib
+import http.server
+import multiprocessing
+import os
+import pathlib
+import queue
+import shutil
+import socketserver
+import sys
+import tempfile
+
+
+@contextlib.contextmanager
+def spawn_web_server(dist_dir):
+
+    tmp_dir = tempfile.mkdtemp()
+    log_path = pathlib.Path(tmp_dir) / "http-server.log"
+    q: multiprocessing.Queue[str] = multiprocessing.Queue()
+    p = multiprocessing.Process(target=run_web_server, args=(q, log_path, dist_dir))
+
+    try:
+        p.start()
+        port = q.get()
+        hostname = "127.0.0.1"
+
+        print(
+            f"Spawning webserver at http://{hostname}:{port} "
+            f"(see logs in {log_path})"
+        )
+        yield hostname, port, log_path
+    finally:
+        q.put("TERMINATE")
+        p.join()
+        shutil.rmtree(tmp_dir)
+
+
+def run_web_server(q, log_filepath, dist_dir):
+    """Start the HTTP web server
+
+    Parameters
+    ----------
+    q : Queue
+      communication queue
+    log_path : pathlib.Path
+      path to the file where to store the logs
+    """
+
+    os.chdir(dist_dir)
+
+    log_fh = log_filepath.open("w", buffering=1)
+    sys.stdout = log_fh
+    sys.stderr = log_fh
+
+    class Handler(http.server.SimpleHTTPRequestHandler):
+        def log_message(self, format_, *args):
+            print(
+                "[%s] source: %s:%s - %s"
+                % (self.log_date_time_string(), *self.client_address, format_ % args)
+            )
+
+        def end_headers(self):
+            # Enable Cross-Origin Resource Sharing (CORS)
+            self.send_header("Access-Control-Allow-Origin", "*")
+            super().end_headers()
+
+    with socketserver.TCPServer(("", 0), Handler) as httpd:
+        host, port = httpd.server_address
+        print(f"Starting webserver at http://{host}:{port}")
+        httpd.server_name = "test-server"  # type: ignore[attr-defined]
+        httpd.server_port = port  # type: ignore[attr-defined]
+        q.put(port)
+
+        def service_actions():
+            try:
+                if q.get(False) == "TERMINATE":
+                    print("Stopping server...")
+                    sys.exit(0)
+            except queue.Empty:
+                pass
+
+        httpd.service_actions = service_actions  # type: ignore[assignment]
+        httpd.serve_forever()
diff --git a/src/tests/test_testing.py b/pyodide-test-runner/pyodide_test_runner/tests/test_testing.py
similarity index 96%
rename from src/tests/test_testing.py
rename to pyodide-test-runner/pyodide_test_runner/tests/test_testing.py
index d1ce88fba..1bb9fe086 100644
--- a/src/tests/test_testing.py
+++ b/pyodide-test-runner/pyodide_test_runner/tests/test_testing.py
@@ -1,7 +1,8 @@
 import pathlib
 from textwrap import dedent
 
-from pyodide_build.testing import _run_in_pyodide_get_source, run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
+from pyodide_test_runner.decorator import _run_in_pyodide_get_source
 
