ENH Add fixtures for JSPI

These let us enable JSPI only for specific tests rather than globally, and allows
marking tests as jspi-only or to be run with both jspi and no jspi.

pytest_pyodide/fixture.py

@@ -77,6 +77,7 @@ def selenium_common(
     load_pyodide=True,
     script_type="classic",
     browsers=None,
+    jspi=False,
 ):
     """Returns an initialized selenium object.
 
@@ -110,6 +111,7 @@ def selenium_common(
         browsers=browsers,
         script_type=script_type,
         dist_dir=dist_dir,
+        jspi=jspi,
     )
     try:
         yield runner
@@ -239,11 +241,37 @@ def selenium_context_manager(selenium_module_scope):
 
 @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.node)
-        ):
-            yield selenium
+    with selenium_context_manager(
+        selenium_module_scope
+    ) as selenium, set_webdriver_script_timeout(
+        selenium, script_timeout=parse_driver_timeout(request.node)
+    ):
+        yield selenium
+
+
+@pytest.fixture
+def selenium_jspi(request, runtime, web_server_main, playwright_browsers):
+    if runtime in ["firefox", "safari"]:
+        pytest.skip(f"jspi not supported in {runtime}")
+    with selenium_common(
+        request, runtime, web_server_main, browsers=playwright_browsers, jspi=True
+    ) as selenium, set_webdriver_script_timeout(
+        selenium, script_timeout=parse_driver_timeout(request.node)
+    ):
+        yield selenium
+
+
+@pytest.fixture(params=[False, True])
+def selenium_also_with_jspi(request, runtime, web_server_main, playwright_browsers):
+    jspi = request.param
+    if jspi and runtime in ["firefox", "safari"]:
+        pytest.skip(f"jspi not supported in {runtime}")
+    with selenium_common(
+        request, runtime, web_server_main, browsers=playwright_browsers, jspi=jspi
+    ) as selenium, set_webdriver_script_timeout(
+        selenium, script_timeout=parse_driver_timeout(request.node)
+    ):
+        yield selenium
 
 
 @pytest.fixture(scope="function")

pytest_pyodide/runner.py

@@ -116,6 +116,7 @@ def __init__(
         load_pyodide=True,
         script_type="classic",
         dist_dir=None,
+        jspi=False,
         *args,
         **kwargs,
     ):
@@ -125,7 +126,7 @@ def __init__(
         self.server_log = server_log
         self.script_type = script_type
         self.dist_dir = dist_dir
-        self.driver = self.get_driver()
+        self.driver = self.get_driver(jspi)
         self.set_script_timeout(self.script_timeout)
         self.prepare_driver()
         self.javascript_setup()
@@ -135,7 +136,7 @@ def __init__(
             self.save_state()
             self.restore_state()
 
-    def get_driver(self):
+    def get_driver(self, jspi=False):
         raise NotImplementedError()
 
     def goto(self, page):
@@ -378,7 +379,9 @@ def __init__(self, browsers, *args, **kwargs):
     def goto(self, page):
         self.driver.goto(page)
 
-    def get_driver(self):
+    def get_driver(self, jspi=False):
+        if jspi:
+            raise NotImplementedError("JSPI not supported with playwright")
         return self.browsers[self.browser].new_page()
 
     def set_script_timeout(self, timeout):
@@ -417,7 +420,9 @@ def run_js_inner(self, code, check_code):
 class SeleniumFirefoxRunner(_SeleniumBaseRunner):
     browser = "firefox"
 
-    def get_driver(self):
+    def get_driver(self, jspi=False):
+        if jspi:
+            raise NotImplementedError("JSPI not supported in Firefox")
         from selenium.webdriver import Firefox
         from selenium.webdriver.firefox.options import Options
         from selenium.webdriver.firefox.service import Service
@@ -433,13 +438,16 @@ def get_driver(self):
 class SeleniumChromeRunner(_SeleniumBaseRunner):
     browser = "chrome"
 
-    def get_driver(self):
+    def get_driver(self, jspi=False):
         from selenium.webdriver import Chrome
         from selenium.webdriver.chrome.options import Options
 
         options = Options()
         options.add_argument("--headless")
         options.add_argument("--no-sandbox")
+        if jspi:
+            options.add_argument("--enable-features=WebAssemblyExperimentalJSPI")
+            options.add_argument("--enable-experimental-webassembly-features")
         for flag in CHROME_FLAGS:
             options.add_argument(flag)
         return Chrome(options=options)
@@ -452,7 +460,9 @@ class SeleniumSafariRunner(_SeleniumBaseRunner):
     browser = "safari"
     script_timeout = 30
 
-    def get_driver(self):
+    def get_driver(self, jspi=False):
+        if jspi:
+            raise NotImplementedError("JSPI not supported in Firefox")
         from selenium.webdriver import Safari
         from selenium.webdriver.safari.options import Options
 
@@ -475,7 +485,7 @@ class PlaywrightFirefoxRunner(_PlaywrightBaseRunner):
 class NodeRunner(_BrowserBaseRunner):
     browser = "node"
 
-    def init_node(self):
+    def init_node(self, jspi=False):
         curdir = Path(__file__).parent
         self.p = pexpect.spawn("/bin/bash", timeout=60)
         self.p.setecho(False)
@@ -488,6 +498,8 @@ def init_node(self):
         extra_args = NODE_FLAGS[:]
         # Node v14 require the --experimental-wasm-bigint which
         # produces errors on later versions
+        if jspi:
+            extra_args.append("--experimental-wasm-stack-switching")
         if node_version.startswith("v14"):
             extra_args.append("--experimental-wasm-bigint")
 
@@ -500,9 +512,9 @@ def init_node(self):
         except (pexpect.exceptions.EOF, pexpect.exceptions.TIMEOUT):
             raise JavascriptException("", self.p.before.decode()) from None
 
-    def get_driver(self):
+    def get_driver(self, jspi=False):
         self._logs = []
-        self.init_node()
+        self.init_node(jspi)
 
         class NodeDriver:
             def __getattr__(self, x):

tests/test_fixture.py

@@ -24,3 +24,10 @@ def test_playwright_browsers(playwright_browsers, request):
     runtimes = pytest.pyodide_runtimes
 
     assert set(playwright_browsers.keys()) == set(runtimes)
+
+
+@run_in_pyodide
+def test_jspi(selenium_jspi):
+    from js import WebAssembly
+
+    assert hasattr(WebAssembly, "Suspender")