How to use test_should_authenticate_with_empty_password method in Playwright Python

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For the 1st form:

def get_playwright():
    with sync_playwright() as playwright:
        yield playwright

print(get_playwright())  # <generator object get_playwright at 0x108aac580>

That is expected because get_playwright is a generator, which returns a generator iterator, which you have to call next(...) on to get each yielded value from the iterator.

Consider a simpler, non-playwright example:

In [14]: def generate_nums():
    ...:     for num in range(10):
    ...:         yield num
    ...: 

In [15]: nums = generate_nums()

In [16]: nums
Out[16]: <generator object generate_nums at 0x11115e6d0>

In [17]: next(nums)
Out[17]: 0

In [18]: next(nums)
Out[18]: 1

In [19]: next(nums)
Out[19]: 2

For more examples, see Understanding generators in Python.

Since your get_playwright returns an iterator, you need to call next() once to get the actual object:

from playwright.sync_api import sync_playwright


def get_playwright():
    with sync_playwright() as playwright:
        yield playwright

playwright_generator = get_playwright()
print(playwright_generator)  # <generator object get_playwright at 0x104031580>

playwright = next(playwright_generator)
print(playwright)  # <playwright._impl._playwright.Playwright object at 0x1041aabb0>

For the 2nd form:

@pytest.fixture()
def get_playwright():
    with sync_playwright() as playwright:
        yield playwright

def test(get_playwright):
    print(get_playwright)

It should be the same case, but it's just that pytest automatically calls next() on the fixture value if it's a generator. I could not find documentation for this behavior from the pytest docs, but it was mentioned by one of the pytest author's/maintainer's in a different answer:

Here's roughly the execution here

• pytest notices your fixture is used for the test function
• pytest calls the fixture function
  • since it is a generator, it returns immediately without executing code
• pytest notices it is a generator, calls next(...) on it
  • this causes the code to execute until the yield and then "pausing". you can think of it kind of as a co-routine ...
• pytest then executes your test function

...which is probably why the value passed to your test function is already the next-ed value, the playwright object.

Functions assigned to events (in any module) can't return value and you may need to use global variable for this. But lambda can't use global and can't assign value to variable so it needs normal function

url = ""

def on_response(response):
    global url  # inform functio to use external variable (instead of local variable) when you use `=` to assign value
    
    if ".m3u8" in response.url:
        url = response.url

page.on("response", on_response) 

Absent seeing the actual site, a traditional selection and get_attribute should be sufficient:

from playwright.sync_api import sync_playwright

with sync_playwright() as p:
    browser = p.chromium.launch(headless=True)
    page = browser.new_page()
    page.set_content("""
    <iframe title="IFRAME_NAME" src="https://www.data_I_want_TO_get.com"></iframe>
    """)
    src = page.get_attribute('iframe[title="IFRAME_NAME"]', "src")
    print(src)  # => https://www.data_I_want_TO_get.com
    browser.close()

If the frame isn't immediately visible you can wait for it by replacing the src = line with

src = (
    page.wait_for_selector('iframe[title="IFRAME_NAME"]')
        .get_attribute("src")
)

Playwright handle differently with elements than the older python browsers...

in dropdown you should page.select_option(selector)

that's also why in Playwright you can't click a check box, you should page.check(selector) https://playwright.dev/python/docs/api/class-page#page-select-option

Just use some condition instead of print method, for example you could check if response contains some key in its json:

def run(playwright):
    chromium = playwright.chromium
    browser = chromium.launch()
    page = browser.new_page()
    # Subscribe to "request" and "response" events.
    page.on("request", lambda request: print(">>", request.method, request.url))
    page.on("response", lambda response: print("<<", response.status, response.url))
    page.goto("https://example.com")
    browser.close()

For Example:

page.on("response", lambda response: response if key in response.body())

There should be waitForResponse for python too, and you could use that.

I just found the answer:

I need to set also the following and it works: browser.new_context(no_viewport=True)

as mentioned in https://github.com/microsoft/playwright-python/issues/480

Jupyter notebook uses asyncio event loop, so you should use async api.

from playwright.async_api import async_playwright

playwright = await async_playwright().start()
browser = await playwright.chromium.launch(headless = False)
page = await browser.new_page()

await page.goto("http://whatsmyuseragent.org/")

# await page.screenshot(path="example.png")
# await browser.close()
# await playwright.stop()

If you use sync API, it will throw an Error like this:

from playwright.sync_api import sync_playwright
playwright = sync_playwright().start()

'''
Error: It looks like you are using Playwright Sync API inside the asyncio loop.
Please use the Async API instead.
'''

as mentioned in https://github.com/microsoft/playwright-python/issues/480

Jupyter notebook uses asyncio event loop, so you should use async api.

from playwright.async_api import async_playwright

playwright = await async_playwright().start()
browser = await playwright.chromium.launch(headless = False)
page = await browser.new_page()

await page.goto("http://whatsmyuseragent.org/")

# await page.screenshot(path="example.png")
# await browser.close()
# await playwright.stop()

If you use sync API, it will throw an Error like this:

from playwright.sync_api import sync_playwright
playwright = sync_playwright().start()

'''
Error: It looks like you are using Playwright Sync API inside the asyncio loop.
Please use the Async API instead.
'''