 
 def test_web_server_secondary(selenium, web_server_secondary):
@@ -89,7 +90,6 @@ def test_assert(selenium):
         let threw;
         assertThrows(() => { throw new TypeError("aaabbbccc") }, "TypeError", "bbc");
         assertThrows(() => { throw new TypeError("aaabbbccc") }, "TypeError", /.{3}.{3}.{3}/);
-
         threw = false;
         try {
             assertThrows(() => 0, "TypeError", /.*/);
@@ -98,7 +98,6 @@ def test_assert(selenium):
             assert(() => e.message == `assertThrows(() => 0, "TypeError", /.*/) failed, no error thrown`, e.message);
         }
         assert(() => threw);
-
         threw = false;
         try {
             assertThrows(() => { throw new ReferenceError("blah"); }, "TypeError", /.*/);
@@ -107,7 +106,6 @@ def test_assert(selenium):
             assert(() => e.message.endsWith("expected error of type 'TypeError' got type 'ReferenceError'"));
         }
         assert(() => threw);
-
         threw = false;
         try {
             assertThrows(() => { throw new TypeError("blah"); }, "TypeError", "abcd");
@@ -117,7 +115,6 @@ def test_assert(selenium):
             assert(() => e.message.endsWith(`expected error message to match pattern "abcd" got:\nblah`));
         }
         assert(() => threw);
-
         threw = false;
         try {
             assertThrows(() => { throw new TypeError("blah"); }, "TypeError", /a..d/);
diff --git a/pyodide-test-runner/pyodide_test_runner/utils.py b/pyodide-test-runner/pyodide_test_runner/utils.py
new file mode 100644
index 000000000..c4896ec10
--- /dev/null
+++ b/pyodide-test-runner/pyodide_test_runner/utils.py
@@ -0,0 +1,93 @@
+import contextlib
+import functools
+import json
+import re
+from pathlib import Path
+
+import pytest
+
+
+@contextlib.contextmanager
+def set_webdriver_script_timeout(selenium, script_timeout: float | None):
+    """Set selenium script timeout
+
+    Parameters
+    ----------
+    selenum : SeleniumWrapper
+       a SeleniumWrapper wrapper instance
+    script_timeout : int | float
+       value of the timeout in seconds
+    """
+    if script_timeout is not None:
+        selenium.set_script_timeout(script_timeout)
+    yield
+    # revert to the initial value
+    if script_timeout is not None:
+        selenium.set_script_timeout(selenium.script_timeout)
+
+
+def parse_driver_timeout(request) -> float | None:
+    """Parse driver timeout value from pytest request object"""
+    mark = request.node.get_closest_marker("driver_timeout")
+    if mark is None:
+        return None
+    else:
+        return mark.args[0]
+
+
+def maybe_skip_test(item, dist_dir, delayed=False):
+    """If necessary skip test at the fixture level, to avoid
+
+    loading the selenium_standalone fixture which takes a long time.
+    """
+    skip_msg = None
+    # Testing a package. Skip the test if the package is not built.
+    match = re.match(
+        r".*/packages/(?P<name>[\w\-]+)/test_[\w\-]+\.py", str(item.parent.fspath)
+    )
+    if match:
+        package_name = match.group("name")
+        if not package_is_built(package_name, dist_dir):
+            skip_msg = f"package '{package_name}' is not built."
+
+    # Common package import test. Skip it if the package is not built.
+    if (
+        skip_msg is None
+        and str(item.fspath).endswith("test_packages_common.py")
+        and item.name.startswith("test_import")
+    ):
+        match = re.match(
+            r"test_import\[(firefox|chrome|node)-(?P<name>[\w-]+)\]", item.name
+        )
+        if match:
+            package_name = match.group("name")
+            if not package_is_built(package_name, dist_dir):
+                # If the test is going to be skipped remove the
+                # selenium_standalone as it takes a long time to initialize
+                skip_msg = f"package '{package_name}' is not built."
+        else:
+            raise AssertionError(
+                f"Couldn't parse package name from {item.name}. This should not happen!"
+            )
+
+    # TODO: also use this hook to skip doctests we cannot run (or run them
+    # inside the selenium wrapper)
+
+    if skip_msg is not None:
+        if delayed:
+            item.add_marker(pytest.mark.skip(reason=skip_msg))
+        else:
+            pytest.skip(skip_msg)
+
+
+@functools.cache
+def built_packages(dist_dir: Path) -> list[str]:
+    """Returns the list of built package names from packages.json"""
+    packages_json_path = dist_dir / "packages.json"
+    if not packages_json_path.exists():
+        return []
+    return list(json.loads(packages_json_path.read_text())["packages"].keys())
+
+
+def package_is_built(package_name: str, dist_dir: Path) -> bool:
+    return package_name.lower() in built_packages(dist_dir)
diff --git a/src/tests/test_bz2.py b/src/tests/test_bz2.py
index 551171ddf..73d0ed29d 100644
--- a/src/tests/test_bz2.py
+++ b/src/tests/test_bz2.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide
diff --git a/src/tests/test_console.py b/src/tests/test_console.py
index 12ea8efd6..82101739f 100644
--- a/src/tests/test_console.py
+++ b/src/tests/test_console.py
@@ -3,11 +3,11 @@ import sys
 import time
 
 import pytest
+from pyodide_test_runner import run_in_pyodide
+from pyodide_test_runner.fixture import selenium_common
 
