[py]: reuse driver in case of bidi tests (#16597)

Author: navin772

py/conftest.py

@@ -343,12 +343,28 @@ def driver(request):
 
         request.addfinalizer(selenium_driver.stop_driver)
 
-    # Close the browser after BiDi tests. Those make event subscriptions
-    # and doesn't seems to be stable enough, causing the flakiness of the
-    # subsequent tests.
-    # Remove this when BiDi implementation and API is stable.
+    # For BiDi tests, only restart driver when explicitly marked as needing fresh driver.
+    # Tests marked with @pytest.mark.needs_fresh_driver get full driver restart for test isolation.
+    # Cleanup after every test is recommended.
     if selenium_driver is not None and selenium_driver.bidi:
-        request.addfinalizer(selenium_driver.stop_driver)
+        if request.node.get_closest_marker("needs_fresh_driver"):
+            request.addfinalizer(selenium_driver.stop_driver)
+        else:
+
+            def ensure_valid_window():
+                try:
+                    driver = selenium_driver._driver
+                    if driver:
+                        try:
+                            # Check if current window is still valid
+                            driver.current_window_handle
+                        except Exception:
+                            # restart driver
+                            selenium_driver.stop_driver()
+                except Exception:
+                    pass
+
+            request.addfinalizer(ensure_valid_window)
 
     yield selenium_driver.driver
 

py/pyproject.toml

@@ -86,7 +86,8 @@ markers = [
     "xfail_safari: Tests expected to fail in Safari",
     "xfail_webkitgtk: Tests expected to fail in WebKitGTK",
     "xfail_wpewebkit: Tests expected to fail in WPEWebKit",
-    "no_driver_after_test: If there are no drivers after the test it will create a new one."
+    "no_driver_after_test: If there are no drivers after the test it will create a new one.",
+    "needs_fresh_driver: Mark tests that may need a fresh driver instance for proper isolation."
 ]
 python_files = ["test_*.py", "*_test.py", "*_tests.py"]
 testpaths = ["test"]

py/test/selenium/webdriver/common/bidi_browsing_context_tests.py

@@ -721,6 +721,7 @@ def on_user_prompt_opened(info):
     create_alert_page(driver, pages)
     driver.find_element(By.ID, "alert").click()
     WebDriverWait(driver, 5).until(EC.alert_is_present())
+    WebDriverWait(driver, 5).until(lambda d: len(events_received) > 0)
 
     assert len(events_received) == 1
     assert events_received[0].type == "alert"

py/test/selenium/webdriver/common/bidi_network_tests.py

@@ -33,6 +33,9 @@ def test_add_intercept(driver, pages):
     result = driver.network._add_intercept()
     assert result is not None, "Intercept not added"
 
+    # Clean up
+    driver.network._remove_intercept(result["intercept"])
+
 
 def test_remove_intercept(driver):
     result = driver.network._add_intercept()
@@ -88,6 +91,8 @@ def callback(request: Request):
     assert driver.find_element(By.NAME, "login").is_displayed(), "Request not continued"
     assert len(exceptions) == 0, "Exception raised when continuing request in handler callback"
 
+    driver.network.remove_request_handler("before_request", callback_id)
+
 
 def test_continue_with_auth(driver):
     callback_id = driver.network.add_auth_handler("postman", "password")
@@ -97,6 +102,8 @@ def test_continue_with_auth(driver):
     )
     assert "authenticated" in driver.page_source, "Authorization failed"
 
+    driver.network.remove_auth_handler(callback_id)
+
 
 def test_remove_auth_handler(driver):
     callback_id = driver.network.add_auth_handler("user", "passwd")
@@ -124,6 +131,8 @@ def callback(request: Request):
     pages.load("formPage.html")
     assert len(exceptions) == 0, "Exception raised in handler callback"
 
+    driver.network.remove_request_handler("before_request", callback_id)
+
 
 @pytest.mark.xfail_chrome(reason="Data URLs in Network requests are not implemented in Chrome yet")
 @pytest.mark.xfail_edge(reason="Data URLs in Network requests are not implemented in Edge yet")
@@ -140,10 +149,12 @@ def callback(request: Request):
         except WebDriverException as e:
             exceptions.append(e)
 
-    driver.network.add_request_handler("before_request", callback)
+    callback_id = driver.network.add_request_handler("before_request", callback)
     url = pages.url("data_url.html")
     driver.browsing_context.navigate(context=driver.current_window_handle, url=url, wait=ReadinessState.COMPLETE)
     time.sleep(1)  # give callback time to complete
     assert driver.find_element(By.ID, "data-url-image").is_displayed()
     assert len(data_requests) > 0, "BiDi event not captured"
     assert len(exceptions) == 0, "Exception raised when continuing request in handler callback"
+
+    driver.network.remove_request_handler("before_request", callback_id)