UI自動化測試底層原理

　　底層原理以下：

　　1.在自動化測試過程當中，存在三部分組件：客戶端腳本+驅動+瀏覽器終端。

　　2.驅動文件，以geckodriver.exe爲例，這個可執行的驅動文件啓動後，至關於一個暴露了一系列接口的服務器，監聽某一端口，例如：89890。

　　3.客戶端的操做（訪問頁面，定位元素，輸入數據，點擊按鈕等）都是封裝成了接口請求（eg：/session/xx/yy），而後提交到驅動服務器。

　　4.驅動服務器接收到客戶端的請求後，再跟終端瀏覽器交互。

　　5.終端瀏覽器作出相應操做。

　　　　下圖描述了整個交互過程：

　　

　　以定位元素爲例，定位搜索框，咱們來看底下這行代碼在執行的時候底層到底經歷了些什麼：

WebElement searchInputBox = driver.findElement(By.id("js_keyword"));

 

　　

實際，底層請求時，每一個請求會被封裝爲一個command，而後根據不一樣的commannd封裝獲得不一樣的HttpRequest對象：

根據此命令，獲得接口地址：

拿到此接口地址封裝爲一個HttpRequest請求。

client.execute（httpRequest，true），執行接口調用：

　　至於其餘操做：往輸入框輸入數據，點擊按鈕等，都是對應一個接口地址，經過調用接口，請求驅動來處理，最後驅動同瀏覽器進行交互，瀏覽器按照指示作出對應操做。

　　Selenium有一個類AbstractHttpCommandCodec，此類中維護了衆多自動化操做對應的接口地址：

　　

public AbstractHttpCommandCodec() {
    defineCommand(STATUS, get("/status"));

    defineCommand(GET_ALL_SESSIONS, get("/sessions"));
    defineCommand(NEW_SESSION, post("/session"));
    defineCommand(GET_CAPABILITIES, get("/session/:sessionId"));
    defineCommand(QUIT, delete("/session/:sessionId"));

    defineCommand(GET_SESSION_LOGS, post("/logs"));
    defineCommand(GET_LOG, post("/session/:sessionId/log"));
    defineCommand(GET_AVAILABLE_LOG_TYPES, get("/session/:sessionId/log/types"));

    defineCommand(SWITCH_TO_FRAME, post("/session/:sessionId/frame"));
    defineCommand(SWITCH_TO_PARENT_FRAME, post("/session/:sessionId/frame/parent"));

    defineCommand(CLOSE, delete("/session/:sessionId/window"));
    defineCommand(SWITCH_TO_WINDOW, post("/session/:sessionId/window"));

    defineCommand(FULLSCREEN_CURRENT_WINDOW, post("/session/:sessionId/window/fullscreen"));

    defineCommand(GET_CURRENT_URL, get("/session/:sessionId/url"));
    defineCommand(GET, post("/session/:sessionId/url"));
    defineCommand(GO_BACK, post("/session/:sessionId/back"));
    defineCommand(GO_FORWARD, post("/session/:sessionId/forward"));
    defineCommand(REFRESH, post("/session/:sessionId/refresh"));

    defineCommand(SET_ALERT_CREDENTIALS, post("/session/:sessionId/alert/credentials"));

    defineCommand(UPLOAD_FILE, post("/session/:sessionId/file"));
    defineCommand(SCREENSHOT, get("/session/:sessionId/screenshot"));
    defineCommand(ELEMENT_SCREENSHOT, get("/session/:sessionId/screenshot/:id"));
    defineCommand(GET_TITLE, get("/session/:sessionId/title"));