-from conftest import selenium_common
 from pyodide import CodeRunner, console  # noqa: E402
 from pyodide.console import Console, _CommandCompiler, _Compile  # noqa: E402
-from pyodide_build.testing import run_in_pyodide
 
 
 def test_command_compiler():
diff --git a/src/tests/test_jsproxy.py b/src/tests/test_jsproxy.py
index b8b847256..4687f63b9 100644
--- a/src/tests/test_jsproxy.py
+++ b/src/tests/test_jsproxy.py
@@ -1,7 +1,6 @@
 # See also test_typeconversions, and test_python.
 import pytest
-
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 def test_jsproxy_dir(selenium):
diff --git a/src/tests/test_pyodide.py b/src/tests/test_pyodide.py
index 96b0a75ad..ae7829083 100644
--- a/src/tests/test_pyodide.py
+++ b/src/tests/test_pyodide.py
@@ -3,9 +3,9 @@ from textwrap import dedent
 from typing import Any, Sequence
 
 import pytest
+from pyodide_test_runner import run_in_pyodide
 
 from pyodide import CodeRunner, eval_code, find_imports, should_quiet  # noqa: E402
-from pyodide_build.testing import run_in_pyodide
 
 
 def _strip_assertions_stderr(messages: Sequence[str]) -> list[str]:
diff --git a/src/tests/test_pyodide_http.py b/src/tests/test_pyodide_http.py
index 62cbe5e2a..69bfe5229 100644
--- a/src/tests/test_pyodide_http.py
+++ b/src/tests/test_pyodide_http.py
@@ -1,6 +1,5 @@
 import pytest
-
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 def test_open_url(selenium, httpserver):
diff --git a/src/tests/test_sqlite3.py b/src/tests/test_sqlite3.py
index eaeab2aba..3a4b4db92 100644
--- a/src/tests/test_sqlite3.py
+++ b/src/tests/test_sqlite3.py
@@ -1,4 +1,4 @@
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
 
 
 @run_in_pyodide
diff --git a/src/tests/test_typeconversions.py b/src/tests/test_typeconversions.py
index 6067e8a73..6c625cc14 100644
--- a/src/tests/test_typeconversions.py
+++ b/src/tests/test_typeconversions.py
@@ -4,9 +4,8 @@ from typing import Any
 import pytest
 from hypothesis import assume, given, settings, strategies
 from hypothesis.strategies import from_type, text
-
-from conftest import selenium_context_manager
-from pyodide_build.testing import run_in_pyodide
+from pyodide_test_runner import run_in_pyodide
+from pyodide_test_runner.fixture import selenium_context_manager
 
