Give Screen.open enough budget to retry a slow page load

nicegui/testing/screen.py

@@ -29,6 +29,7 @@
 class Screen:
     PORT = 3392
     IMPLICIT_WAIT = 4
+    PAGE_LOAD_TIMEOUT = 4
     SCREENSHOT_DIR = Path('screenshots')
     CATCH_JS_ERRORS = True
 
@@ -75,10 +76,13 @@ def stop_server(self) -> None:
         if core.loop:
             assert core.loop.is_closed()
 
-    def open(self, path: str, timeout: float = 3.0) -> None:
+    def open(self, path: str, timeout: float = 3 * PAGE_LOAD_TIMEOUT) -> None:
         """Try to open the page until the server is ready or we time out.
 
         If the server is not yet running, start it.
+
+        The timeout must stay above ``PAGE_LOAD_TIMEOUT``: a single slow page load already
+        consumes that much, so a smaller budget would leave no room to retry.
         """
         if self.server_thread is None:
             self.start_server()

nicegui/testing/screen_plugin.py

@@ -92,7 +92,7 @@ def nicegui_driver(nicegui_chrome_options: webdriver.ChromeOptions) -> Generator
     else:  # no break
         raise RuntimeError('Could not start Chrome WebDriver.')
     driver_.implicitly_wait(Screen.IMPLICIT_WAIT)
-    driver_.set_page_load_timeout(4)
+    driver_.set_page_load_timeout(Screen.PAGE_LOAD_TIMEOUT)
     yield driver_
     driver_.quit()