黄瓜：您不能扩展定义步骤定义或挂钩的类 [英] Cucumber: You're not allowed to extend classes that define step definitions or hooks

问题描述

我从其他人那里继承了一个大型测试项目，其主要Java类是CommonSteps，CommonBase和CommonScript。它们目前以这种方式相关：

I have inherited from others a big project of testing whose main Java classes are CommonSteps, CommonBase and CommonScript. They are currently related in this way:

CommonSteps扩展CommonBase

CommonSteps extends CommonBase

CommonBase扩展了CommonScript

CommonBase extends CommonScript

当我尝试使用 mvn clean install 运行项目时，问题出在下一个方法：

The problem is with the next method when I try to run the project with mvn clean install:

@After
public void tearDown(Scenario scenario) {
  if (scenario.isFailed()) {
    // Take a screenshot...
    final byte[] screenshot = ((TakesScreenshot) driver).getScreenshotAs(OutputType.BYTES);
    scenario.embed(screenshot, "image/png"); // ... and embed it in the report.
  }
}

我收到错误：

cucumber.runtime.CucumberException：不允许扩展定义步骤定义或挂钩的类：steps.CommonSteps扩展class common.CommonBase。

cucumber.runtime.CucumberException: You're not allowed to extend classes that define step definitions or hooks: steps.CommonSteps extends class common.CommonBase.

我怎样才能开始使用依赖注入删除与继承相关的所有内容？

How could I start working with dependency injection deleting everything related to inheritance?

推荐答案

Cucumber在每个场景之前创建定义stepdef的所有类的新实例。
然后，当需要运行一个步骤时，它会在这些实例的一个上调用stepdef方法。

Cucumber creates a new instance of all classes defining stepdefs before each scenario. It then invokes stepdef methods on one of those instances whenever it needs to run a step.

如果定义了stepdef方法A类中的foo，你有一个B类扩展A你得到一个a和b实例。
foo方法将在两个实例上都可用，而Cucumber将无法决定调用该方法的实例。

If you defined a stepdef method foo in class A and you have a class B extends A you'd get an a and b instance. The foo method would be available on both instances, and Cucumber would not be able to decide what instance to invoke the method on.

这就是为什么我们不要t允许它。

That's why we don't allow it.

解决方案是使用组合而不是继承。您可以通过依赖注入实现组合 - Cucumber支持几种流行的DI框架。

The solution is to use composition instead of inheritance. You can achieve composition with dependency injection - Cucumber supports several popular DI frameworks.

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