Dialogs

Introduction

CSTesting can interact with JavaScript dialogs: alert, confirm, and prompt, as well as the beforeunload confirmation when closing the page. You set how the next dialog will be handled before the action that triggers it (e.g. before click()). If you do not set a response, the action that opens the dialog can block until the dialog is handled (behavior depends on the browser/backend).

alert(), confirm(), prompt() dialogs

In C:\CSTesting-Python, register a dialog handler on BrowserApi with browser.set_dialog_handler(fn). The handler receives {"type": "alert"|"confirm"|"prompt"|..., "message": "..."} and returns a dict:

• Accept: {"accept": True} — optional "prompt_text" for prompts.
• Dismiss: {"accept": False} — confirm/prompt Cancel.

Set the handler before the action that opens the dialog. Call browser.set_dialog_handler(None) to clear.

Example: accept alert

def on_dialog(evt):
    return {"accept": True}

browser.set_dialog_handler(on_dialog)
await browser.locator("#btnAlert").click()  # alert("Hello")
browser.set_dialog_handler(None)

Example: dismiss confirm

browser.set_dialog_handler(lambda e: {"accept": False})
await browser.locator("#btnConfirm").click()

Example: prompt with text

browser.set_dialog_handler(lambda e: {"accept": True, "prompt_text": "my input"})
await browser.locator("#btnPrompt").click()

beforeunload dialog

Playwright may show a beforeunload prompt when leaving the page. Use the same set_dialog_handler pattern before await browser.close() or navigation if your app uses beforeunload.

browser.set_dialog_handler(lambda e: {"accept": True})
await browser.close()
browser.set_dialog_handler(None)

Print dialogs

CSTesting does not provide a dedicated API for print dialogs (window.print()). The native print dialog is controlled by the OS/browser and is not a JavaScript alert/confirm/prompt dialog.

To test that a print dialog would be triggered, you can:

• Stub window.print in the page (e.g. via browser.evaluate(...)) and assert that it was called, or
• Rely on your app's own logic and assert on the state of the page before/after the "Print" action.

Example of stubbing and asserting that print was requested:

from cstesting import expect

await browser.goto("https://example.com/page-with-print")
await browser.evaluate(
    "window.printRequested = false; window.print = function() { window.printRequested = true; };"
)
await browser.locator("//button[contains(.,'Print')]").first().click()
requested = await browser.evaluate("window.printRequested")
expect(requested).to_be_truthy()

(Adjust the selector to match your page; use XPath if needed, e.g. //button[contains(.,'Print')].)

Summary

Dialog type	CSTesting API	Notes
alert / confirm / prompt	browser.set_dialog_handler(fn) then action	Return {"accept": True/False, "prompt_text": "..."}.
beforeunload	Handler before close() / navigate	Same handler API.
Print	No built-in API	Stub window.print and assert it was called if needed.