    defineCommand(FIND_ELEMENT, post("/session/:sessionId/element"));
    defineCommand(FIND_ELEMENTS, post("/session/:sessionId/elements"));
    defineCommand(GET_ELEMENT_PROPERTY, get("/session/:sessionId/element/:id/property/:name"));
    defineCommand(CLICK_ELEMENT, post("/session/:sessionId/element/:id/click"));
    defineCommand(CLEAR_ELEMENT, post("/session/:sessionId/element/:id/clear"));
    defineCommand(
        GET_ELEMENT_VALUE_OF_CSS_PROPERTY,
        get("/session/:sessionId/element/:id/css/:propertyName"));
    defineCommand(FIND_CHILD_ELEMENT, post("/session/:sessionId/element/:id/element"));
    defineCommand(FIND_CHILD_ELEMENTS, post("/session/:sessionId/element/:id/elements"));
    defineCommand(IS_ELEMENT_ENABLED, get("/session/:sessionId/element/:id/enabled"));
    defineCommand(ELEMENT_EQUALS, get("/session/:sessionId/element/:id/equals/:other"));
    defineCommand(GET_ELEMENT_RECT, get("/session/:sessionId/element/:id/rect"));
    defineCommand(GET_ELEMENT_LOCATION, get("/session/:sessionId/element/:id/location"));
    defineCommand(GET_ELEMENT_TAG_NAME, get("/session/:sessionId/element/:id/name"));
    defineCommand(IS_ELEMENT_SELECTED, get("/session/:sessionId/element/:id/selected"));
    defineCommand(GET_ELEMENT_SIZE, get("/session/:sessionId/element/:id/size"));
    defineCommand(GET_ELEMENT_TEXT, get("/session/:sessionId/element/:id/text"));
    defineCommand(SEND_KEYS_TO_ELEMENT, post("/session/:sessionId/element/:id/value"));

    defineCommand(GET_ALL_COOKIES, get("/session/:sessionId/cookie"));
    defineCommand(GET_COOKIE, get("/session/:sessionId/cookie/:name"));
    defineCommand(ADD_COOKIE, post("/session/:sessionId/cookie"));
    defineCommand(DELETE_ALL_COOKIES, delete("/session/:sessionId/cookie"));
    defineCommand(DELETE_COOKIE, delete("/session/:sessionId/cookie/:name"));

    defineCommand(SET_TIMEOUT, post("/session/:sessionId/timeouts"));
    defineCommand(SET_SCRIPT_TIMEOUT, post("/session/:sessionId/timeouts/async_script"));
    defineCommand(IMPLICITLY_WAIT, post("/session/:sessionId/timeouts/implicit_wait"));

    defineCommand(GET_APP_CACHE_STATUS, get("/session/:sessionId/application_cache/status"));
    defineCommand(IS_BROWSER_ONLINE, get("/session/:sessionId/browser_connection"));
    defineCommand(SET_BROWSER_ONLINE, post("/session/:sessionId/browser_connection"));
    defineCommand(GET_LOCATION, get("/session/:sessionId/location"));
    defineCommand(SET_LOCATION, post("/session/:sessionId/location"));

    defineCommand(GET_SCREEN_ORIENTATION, get("/session/:sessionId/orientation"));
    defineCommand(SET_SCREEN_ORIENTATION, post("/session/:sessionId/orientation"));
    defineCommand(GET_SCREEN_ROTATION, get("/session/:sessionId/rotation"));
    defineCommand(SET_SCREEN_ROTATION, post("/session/:sessionId/rotation"));

    defineCommand(IME_GET_AVAILABLE_ENGINES, get("/session/:sessionId/ime/available_engines"));
    defineCommand(IME_GET_ACTIVE_ENGINE, get("/session/:sessionId/ime/active_engine"));
    defineCommand(IME_IS_ACTIVATED, get("/session/:sessionId/ime/activated"));
    defineCommand(IME_DEACTIVATE, post("/session/:sessionId/ime/deactivate"));
    defineCommand(IME_ACTIVATE_ENGINE, post("/session/:sessionId/ime/activate"));

    // Mobile Spec
    defineCommand(GET_NETWORK_CONNECTION, get("/session/:sessionId/network_connection"));
    defineCommand(SET_NETWORK_CONNECTION, post("/session/:sessionId/network_connection"));
    defineCommand(SWITCH_TO_CONTEXT, post("/session/:sessionId/context"));
    defineCommand(GET_CURRENT_CONTEXT_HANDLE, get("/session/:sessionId/context"));
    defineCommand(GET_CONTEXT_HANDLES, get("/session/:sessionId/contexts"));
  }

 

 

 

　　另外，可能會有人好奇，驅動服務器是什麼時候啓動的服務。實際上是在執行下面這行代碼的時候啓動的，你們可執行去debug調試selenium的底層代碼：

　　

//建立火狐驅動對象
WebDriver driver = new FirefoxDriver();

 

　　當上面這行代碼執行完，能夠發現eclipse的控制檯顯示了以下信息：

 

1531911173760    geckodriver    INFO    geckodriver 0.19.0
1531911173772    geckodriver    INFO    Listening on 127.0.0.1:21984

 

　　說明此驅動服務器成功啓動了，而且監聽了本機的21984端口，等待客戶端發起請求，並處理。

轉載於：http://www.javashuo.com/article/p-nzhldtwu-gt.html