 
 @given(s=text())
diff --git a/tools/node_test_driver.js b/tools/node_test_driver.js
deleted file mode 100644
index 205932da9..000000000
--- a/tools/node_test_driver.js
+++ /dev/null
@@ -1,75 +0,0 @@
-const vm = require("vm");
-const readline = require("readline");
-const path = require("path");
-const util = require("util");
-const node_fetch = require("node-fetch");
-const base64 = require("base-64");
-
-require(path.resolve("./pyodide.js"));
-let base_url = process.argv[2];
-// node requires full paths.
-function fetch(path) {
-    return node_fetch(new URL(path, base_url).toString());
-}
-
-const context = Object.assign({}, globalThis, {
-    path,
-    process,
-    require,
-    fetch,
-    TextDecoder: util.TextDecoder,
-    TextEncoder: util.TextEncoder,
-    URL,
-    atob: base64.decode,
-    btoa: base64.encode,
-});
-vm.createContext(context);
-vm.runInContext("globalThis.self = globalThis;", context);
-
-// Get rid of all colors in output of console.log, they mess us up.
-for (let key of Object.keys(util.inspect.styles)) {
-    util.inspect.styles[key] = undefined;
-}
-
-const rl = readline.createInterface({
-    input: process.stdin,
-    output: process.stdout,
-    terminal: false,
-});
-
-let cur_code = "";
-let cur_uuid;
-rl.on("line", async function (line) {
-    if (!cur_uuid) {
-        cur_uuid = line;
-        return;
-    }
-    if (line !== cur_uuid) {
-        cur_code += line + "\n";
-    } else {
-        evalCode(cur_uuid, cur_code, context);
-        cur_code = "";
-        cur_uuid = undefined;
-    }
-});
-
-async function evalCode(uuid, code, eval_context) {
-    let p = new Promise((resolve, reject) => {
-        eval_context.___outer_resolve = resolve;
-        eval_context.___outer_reject = reject;
-    });
-    let wrapped_code = `
-      (async function(){
-          ${code}
-      })().then(___outer_resolve).catch(___outer_reject);
-      `;
-    let delim = uuid + ":UUID";
-    console.log(delim);
-    try {
-        vm.runInContext(wrapped_code, eval_context);
-        let result = JSON.stringify(await p);
-        console.log(`${delim}\n0\n${result}\n${delim}`);
-    } catch (e) {
-        console.log(`${delim}\n1\n${e.stack}\n${delim}`);
-    }
-}
diff --git a/tools/testsetup.js b/tools/testsetup.js
deleted file mode 100644
index eca7b4c6a..000000000
--- a/tools/testsetup.js
+++ /dev/null
@@ -1,76 +0,0 @@
-Error.stackTraceLimit = Infinity;
-
-// Fix globalThis is messed up in firefox see facebook/react#16606.
-// Replace it with window.
-globalThis.globalThis = globalThis.window || globalThis;
-
-globalThis.sleep = function (s) {
-    return new Promise((resolve) => setTimeout(resolve, s));
-};
-
-globalThis.assert = function (cb, message = "") {
-    if (message !== "") {
-        message = "\n" + message;
-    }
-    if (cb() !== true) {
-        throw new Error(
-            `Assertion failed: ${cb.toString().slice(6)}${message}`
-        );
-    }
-};
-
-globalThis.assertAsync = async function (cb, message = "") {
-    if (message !== "") {
-        message = "\n" + message;
-    }
-    if ((await cb()) !== true) {
-        throw new Error(
-            `Assertion failed: ${cb.toString().slice(12)}${message}`
-        );
-    }
-};
-
-function checkError(err, errname, pattern, pat_str, thiscallstr) {
-    if (typeof pattern === "string") {
-        pattern = new RegExp(pattern);
-    }
-    if (!err) {
-        throw new Error(`${thiscallstr} failed, no error thrown`);
-    }
-    if (err.constructor.name !== errname) {
-        throw new Error(
-            `${thiscallstr} failed, expected error ` +
-                `of type '${errname}' got type '${err.constructor.name}'`
-        );
-    }
-    if (!pattern.test(err.message)) {
-        throw new Error(
-            `${thiscallstr} failed, expected error ` +
-                `message to match pattern ${pat_str} got:\n${err.message}`
-        );
-    }
-}
-
-globalThis.assertThrows = function (cb, errname, pattern) {
-    let pat_str = typeof pattern === "string" ? `"${pattern}"` : `${pattern}`;
-    let thiscallstr = `assertThrows(${cb.toString()}, "${errname}", ${pat_str})`;
-    let err = undefined;
-    try {
-        cb();
-    } catch (e) {
-        err = e;
-    }
-    checkError(err, errname, pattern, pat_str, thiscallstr);
-};
-
-globalThis.assertThrowsAsync = async function (cb, errname, pattern) {
-    let pat_str = typeof pattern === "string" ? `"${pattern}"` : `${pattern}`;
-    let thiscallstr = `assertThrowsAsync(${cb.toString()}, "${errname}", ${pat_str})`;
-    let err = undefined;
-    try {
-        await cb();
-    } catch (e) {
-        err = e;
-    }
-    checkError(err, errname, pattern, pat_str, thiscallstr);
-};