Selenium是一个用于Web应用程序自动化测试工具。Selenium测试直接运行在浏览器中，就像真正的用户在操作一样。
1.目录结构如下：
D:softpython36Libsite-packagesselenium>tree /f 卷 新加卷 的文件夹 PATH 列表 卷序列号为 960E-961E D:. │ __init__.py │ ├─common │ │ exceptions.py │ │ __init__.py │ │ │ └─__pycache__ │ exceptions.cpython-36.pyc │ __init__.cpython-36.pyc │ ├─webdriver │ │ __init__.py │ │ │ ├─android │ │ │ webdriver.py │ │ │ __init__.py │ │ │ │ │ └─__pycache__ │ │ webdriver.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ ├─blackberry │ │ │ webdriver.py │ │ │ __init__.py │ │ │ │ │ └─__pycache__ │ │ webdriver.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ ├─chrome │ │ │ options.py │ │ │ remote_connection.py │ │ │ service.py │ │ │ webdriver.py │ │ │ __init__.py │ │ │ │ │ └─__pycache__ │ │ options.cpython-36.pyc │ │ remote_connection.cpython-36.pyc │ │ service.cpython-36.pyc │ │ webdriver.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ ├─common │ │ │ action_chains.py │ │ │ alert.py │ │ │ by.py │ │ │ desired_capabilities.py │ │ │ keys.py │ │ │ proxy.py │ │ │ service.py │ │ │ touch_actions.py │ │ │ utils.py │ │ │ __init__.py │ │ │ │ │ ├─actions │ │ │ │ action_builder.py │ │ │ │ input_device.py │ │ │ │ interaction.py │ │ │ │ key_actions.py │ │ │ │ key_input.py │ │ │ │ mouse_button.py │ │ │ │ pointer_actions.py │ │ │ │ pointer_input.py │ │ │ │ __init__.py │ │ │ │ │ │ │ └─__pycache__ │ │ │ action_builder.cpython-36.pyc │ │ │ input_device.cpython-36.pyc │ │ │ interaction.cpython-36.pyc │ │ │ key_actions.cpython-36.pyc │ │ │ key_input.cpython-36.pyc │ │ │ mouse_button.cpython-36.pyc │ │ │ pointer_actions.cpython-36.pyc │ │ │ pointer_input.cpython-36.pyc │ │ │ __init__.cpython-36.pyc │ │ │ │ │ ├─html5 │ │ │ │ application_cache.py │ │ │ │ __init__.py │ │ │ │ │ │ │ └─__pycache__ │ │ │ application_cache.cpython-36.pyc │ │ │ __init__.cpython-36.pyc │ │ │ │ │ └─__pycache__ │ │ action_chains.cpython-36.pyc │ │ alert.cpython-36.pyc │ │ by.cpython-36.pyc │ │ desired_capabilities.cpython-36.pyc │ │ keys.cpython-36.pyc │ │ proxy.cpython-36.pyc │ │ service.cpython-36.pyc │ │ touch_actions.cpython-36.pyc │ │ utils.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ ├─edge │ │ │ options.py │ │ │ service.py │ │ │ webdriver.py │ │ │ __init__.py │ │ │ │ │ └─__pycache__ │ │ options.cpython-36.pyc │ │ service.cpython-36.pyc │ │ webdriver.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ ├─firefox │ │ │ extension_connection.py │ │ │ firefox_binary.py │ │ │ firefox_profile.py │ │ │ options.py │ │ │ remote_connection.py │ │ │ service.py │ │ │ webdriver.py │ │ │ webdriver.xpi │ │ │ webdriver_prefs.json │ │ │ webelement.py │ │ │ __init__.py │ │ │ │ │ ├─amd64 │ │ │ x_ignore_nofocus.so │ │ │ │ │ ├─x86 │ │ │ x_ignore_nofocus.so │ │ │ │ │ └─__pycache__ │ │ extension_connection.cpython-36.pyc │ │ firefox_binary.cpython-36.pyc │ │ firefox_profile.cpython-36.pyc │ │ options.cpython-36.pyc │ │ remote_connection.cpython-36.pyc │ │ service.cpython-36.pyc │ │ webdriver.cpython-36.pyc │ │ webelement.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ ├─ie │ │ │ options.py │ │ │ service.py │ │ │ webdriver.py │ │ │ __init__.py │ │ │ │ │ └─__pycache__ │ │ options.cpython-36.pyc │ │ service.cpython-36.pyc │ │ webdriver.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ ├─opera │ │ │ options.py │ │ │ webdriver.py │ │ │ __init__.py │ │ │ │ │ └─__pycache__ │ │ options.cpython-36.pyc │ │ webdriver.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ ├─phantomjs │ │ │ service.py │ │ │ webdriver.py │ │ │ __init__.py │ │ │ │ │ └─__pycache__ │ │ service.cpython-36.pyc │ │ webdriver.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ ├─remote │ │ │ command.py │ │ │ errorhandler.py │ │ │ file_detector.py │ │ │ getAttribute.js │ │ │ isDisplayed.js │ │ │ mobile.py │ │ │ remote_connection.py │ │ │ switch_to.py │ │ │ utils.py │ │ │ webdriver.py │ │ │ webelement.py │ │ │ __init__.py │ │ │ │ │ └─__pycache__ │ │ command.cpython-36.pyc │ │ errorhandler.cpython-36.pyc │ │ file_detector.cpython-36.pyc │ │ mobile.cpython-36.pyc │ │ remote_connection.cpython-36.pyc │ │ switch_to.cpython-36.pyc │ │ utils.cpython-36.pyc │ │ webdriver.cpython-36.pyc │ │ webelement.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ ├─safari │ │ │ permissions.py │ │ │ remote_connection.py │ │ │ service.py │ │ │ webdriver.py │ │ │ __init__.py │ │ │ │ │ └─__pycache__ │ │ permissions.cpython-36.pyc │ │ remote_connection.cpython-36.pyc │ │ service.cpython-36.pyc │ │ webdriver.