Tests fail from time to time `assert "return 'change'" in 'return "init"'`

[agoscinski]

I am not sure what the reason is, a sleep time before the test also seems not to fix it

=================================== FAILURES ===================================
__________________________ test_scwidgets_code_input ___________________________

selenium_driver = <function selenium_driver.<locals>._selenium_driver at 0x7f7ce36b4f40>

    def test_scwidgets_code_input(selenium_driver):
        """
        Tests the widget of the module code
    
        :param selenium_driver: see conftest.py
        """
        driver = selenium_driver("tests/notebooks/widget_scwidgets_code_input.ipynb")
    
        nb_cells = NotebookCellList(driver)
        # Test 1:
        # -------
    
        # Tests if change in function_body changed the widget view
        time.sleep(2)
        code_input_lines = nb_cells[2].find_elements(By.CLASS_NAME, CODE_MIRROR_CLASS_NAME)
>       assert "return 'change'" in code_input_lines[-1].text
E       assert "return 'change'" in 'return "init"'
E        +  where 'return "init"' = <selenium.webdriver.remote.webelement.WebElement (session="8b2859cb-e3e0-458a-8102-9bebb2914a72", element="6c09559c-7e6b-4822-a90c-6c055ce68446")>.text

tests/test_widgets.py:267: AssertionError