Selenium應該是目前前端測試最主流的測試工具吧，支援主流瀏覽器如Firefox、Chrome、IE等，無論你熟悉Python還是Java，都可以方便的使用Selenium提供的豐富的測試套件，還有其它很多基於Selenium二次封裝開發的測試框架如Robot Framework可供選擇。

這次是第一次使用Java操作WebDriver，以TestNG作為測試框架，實現簡單的Web前端測試。

IDE: Eclipse Oxygen.3a Release (4.7.3a)
Step1：開啟Eclipse，在Help - Install New Software…中搜索並安裝TestNG外掛

安裝重啟之後可在Window - Show View - Other裡，Java下檢視到TestNG

Step2：使用Eclipse自帶的Maven外掛（或者在Window - Preferences - Maven - Installations新增系統安裝的其它版本Maven），新建一個Maven專案

輸入groupId和artifactId

Step3：在testExample/pom.xml中新增TestNG、Selenium作為dependencies，若只想使用特定的WebDriver實現，如Firefox，可直接新增selenium-firefox-driver作為dependency。

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>testExamples</groupId>
  <artifactId>
 
testExamples</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <dependencies>
    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-firefox-driver</artifactId>
        <version>3.13.0</version>
    </dependency>
    <dependency>
        <groupId>org.testng</groupId>
        <artifactId>testng</artifactId>
        <version>6.14.3</version>
    </dependency>
  </dependencies>
</project>

Alt+F5選擇專案進行更新，可以在Maven Dependencies裡檢查依賴包是否存在

右鍵點選JRE System Library, 改成系統預設

Step4：下載瀏覽器對應的driver放到特定目錄下(如C:\webdriver)，可檢視官網下載地址 。如使用Firefox，需要到這裡下載最新的geckdriver.exe。
Step5：右鍵點選專案，建立一個新的TestNG class並指定package。
可選：
- Annotations，後面可在定義測試類的時候新增
- XML suite file，在這裡新增可直接在package裡生成suite檔案；也可以預設，建立好測試類之後右鍵選擇專案TestNG - Convert to TestNG，會在專案下生成suite檔案包含專案裡不同package的所有測試類。本文暫時不涉及Test Suite的使用。

Step6：實現測試類
用例1：
AUT - http://live.guru99.com/index.php/

測試類如下

package selenium;

import org.testng.annotations.Test;
import static org.testng.Assert.assertTrue;
import java.util.List;
import org.openqa.selenium.support.ui.Select;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.testng.annotations.AfterClass;
import org.testng.annotations.BeforeClass;

public class testPractice1 {
  private String aut_url = "http://live.guru99.com/index.php/";
  private WebDriver driver;

  @Test
  public void checkMainTitle() {
      driver.get(aut_url);
      String title1 = getTitle();
      assertTrue(title1.contains("THIS IS DEMO SITE"));
  }

  @Test
  public void checkMobileTitle() {
      driver.findElement(By.linkText("MOBILE")).click();
      String title2 = getTitle();
      assertTrue(title2.equals("MOBILE"));
  }

  @Test
  public void checkSortByName() {   
      List<WebElement> list1 = getProductList();
      list1.sort((e1, e2) -> e1.getAttribute("title").compareTo(e2.getAttribute("title")));       
      Select sort_type = new Select(driver.findElement(By.xpath("//select")));
      sort_type.selectByVisibleText("Name");
      List<WebElement> list2 = getProductList();
      for (WebElement a:list2) {
          int index = list2.indexOf(a);
          assertTrue(a.getAttribute("title").equals(list1.get(index).getAttribute("title")));
      }
  }

  @BeforeClass
  public void setUp() {
      System.setProperty("webdriver.gecko.driver", "C:\\webdriver\\geckodriver.exe");
      driver = new FirefoxDriver();
  }

  @AfterClass
  public void afterTest() {
      driver.quit();
  }

  public List<WebElement> getProductList() {
      List<WebElement> list = driver.findElements(By.xpath("//h2[@class='item last']/a"));
      return list;  
  }

  public String getTitle() {
      WebElement title = driver.findElement(By.className("page-title"));
      String t = null;
      if (title.isDisplayed()) {
          t = title.getText();
          System.out.println("Current title is:"+t);
      }
      return t; 
  }
}

用例2：
AUT - https://tokenpad.io (借用朋友公司開發的產品頁面)
1. 註冊新使用者
- 測試註冊成功，頁面提示下一步
- 測試註冊失敗，頁面提示警告資訊
2. 登陸
- 測試登陸成功，頁面跳轉到登陸之後的Dashboard
- 測試 登陸失敗，頁面提示警告資訊
在多用例的測試類中除錯單個用例的時候可以用類似@Test(enabled=false)，@AfterTest(enabled=false)來阻止其它用例或步驟執行。

package testPractice;

import static org.testng.Assert.assertTrue;
import static org.testng.Assert.fail;

