25 classic selenium automated interview questions, collect them quickly

（1）selenium How it works ？

       ① The script to start driver

       ② driver To drive the browser as a remote server

       ③ Execute the script to send the request

       ④ The server parses the request and takes corresponding actions , And return it to the client ( Script )

（2）selenium The automation page element could not find the reason for the exception ？

        ① Element positioning error

        ② Page loading time is too slow , The element program to find has been completed , Single page not loaded yet , Page waiting time can be loaded at this time

        ③ It is possible that the element is contained in iframe perhaps frame Inside , Need to switch .

（3） How to locate elements with dynamic attributes ？

        Property dynamic change refers to the element There is no fixed attribute value , Can only be located by relative position .

        The first method ： use findelements Traverse

        The second method ： adopt xpath The shaft     parent   /   following-sibling   /   precent-sibling

（4） How to locate dynamically loaded elements on a page ？

         Trigger dynamic events , then findelement; If it's a dynamic menu , Need level by level find.

（5）selenium call js(execute_script), What are the scenes ？

        ① Yes input Perform input

        ② Operations on rich text boxes

        ③ Scroll to the specified position to operate

（6）selenium How to deal with it web Popup ？js Popup ？

        Need to use driver.switch_to.alert()

（7）selenium Can handle window Pop up ？

       selenium It cannot be handled by itself windows The popup window , But with the help of AutoIT Gadgets to complete the right windows Pop up window operation . such as Upload and download attachments, etc

（8） How to highlight an element after positioning it ( For the purpose of debugging )？

        Use javascript Elemental border Or change the background color to yellow or other colors

（9）selenium Support for automated testing of desktop applications ？

         I won't support it .selenium The scope element is determined according to the attributes of the web page element

（10）selenium Is there a read excel Document library ？

         No, , Third party tools are needed . for example Apache PIO plug-in unit

（11）selenium Can I send mouse wheel actions to the page ？

        You can't .

（12） How to be in webdriver Calling application ？

       driver.get('url')  perhaps driver.navigate().to('url')

（13）selenium Common exceptions in ？

       NoSuchElementException    Page element not found exception

       ElementNoInteractac tableException

（14）selenium Why not recommend xpath location ？

       selenium Use xpath When positioning, it uses the way of traversing the page , Poor performance index . in addition xpath Positioning has the ability to locate through an absolute path , Sometimes inaccurate ;

        While using css Selector positioning is relatively simple , Run faster , It is usually used in scenarios with strict performance requirements .

（15） How to determine whether an element on a page exists ？

        Law 1： use try...except   Add... To the code block

        Law 2： use elements Define group element methods   Then root the number of elements len()<1   There is returned True,   Returns if it does not exist False

        Law 3： combination WebDriverWait and excepted_conditions conditional ( Strongly recommend )

                According to wait , Every interval 1 Judge once in a second ,30 Second timeout , There is returned True, Returns if it does not exist False

（16） How to locate dynamic elements ？

        There are two cases of dynamic elements ：

              One is attribute dynamics , When positioning , if id Is dynamic , Don't use id location , Use other methods of locating elements

              The other is that this element will be at the top of the page , I'll be down there later , Erratic , It's the same with positioning , Positioning by element attributes ( Elemental tag name The properties do not change , What's moving is class Properties and style attribute )

（17） How to locate the parent element through the child element ？

        Locate the child element through the parent element , Can be found by secondary positioning .

              The first one is ： Locate the parent element through the child element ,selenium Provides parent Method , But you can only locate the parent element , But can't get element attributes , You can't operate .

              The second kind ： adopt xpath The grammatically direct orientation of .  Such as .//*[@name="hello"]/..    Two points represent the parent element .

（18） How to intercept the image of an element , Don't take all the pictures ？

        It is preferred to intercept the current page and save it in a customized way

        Then get the coordinates and size of the element according to the attributes of the element image to be intercepted ele.location    ele.size

        And then separately left = ele.location['x']

                     top = ele.location['y']

                     right = ele.location['x'] + ele.size['width']

                     bottom = ele.location['y'] + ele.size['height']

        Get the coordinate size of the image of the element

        Last , Open the newly saved... Again , adopt image Class crop Method ( This is equivalent to copying a rectangular area of the element ), Then you can save it .

（19） An element is clearly positioned , Click invalid ( No mistake ), How to solve ？

        Use js Click on ,selenium Sometimes clicking on an element will invalidate

       #  js Click on

       js = 'document.getElementById('baidu').click()'

       driver.execute_script(js)

（20） How to improve the stability of scripts ？

        First, as long as the page hasn't changed , It shows that the positioning method is OK .

        To optimize the direction ：① Write your own relative path , multi-purpose id Find... For nodes , Use less right-click copy xpath, That kind of instability .

                         ② The second factor is waiting ,sleep Wait as little as possible ( Affect execution time )

                         ③ Positioning element method repackaging , combination WebDriverWait and excepted_conditions How to judge elements , Encapsulate a set of positioning element methods

（21） Improve selenium How fast the script executes ？

        Reduce unnecessary operations .

        The page is overloaded and does not affect the test , Timeout can be set to interrupt page loading .

        When setting the waiting time , Sure sleep() Fixed time , Interrupting the wait after detecting the occurrence of an element can also increase the speed .

        To configure testNG Implement multithreading , When writing test cases , Be sure to achieve loose coupling , Set up multithreading as far as the server allows , Improve execution speed .

（22）selenium When automating , What problems have you encountered at ordinary times ？ How to solve ？

        Such as dynamic id  、 Yes iframe The situation of 、 No waiting and other factors

（23）selenium Hide element positioning in , How do you do it ？

        Hidden elements can be positioned to , It just doesn't work ( Positioning elements and manipulating elements are two different things , Operation elements refer to click 、clear 、send_keys Wait for these methods ). We can use js To manipulate hidden elements .js and selenium Different , Only the elements on the page ( stay dom Inside ) Can operate normally .

（24） There are several ways to upload pictures ？

       send_keys and AutoIT Tool implementation .

（25） How should the screenshot work ？

       driver.get_screenshot_as_file('C:\test.jpg')