Set the runtime shared variable zeuz_browser_driver to playwright to run existing selenium action rows with Playwright, or use playwright action directly. Without that value, Selenium routing is unchanged. open electron app and accessibility test remain Selenium-owned.
The Playwright declaration set contains exactly these 55 Selenium-compatible actions:
click, click and download, right click, double click, hover, keystroke keys, keystroke chars, text, validate full text, validate partial text, deselect all, select by visible text, deselect by visible text, select by value, deselect by value, select by index, deselect by index, open browser, open electron app, go to link, go to link v2, tear down browser, switch browser, get current url, navigate, handle alert, teardown, open new tab, close tab, upload file, drag and drop, get element info, scroll, scroll to element, scroll element to top, scroll to top, switch window, switch window or frame, switch window/tab, switch iframe, save attribute, save attribute values in list, extract table data, save web elements in list, take screenshot web, execute javascript, check uncheck all, check uncheck, multiple check uncheck, slider bar, resize window, change attribute value, capture network log, if element exists, and copy image into browser.
Action values and supplemental rows retain their Selenium meanings. Common examples are driver id, resolution, wait for element, wait time to page load, offset, use js, ignore case, variable, fullscreen, tab title, tab index, row, column, pixels, wait for download, and folder path. Files, downloads, screenshots, saved elements, extracted values, URLs, dialog text, and network logs use the existing shared-variable contracts.
A normal click that times out because a visible, enabled target is outside the viewport requests centered scrolling inside the target's frame, then explicitly scrolls the main page using the target's page-relative bounds and retries the normal click once. Like Selenium, persistent pointer interception falls back to a JavaScript click. Both recoveries log a warning and exclude offset clicks and unrelated timeout causes; an element that remains outside the viewport still fails.
An explicit use js click dispatches mousedown, mouseup, and click, matching
the Selenium action. Normal text entry uses select-all/delete to clear, types the
requested text, and attempts a final click on the same element, as Selenium does.
Without an action-level typing delay, native key-down/key-up events are queued
together, like ChromeDriver's send_keys, instead of awaiting each event before
sending the next. Keyboard handlers, including cancellation, still run normally;
non-US-layout characters retain Playwright's native text insertion behavior.
keystroke chars uses the same event delivery, including when no element is given.
An explicit nonzero text-action delay retains ordinary sequential typing. No deployment
delay variables or screenshots are required by this implementation.
Batching uses Playwright's internal sync/async bridge; run the compatibility tests
when upgrading Playwright.
Locators accept exact attributes and text (id, name, text), partial matches (*id, *text), case-insensitive partial matches (**id, **text), tag, raw css/css selector, raw xpath, and positive or negative index rows. The relationship subfields are parent parameter, child parameter, sibling parameter, preceding parameter, and following parameter, including their numbered forms.
wait, allow hidden, allow disable, and text filter are optional rows. save parameter stores a locator; get parameter retrieves one. Locator roots may be saved elements, frames, nested elements, and open shadow roots using numbered sr ... parameter rows. Closed shadow roots are not accessible.
Set the runtime shared variable zeuz_playwright_diagnostics to true for all
test cases, or a comma-separated list such as TEST-0390,TEST-0391,TEST-0392.
It is disabled by default. Use the same deployment mechanism as
zeuz_browser_driver.
The console and action logs receive JSON records prefixed with PW_DIAGNOSTIC
around clicks, double-clicks, text entry, attribute readbacks, and screenshots. Records include
case/step/action IDs, target attributes and bounds (main_rect uses main-page viewport coordinates), elements at the target's
center in its frame and the main page, active/hovered elements, visible overlays,
and the latest 30 pointer, focus, input, and change events per frame. Input values
and key characters are omitted; non-password input lengths are recorded.
Click events include their click count (detail). Selection attributes and up to
30 checkbox, switch, or busy controls per frame help diagnose selection changes.
These records supplement the existing error tracebacks; they do not create
Playwright trace.zip files. Send the complete console log after the rerun.
Collection errors do not change action results. Enabled diagnostics add browser
round trips and logging, so leave them disabled for timing comparisons.
| ZeuZ browser | Playwright engine |
|---|---|
| Chrome / ChromeHeadless | Chromium, channel="chrome" |
| Microsoft Edge Chromium / EdgeChromiumHeadless | Chromium, channel="msedge" |
| FireFox / FirefoxHeadless | Bundled Firefox |
| Safari | Bundled WebKit |
Launch rows support raw browser arguments, page-load strategy, resolution/viewport, proxy, locale, user agent, permissions, HTTPS error handling, Firefox preferences, download behavior, and Chromium debugger address CDP attachment. Opera fails explicitly.