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ ├─support │ │ │ abstract_event_listener.py │ │ │ color.py │ │ │ events.py │ │ │ event_firing_webdriver.py │ │ │ expected_conditions.py │ │ │ select.py │ │ │ ui.py │ │ │ wait.py │ │ │ __init__.py │ │ │ │ │ └─__pycache__ │ │ abstract_event_listener.cpython-36.pyc │ │ color.cpython-36.pyc │ │ events.cpython-36.pyc │ │ event_firing_webdriver.cpython-36.pyc │ │ expected_conditions.cpython-36.pyc │ │ select.cpython-36.pyc │ │ ui.cpython-36.pyc │ │ wait.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ ├─webkitgtk │ │ │ options.py │ │ │ service.py │ │ │ webdriver.py │ │ │ __init__.py │ │ │ │ │ └─__pycache__ │ │ options.cpython-36.pyc │ │ service.cpython-36.pyc │ │ webdriver.cpython-36.pyc │ │ __init__.cpython-36.pyc │ │ │ └─__pycache__ │ __init__.cpython-36.pyc │ └─__pycache__ __init__.cpython-36.pyc
2.捕获异常可调用exceptions.py使用其中的相应方法
# 需要导入模块exceptions.py from selenium.common import exceptions # exceptions.py代码如下 class WebDriverException(Exception): """ Base webdriver exception. """ def __init__(self, msg=None, screen=None, stacktrace=None): self.msg = msg self.screen = screen self.stacktrace = stacktrace def __str__(self): exception_msg = "Message: %s " % self.msg if self.screen is not None: exception_msg += "Screenshot: available via screen " if self.stacktrace is not None: stacktrace = " ".join(self.stacktrace) exception_msg += "Stacktrace: %s" % stacktrace return exception_msg class ErrorInResponseException(WebDriverException): """ Thrown when an error has occurred on the server side. This may happen when communicating with the firefox extension or the remote driver server. """ def __init__(self, response, msg): WebDriverException.__init__(self, msg) self.response = response class InvalidSwitchToTargetException(WebDriverException): """ Thrown when frame or window target to be switched doesn't exist. """ pass class NoSuchFrameException(InvalidSwitchToTargetException): """ Thrown when frame target to be switched doesn't exist. """ pass class NoSuchWindowException(InvalidSwitchToTargetException): """ Thrown when window target to be switched doesn't exist. To find the current set of active window handles, you can get a list of the active window handles in the following way:: print driver.window_handles """ pass class NoSuchElementException(WebDriverException): """ Thrown when element could not be found. If you encounter this exception, you may want to check the following: * Check your selector used in your find_by... * Element may not yet be on the screen at the time of the find operation, (webpage is still loading) see selenium.webdriver.support.wait.WebDriverWait() for how to write a wait wrapper to wait for an element to appear. """ pass class NoSuchAttributeException(WebDriverException): """ Thrown when the attribute of element could not be found. You may want to check if the attribute exists in the particular browser you are testing against. Some browsers may have different property names for the same property. (IE8's .innerText vs. Firefox .textContent) """ pass class StaleElementReferenceException(WebDriverException): """ Thrown when a reference to an element is now "stale". Stale means the element no longer appears on the DOM of the page. Possible causes of StaleElementReferenceException include, but not limited to: * You are no longer on the same page, or the page may have refreshed since the element was located. * The element may have been removed and re-added to the screen, since it was located. Such as an element being relocated. This can happen typically with a javascript framework when values are updated and the node is rebuilt. * Element may have been inside an iframe or another context which was refreshed. """ pass class InvalidElementStateException(WebDriverException): """ Thrown when a command could not be completed because the element is in an invalid state. This can be caused by attempting to clear an element that isn't both editable and resettable. """ pass class UnexpectedAlertPresentException(WebDriverException): """ Thrown when an unexpected alert is appeared. Usually raised when when an expected modal is blocking webdriver form executing any more commands. """ def __init__(self, msg=None, screen=None, stacktrace=None, alert_text=None): super(UnexpectedAlertPresentException, self).