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.support.ui.WebDriverWait;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.testng.annotations.AfterTest;
import org.testng.annotations.BeforeTest;
import org.testng.annotations.Test;
import java.util.List;

public class Practice2 {
  private String base_url = "https://tokenpad.io";
  private String login_url = base_url+"/auth/login";
  private String signup_url = base_url+"/auth/sign-up";
  private String dashboard_url = "https://tokenpad.io/invest/dashboard/onboard";
  private WebDriver driver;
  private String userId1 = "[email protected]";
  private String passwd1 = "1234qwer";
  private String userbase = "test";
  private String passwd = "12345678";
  private int delay = 3;
  WebDriverWait waitVar = null;

  @Test
  public void checkLoginSuccessfully() throws InterruptedException {
      String expected_text = "Welcome to Tokenpad";
      login(userId1, passwd1);
      Thread.sleep(5000);
      if (driver.findElement(By.tagName("app-init")).isEnabled()) {
      assertTrue(driver.getCurrentUrl().contains(dashboard_url));
      assertTrue(driver.findElement(By.xpath("//div[@class='title']")).getText().contains(expected_text));
      }
      else {
          fail();
      }
  }

  @Test
  public void checkLoginFailed() {
      String expected_alert = "The email or password you have entered is invalid.";
      login(userId1, passwd);
      waitVar.until(ExpectedConditions.visibilityOfElementLocated(By.tagName("alert")));
      assertTrue(driver.findElement(By.xpath("//div[@role='alert']")).getText().contains(expected_alert));
  }

  @Test
  public void checkSignUpFailed() {
      String country = "China";
      String expected_alert = "Your email is already been used.";
      signUp(userId1, passwd1, country);
      waitVar.until(ExpectedConditions.visibilityOfElementLocated(By.tagName("alert")));
      assertTrue(driver.findElement(By.xpath("//div[@role='alert']")).getText().contains(expected_alert));
  }

  @Test
  public void checkSignUpSucceed() {
      String country = "Sweden";
      String userId = userbase+String.valueOf(System.currentTimeMillis())+"@test.com";    
      signUp(userId, passwd, country);
      waitVar.until(ExpectedConditions.visibilityOfAllElementsLocatedBy(By.className("send-validation")));
      assertTrue(driver.findElement(By.xpath("//h2[text()='Confirm Your Email']")).isDisplayed());
  }

  public void signUp(String user, String password, String country) {
      driver.get(signup_url);
      waitVar.until(ExpectedConditions.visibilityOfElementLocated(By.className("login-form")));
      driver.findElement(By.name("email")).sendKeys(user);
      driver.findElement(By.name("password")).sendKeys(password);
      driver.findElement(By.className("ng-arrow")).click();
      setCountry(country);    
      driver.findElement(By.xpath("//button[text()='Create Account']")).click();
  }

  public void setCountry(String country) {
      if (driver.findElement(By.tagName("ng-dropdown-panel")).isEnabled()) {
          List<WebElement> countries = driver.findElements(By.xpath("//div[@role='option']//span[@class='ng-option-label ng-star-inserted']"));
          for (WebElement item:countries) {
              if (item.getText().equals(country)) {
                  int index = countries.indexOf(item)+1;
                  String path = "//div[@class='ng-dropdown-panel-items scroll-host']//div["+index+"]";
                  driver.findElement(By.xpath(path)).click();
                  break;
              }
          }
      }
  }

  public void login(String user, String password) {
      driver.get(login_url);
      if (driver.findElement(By.tagName("app-login")).isEnabled()) {
          driver.findElement(By.name("email")).sendKeys(user);
          driver.findElement(By.name("password")).sendKeys(password);
          driver.findElement(By.xpath("//button[text()='Login']")).click();
      }  
  }

  @BeforeTest
  public void setUp() {
      System.setProperty("webdriver.gecko.driver", "C:\\webdriver\\geckodriver.exe");
      driver = new FirefoxDriver();
      System.out.println("Initialize browser");
      //可以採用隱式設定通用的等待時間
      //driver.manage().timeouts().implicitlyWait(delay, TimeUnit.SECONDS);
      //也可以採用顯式根據條件判斷結果設定等待時間
      waitVar = new WebDriverWait(driver, delay);     
  }

  @AfterTest
  public void afterTest() {
      driver.quit();
  }
}

總結兩點使用心得：
1. 使用Selenium最重要的一點是在不同的web框架之中準確定位元素，在使用xpath的時候，可以藉助瀏覽器外掛如Chrome我使用的是ChroPath來方便的獲取到。
2. 在assert之前給頁面充分的載入時間，比如新增等待時間並通過判斷元素是否顯示、存在的方式確定頁面載入完全了。