The viewport uses runtime window_size_x and window_size_y when both are set, otherwise it defaults to 1920×1080 to match Selenium's maximized/headless node behavior. An explicit resolution row takes precedence.
Unknown Selenium capabilities, Chrome version pinning, experimental options, and extension sideloading on branded Chrome/Edge are logged and ignored because they do not have a safe equivalent. The installer exposes bundled Firefox and WebKit; branded Chrome and Edge continue through their existing installers.
Playwright-launched Chrome and Edge expose a Selenium CDP bridge as the existing selenium_driver shared/global variable. Existing execute python code rows such as selenium_driver.execute_script(...) therefore control the same browser without test-data changes. The bridge is selected with its Playwright driver ID and detached during Playwright teardown; it does not own or close the browser.
This bridge is unavailable for Firefox and WebKit because Selenium's debugger attachment is Chromium-only. Commands that ChromeDriver itself does not support for debugger-attached sessions remain unsupported.
Known limitation: long-running Firefox or WebKit (Safari) sessions that use
capture network log can retain network objects between tests, particularly with
zeuz_auto_teardown=False and include response body=true. The Chromium capture
fix does not eliminate this risk in Firefox/WebKit.
Watch for Python/Playwright-driver memory growing across tests, eventual
out-of-memory (OOM) kills, or a run abruptly stopping without a Python traceback.
On Linux, an OOM-related systemd scope shutdown can also remove the tmux pane or
session even though the VM never rebooted. These symptoms alone do not prove
network retention; inspect kernel logs for Out of memory, Killed process, and
the system journal for oom-kill. The process chosen for the kill is not
necessarily the only large memory consumer.
Playwright's event-based network API creates live Request/Response objects
that can remain referenced inside its connection/dispatcher registries. Reading
response bodies can additionally cache data in the Playwright driver. Clearing
ZeuZ's state["network"], deleting the saved output variable, or calling Python
gc.collect() does not release objects still referenced by Playwright. Removing
listeners stops future reporting but does not dispose of previously reported
objects. Reloading the page is not equivalent to closing it.
The original retention was reproduced on Chromium with Playwright 1.62.0; the Firefox/WebKit fallback retains the same kind of event-based capture. A Firefox/WebKit OOM was not separately reproduced during that investigation. Recheck retention behavior when changing Playwright versions. See Playwright's request-history lifetime documentation.
- Chrome/Edge/Chromium: capture uses a temporary CDP session through
Playwright's
context.new_cdp_session(). It collects plain network details and retrieves bodies without creating Playwright request/response history. Stop disables tracking and detaches the session. This does not use Selenium to capture traffic and does not close the browser or clear login state. - Firefox/WebKit: CDP is unavailable. Capture therefore uses native
Playwright response events, subscribed only between start and stop. Test-end
cleanup also removes unfinished captures, including after failures, regardless
of
zeuz_auto_teardown. This limits capture lifetime, but does not guarantee release of the internal request/response history. - If session reuse is unnecessary, use
zeuz_auto_teardown=on. Otherwise, close and recreate the page/context or explicitly tear down the browser at suitable test boundaries, accounting for lost page state and any required login. Avoid capturing traffic or response bodies that the tests do not need. - More RAM/swap provides headroom, not a retention fix. Do not substitute
page.requests()for complete capture without changing the action contract: its bounded recent-request history can omit earlier requests from a test.
In Playwright/BuiltInFunctions.py,
start with _capture_network_page (Firefox/WebKit fallback),
_capture_network_target (Chromium CDP), capture_network_log, and
_stop_network_capture. cleanup_network_captures is called on the action worker
from the run_test_case finalizer in MainDriverApi.py.
The regression test
test_cdp_capture_reuses_browser_without_retaining_network_objects in
test_playwright_compat.py checks repeated
Chromium captures, iframe traffic, retained object counts, and preserved session
state. It is not a Firefox/WebKit memory regression test. For those engines,
compare repeated captures on one long-lived page with page/context teardown;
check object retention as well as RSS, since freeing objects need not immediately
return allocated memory to the OS.