运行 使用 Spring Boot、Selenium 和 JUnit 进行 Cucumber 测试时出现 NullPointerException

Question

我有一个简单的基于 Selenium-Cucumber 的测试，当我执行它时会抛出 NullPointerException。

我已经初始化了 WebDriver (chrome) 但由于某种原因测试无法选择它。

不确定为什么在 ChromeDriver

上执行 new 后驱动程序仍未初始化

错误

com.intellij.rt.execution.junit.JUnitStarter -ideVersion5 -junit4 com.example.TestRunner
driver: null

java.lang.NullPointerException
    at com.example.GoogleCalcStepDefinition.I_open_google(GoogleCalcStepDefinition.java:38)
    at ✽.I open Google(file:src/test/resources/features/calc.feature:7)

Feature: Check addition in Google calculatorcontent
  In order to verify that Google calculator work correctly
  As a user of Google
  I should be able to get correct addition result

  Scenario: Addition                     # src/test/resources/features/calc.feature:6
    Given I open Google                  # GoogleCalcStepDefinition.I_open_google()
      java.lang.NullPointerException
    at com.example.GoogleCalcStepDefinition.I_open_google(GoogleCalcStepDefinition.java:38)
    at ✽.I open Google(file:src/test/resources/features/calc.feature:7)

    When I enter "2+2" in search textbox # GoogleCalcStepDefinition.I_enter_in_search_textbox(String)
    Then I should get result as "4"      # GoogleCalcStepDefinition.I_should_get_correct_result(String)

Failed scenarios:
src/test/resources/features/calc.feature:6 # Addition

1 Scenarios (1 failed)
3 Steps (1 failed, 2 skipped)
0m1.364s

java.lang.NullPointerException
    at com.example.GoogleCalcStepDefinition.I_open_google(GoogleCalcStepDefinition.java:38)
    at ✽.I open Google(file:src/test/resources/features/calc.feature:7)

GoogleCalcStepDefinition.java

public class GoogleCalcStepDefinition extends CucumberStepDefinitions {

    private static final String CHROME_DRIVER_EXE = "drivers/chromedriver.exe";
    private static final String WEBDRIVER_CHROME_DRIVER = "webdriver.chrome.driver";
    private static WebDriver driver;

    @BeforeClass
    public static void setUp() {
        System.out.println("Into the setUp() method...");
        String filePath = ClassLoader.getSystemClassLoader().getResource(CHROME_DRIVER_EXE).getFile();
        System.setProperty(WEBDRIVER_CHROME_DRIVER, filePath);
        ChromeOptions options = new ChromeOptions();
        options.setExperimentalOption("useAutomationExtension", false);
        driver = new ChromeDriver(options);
    }

    @Given("^I open Google$")
    public void I_open_google() {
        System.out.println("driver: " + driver);
        //Set implicit wait of 10 seconds and launch google
        driver.manage().timeouts().implicitlyWait(5, TimeUnit.SECONDS);
        driver.get("https://www.google.co.in");
    }

    @When("^I enter \"([^\"]*)\" in search textbox$")
    public void I_enter_in_search_textbox(String additionTerms) {
        //Write term in google textbox
        WebElement googleTextBox = driver.findElement(By.id("gbqfq"));
        googleTextBox.sendKeys(additionTerms);

        //Click on searchButton
        WebElement searchButton = driver.findElement(By.id("gbqfb"));
        searchButton.click();
    }

    @Then("^I should get result as \"([^\"]*)\"$")
    public void I_should_get_correct_result(String expectedResult) {
        //Get result from calculator
        WebElement calculatorTextBox = driver.findElement(By.id("cwos"));
        String result = calculatorTextBox.getText();
        //Verify that result of 2+2 is 4
        assertEquals(result, expectedResult);
    }

    @AfterClass
    public static void closeBrowser() {
        if (null != driver) {
            driver.close();
            driver.quit();
        }
    }

}   

CucumberStepDefinitions.java

@RunWith(SpringRunner.class)
@SpringBootTest
public abstract class CucumberStepDefinitions {

}

TestRunner.java

@RunWith(Cucumber.class)
@CucumberOptions(plugin = {"pretty"}, features = {"src/test/resources/features"})
public class TestRunner {

}

src/test/resources/features/calc.feature

Feature: Check addition in Google calculatorcontent
  In order to verify that Google calculator work correctly
  As a user of Google
  I should be able to get correct addition result

  Scenario: Addition
    Given I open Google
    When I enter "2+2" in search textbox
    Then I should get result as "4"

src/test/resources/drivers/chromedriver.exe

pom.xml

   <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>io.cucumber</groupId>
        <artifactId>cucumber-java</artifactId>
        <version>4.2.3</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>io.cucumber</groupId>
        <artifactId>cucumber-junit</artifactId>
        <version>4.2.3</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>io.cucumber</groupId>
        <artifactId>cucumber-spring</artifactId>
        <version>4.2.3</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-java</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.seleniumhq.selenium</groupId>
                <artifactId>selenium-chrome-driver</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-chrome-driver</artifactId>
        <version>2.45.0</version>
        <scope>test</scope>
    </dependency>

Answer 1

问题是您使用了 JUnit 的 @BeforeClass 注释，而 Cucumber runner 不遵守该注释。

相反，您可以使用 cucumber.api.Before -> @Before 或 @After 注释。

如果您使用这些注释之一来注释方法挂钩，您可以使用 Scenario 接口来获取，例如，运行 场景的标签。

您还可以有多个 @Before 和 @After 方法，您可以像这样提供它们的顺序：

@Before(order = 1)
public void init(Scenario scenario) { }