Appium hangs when finder is not working.

[hex0cter]

During the tests I have found the Appium request stalls when a command is not working. For instance, I would like to add the following code in https://github.com/truongsinh/appium-flutter-driver/blob/master/example/python/example.py.

counter_finder = FlutterFinder().by_semantics_label("counter_semantic")
counter_element = FlutterElement(driver, counter_finder)
print(counter_element.text)

However the code stops at the last line. Here is the log of Appium:

2021-03-20 13:56:43:570 - [HTTP]
2021-03-20 13:56:43:571 - [HTTP] --> GET /wd/hub/session/971ef296-5825-44d1-a6d7-97e9f1c397f2/element/eyJmaW5kZXJUeXBlIjogIkJ5U2VtYW50aWNzTGFiZWwiLCAiaXNSZWdFeHAiOiBmYWxzZSwgImxhYmVsIjogImNvdW50ZXJfc2VtYW50aWMifQ==/text
2021-03-20 13:56:43:572 - [HTTP] {}
2021-03-20 13:56:43:572 - [debug] [MJSONWP (971ef296)] Calling AppiumDriver.getText() with args: ["eyJmaW5kZXJUeXBlIjogIkJ5U2VtYW50aWNzTGFiZWwiLCAiaXNSZWdFeHAiOiBmYWxzZSwgImxhYmVsIjogImNvdW50ZXJfc2VtYW50aWMifQ==","971ef296-5825-44d1-a6d7-97e9f1c397f2"]
2021-03-20 13:56:43:572 - [debug] [FlutterDriver] Executing Flutter driver command 'getText'

then nothing happens forever.

So I have two questions here:

1. Did I do anything wrong with the code. I got the label counter_semantic from https://github.com/truongsinh/appium-flutter-driver/blob/master/example/flutter_app_under_test/lib/main.dart#L43 but let me know if I did something stupid.
2. Even if something is wrong with the test code, why is the code hanging instead of returning an error?

Any help will be appreciated.

[karlisV]

Hi, @hex0cter! Don't know if it's still an issue, but what we did to work around this issue was to call flutter:waitFor and pass in the finder as a parameter, before we initialized the Flutter element itself. Because it raises an exception if the finder is not found in the given time it worked quite well in our case. Not a python user so can't give you the exact example, but in ruby, we did something similar to this: defined a method that checks if a finder exists

  def displayed?(finder, wait)
    @driver.driver.execute_script('flutter:waitFor', finder, wait)
    true
  rescue Selenium::WebDriver::Error::UnknownError
    false
  end

Then created a method that returns the element or raises an exception, similar to this:

  def element(finder, wait)
    raise Selenium::WebDriver::Error::NoSuchElementError, 'Element not found' unless displayed?(finder, wait)

    ::Appium::Flutter::Element.new(@driver.driver, finder: finder)
  end

Although the example is in ruby, I think the general approach can be used in python as well.