__init__(msg, screen, stacktrace) self.alert_text = alert_text def __str__(self): return "Alert Text: %s %s" % (self.alert_text, super(UnexpectedAlertPresentException, self).__str__()) class NoAlertPresentException(WebDriverException): """ Thrown when switching to no presented alert. This can be caused by calling an operation on the Alert() class when an alert is not yet on the screen. """ pass class ElementNotVisibleException(InvalidElementStateException): """ Thrown when an element is present on the DOM, but it is not visible, and so is not able to be interacted with. Most commonly encountered when trying to click or read text of an element that is hidden from view. """ pass class ElementNotInteractableException(InvalidElementStateException): """ Thrown when an element is present in the DOM but interactions with that element will hit another element do to paint order """ pass class ElementNotSelectableException(InvalidElementStateException): """ Thrown when trying to select an unselectable element. For example, selecting a 'script' element. """ pass class InvalidCookieDomainException(WebDriverException): """ Thrown when attempting to add a cookie under a different domain than the current URL. """ pass class UnableToSetCookieException(WebDriverException): """ Thrown when a driver fails to set a cookie. """ pass class RemoteDriverServerException(WebDriverException): """ """ pass class TimeoutException(WebDriverException): """ Thrown when a command does not complete in enough time. """ pass class MoveTargetOutOfBoundsException(WebDriverException): """ Thrown when the target provided to the `ActionsChains` move() method is invalid, i.e. out of document. """ pass class UnexpectedTagNameException(WebDriverException): """ Thrown when a support class did not get an expected web element. """ pass class InvalidSelectorException(NoSuchElementException): """ Thrown when the selector which is used to find an element does not return a WebElement. Currently this only happens when the selector is an xpath expression and it is either syntactically invalid (i.e. it is not a xpath expression) or the expression does not select WebElements (e.g. "count(//input)"). """ pass class ImeNotAvailableException(WebDriverException): """ Thrown when IME support is not available. This exception is thrown for every IME-related method call if IME support is not available on the machine. """ pass class ImeActivationFailedException(WebDriverException): """ Thrown when activating an IME engine has failed. """ pass class InvalidArgumentException(WebDriverException): """ The arguments passed to a command are either invalid or malformed. """ pass class JavascriptException(WebDriverException): """ An error occurred while executing JavaScript supplied by the user. """ pass class NoSuchCookieException(WebDriverException): """ No cookie matching the given path name was found amongst the associated cookies of the current browsing context's active document. """ pass class ScreenshotException(WebDriverException): """ A screen capture was made impossible. """ pass class ElementClickInterceptedException(WebDriverException): """ The Element Click command could not be completed because the element receiving the events is obscuring the element that was requested clicked. """ pass class InsecureCertificateException(WebDriverException): """ Navigation caused the user agent to hit a certificate warning, which is usually the result of an expired or invalid TLS certificate. """ pass class InvalidCoordinatesException(WebDriverException): """ The coordinates provided to an interactions operation are invalid. """ pass class InvalidSessionIdException(WebDriverException): """ Occurs if the given session id is not in the list of active sessions, meaning the session either does not exist or that it's not active. """ pass class SessionNotCreatedException(WebDriverException): """ A new session could not be created. """ pass class UnknownMethodException(WebDriverException): """ The requested command matched a known URL but did not match an method for that URL. """ pass
3.操作浏览器常会用到如下模块
4.原理
1.selenium client(python等语言编写的自动化测试脚本)初始化一个service服务，通过Webdriver启动浏览器驱动程序chromedriver.exe
2.通过RemoteWebDriver向浏览器驱动程序发送HTTP请求，浏览器驱动程序解析请求，打开浏览器，并获得sessionid，如果再次对浏览器操作需携带此id
3.打开浏览器，绑定特定的端口，把启动后的浏览器作为webdriver的remote server
3.打开浏览器后，所有的selenium的操作(访问地址，查找元素等)均通过RemoteConnection链接到remote server，然后使用execute方法调用_request方法通过urlib3向remote server发送请求
4.浏览器通过请求的内容执行对应动作
5.浏览器再把执行的动作结果通过浏览器驱动程序返回给测试脚本